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Home My WebLink About177-027PLUGGING & LOCATION CLEARANCE REPORT State of Alaska · ALASKA OIL & GAS CONSERVATION COFiMISSION PTD NO. Lease Memorandum To File: API No. ~- ~gO~ Well N~e ~o~d~. ~ ~g Location J~ ~0~ rZ~,. Spud: ~'/~d/Y w , Abnd Date Completed Note casing size, wt, depth, cmt vol, & procedure. Long C~: ~'~ ~.~/~ ~ ~ 8~ Liner: Perf intervals - tops: Review the well file, and comment on plugging, well head status, and location clearance- provide loc. clear, code. ~lugs: ~,~ ,~i~ /~o ~ ') /~-~ ~ ~. ~-~-~- Well head cut off: Marker post or plate: Location Clearance: Conclusions.: Code Date -/DEP~~T CF ~ ~ ·Divisicn of Oil and ~.~ Conservation May 22, 1978 Fi~_a! Abandonment IXAE's Doyen %3 Wednesday, May 10, 1978 - I departed my ~ at 6:45 ~M for a 7:15 AM showup and 7:35 A~--departuze via I/AE chartered Merlin for LL&E's $3 · Lawnm~e Davis, LImE representati~, for inS~ect3x~ for final ab~m~x~nt of this locatic~.~' We arrived at 10:10 AM and the air crew dr~ me · Pi~ No. 1 ~ shot loddng ~ north %oward the fon~_r reserve pit location. Picture No. 2 ~s of the w~Ll markar with all I~_-~ir~nt data fcxu~r reserve pit area. ':-Pi~._ No. 4 ~s of the foxier locatic~ of rig c~ and eng/nes, and ~ld/ng sb0p. Picture No. 5 is of the f~ camp area. Pictur~ No. 6 is of the access road e~terlng the location. Picture No. 7 was taken looking northeast toward the ~ marker and access road.' Picture No. 8, taken from the a/r, shows the entire locatic~ ~nd aco~ss road. ~he s~.~ace of the location is c~sed of crushed 1/me~ and has been I departed Doyc~ %3 via ~essna 402 at 1:45-AM and arrived at Doyen #1 at 2:15 PM. We departed Doyen %1 at 2:25 PM, refueled in Fairbanks and arrived in Anchorage at 5:00 PM. I arrived at my hare at 5:30 PM. approved final aban~t of LLAE's ~ %3. Drlg. Permit Operator /_.., AI~,.~..~ Oil and Gas Conservation Commi(' '~" Field Inspection RePort /.,~ ~~ Wel 1/t>zl~t=$~ Sec~o T~A~R~L--, F M Represented by.j~V~,~ Name & Number~ Satisfactory Type Inspection Yes No Item ( ) Location,General () () () () () (' ! () () () () () 1. Well Sign ( ) ( ) 15 2. General Housekeeping ( ) ( ) 16 t. Reserve Pit-( )open( )filled ( ) ( ) 17 4. Rig ( ) Safety Valve Tests 5. Surface-No. Wells 6..Subsurface-No. Wells ( ) Well Test Data ) ( ) 7. Well Nos. , , , ) ( ) 8. Hrs. obser , , , ) ( ) 9. ~s~w , .~,--, () () 18 ( ) ( ) 19 () () 20 () () 21 ( ) ( ) 22 ( ) ( ) 23 () () 24 () () 25 Satisfactory Type Inspection Yes No Item ( ) BOPE Tests "Casinq set ~ _ TesL fluid-( )wtr. ( )mud ( ) oil Master Hyd. Control Sys.- psig ~!2 btl s. , , ,__psi9 Remote Controls Drilling spool- "outlets Kill Line-( ) Check valve Choke Flowline ( ) HCR valve Choke Manifold No. valvs flms Chokes-( )Remote( )Po.s.(-~dj Test Plum-( )Wel?hd( )CSQ( )none ) ) 10. Gr. Bbls. , , , ( ) ( ) 26. Annular Preventer,__~osim '(~7',Final Abandonment ( ) ( ) 27. Blind R. ams, psie ~ ) 11. P&A Marker ( ) ( ) 28. Pipe Rams psiq ) ) lZ. Water well-( )capped( )plugged ( ) ( ) 29. Kelly & Kelly-cock psig ~ ( ) 13. Clean-up ( ) ( ) 30. Lower Kelly valve psio ~- ( ) 14. Pad leveled ( ) ( ) 31 Safety Floor valves--L-(- -)-BV { )Dart Total inspection obser'vation timey~_hrs/~N=9~ Total number leaks and/or equip, failures~_<:~ Remarks Inspected by~_ ~a te cc- Notify in days or when ready DEPARTMENT OF NATURAL RESOURCES DIVISION OF OIL ANO GAS Conservation JAY S. HAMMOND, GOVERNOR 3001 PORCUPINE DRIVE-ANCHORAGE 99501 February 1, 1978 Clary Insurance Agency 803 W. Fifth Avenue Anchorage, Alaska 99501 Attn: Sherri Burr Dear ~iiss Burt: This letter is in response to the request of the Louisiana Land and Exploration Company to release their blanket bond for all wells drilled in the State of Alaska. The bond number assigned by your company is I~lA-MO4-5510. Our Oil and Gas Conservation Con~ttee drilling bond executed on Form P-2 was approved December 24, 1975. The penal amount was $100,000.00. The Oil and Gas Conservation Cc~ttee hereby releases the Louisiana Land and Exploration Cc~t~pany frcm the stipulations of their $100,000.00 drilling bond in view of the fact that the Division of Oil and Gas Conservation has approved the abandonment of all wells drilledunder this bond and no wells are currently d~illing. Sincerely, ~os. R. ~.~shall, Jr. ~e~tive Secret~ ~aska Oil ~d Gas Conse~ation Co~tt~ cc: Louisiana Land and. Exploration Ccmpany Suite 202 550 West 8thAvenue Anchorage, Alaska 99501 THE LOUISIANA LAND AND EXPLORATION COMPANY SUITE 202 - 550 WEST 8TH AVENUE PHONE (907) 276-7545 2%_NCHORAGE, ALASKA 99501 November 8, 1977 O. K. Gilbreth State of Alaska Division of Oil and Gas 3001 Porcupine Drive Anchorage, Alaska Re: Final Logs Doyon #3 Well Kandik Basin, Alaska Enclosed you will find an original and sepia of the following final logs for the referenced well. 1. Compensated Formation Density Log-Gamma-Gamma-scale 5"//100' 2. Compensated Formation Density Log-Gamma-Gamma-scale 2"//100' 3. Dual Laterolog-scale 5"/100' 4. Dual Laterolog-scale 2"/100' 5. Dual Induction Laterolog-scale 2"/100' 6. Dual Induction Laterolog-scale 5"/100' 7. Borehole Compensated Sonic Log-scale 2"/100' 8. Borehole Compensated Sonic Log-scale 5"/100' 9. Compensated Neutron Formation Density-scale 5"/100' We wish to keep this information confidential for the statutory time period. Please acknowledge receipt of said logs by signing and returning a copy of this letter to me. Yours very truly, THE LOUISIANA LAND AND EXPLORATION COMPANY Lawrence Davis Project Manager LD: lh Enclosures Received this ay of~~? ¢~ ~ _ THE LOUISIANA LAND AND EXPLORATION COMPANY SUITE 202 - 550 WEST 8TH AVENUE PHONE (907) 276-7545 _ANCHORAGE, ALASKA 99501 September 16, 1977 State of Alaska Division of Oil and Gas 3001 Porcupine Drive Anchorage, Alaska Received from The Louisiana Land and Exploration Company: One -(1) complete set of dry samples from Doyon #3 well. Received by: On this /~.3 Form P--7 S SUBMIT IN Di /;* .fATE OF ALASKA ',~,-,-o:;:~,'ln- st ructions on OIL AND GAS CONSERV?TION COMMITTEE ~ever~e Mde, WELL COMPLETION OR RECOMPLETION REPORT A~D LOG* , la. TYPE OF WELL: 0IL ~ ~aS WELL WELL ~ DR~ ~ Other b. TYP~ OF ~O~PL~ON: WELL OV~R EN BACK nEsva. Other 2. NAME OF OPERATOR The Louisiana Land and Exploration Company 3. ADDRESS OF OPERATOR 550 West 8th Avenue, Suite 202, Anchoraqet Alaska 9.9501 2. LOCATION OF WELL (Report location clearly and in accordance with any State requirements)* At surface 2696 ' south and 1360 ' east of NW car. At top prod. interval reported below Sec. 20 T23N R28E F.M. :L At total depth 13. DATE SPUDDED 5-30-77 18' TOTAL DEI='TH, 1VLD & TVD [Lg. PLUG,B'A,cK MD & T~VDr- IF 1VI-ULT~ CO~L., [21. I-][O%V At]-A~IY* ROTARY TOOLS x 13,533 P & A surface 2~. PRODUCING I1N'r~VAL(S), OF 'l'bllS COMPL2gTIO~XI--TO/~, BO/~EOM, NA~IViE (MD AND /W/))' !' i'~' 5. AP1 NUMERICAL (~)_Dl!l ....... 50_ 043_ 204:0-~-" '~' 6. ME DmIGNA~N ~D Doyen, Lfi~. '~ 8. UNIT,F~ OR L~SE 'NAME Doyen, Ltd g. WELL NO. #3 10. FIELD AND POOL W±ldcat 11. SEC., T., R., M.. (B OBJECTIVE) Sec. 12. PERMIq_' NO. ELEVATIONS (DF, RKB, RT, GR, gTC)* 17. EL,EV. CASINGHEAD ' 1794 ' 9-10-77 9-13-77 KB-1821 ' . ~ INTERVALS DRILLED BY 24. TYPE ELE-CTI%IC AND OTI-IE~ LOGS RUN to T.D. [ cA.,.~. TOOLS 23. WAS DIRECqqONAL I SURVEY MADE NO t DIL - CNL Den.sity- BHC Sonic ,, 25. CASENG RECORD (Report all strings set in w£11) CASLNG SIZE I WEIGHT, LB/FT.~ GRJkDE i DEPqWrI SE,T. (,1¥/))t HOLE SIZE] 30" / 300# !H-40 I ~1' I 36" 20" [ 94# /~-SSB~ 194' I 26"[ 13 3/8" / 72# ]N-S0BT~ 2296.3' 117 1/2" , 9 5/8" p35# & 47# /N-80Bm~ 8497.48'112 114" go. LINER lq.E C Olq.D 28. PERFORATIONS OPF./N TO PRODUCTION (interval, size and number) 30. PR, OD UCTION CEkMLN TING REC OtLD iA. MOUNT PULLED _ 0 _ - 0 - 0 ' 0 475 sx. permafrost 595 sx. permafrost 1318 calseal & Class G 750 sx. Class G 27. TUBING RECO}~D 29. ACID, SHOT, Fi~AC'i'URE, C?-,\IENT SQUE~E, ETC. D .~Tii INTIiiRVAL (MD) ] AMOUNt ;.~ND KIND O.F MATERIAL USED 1 , . . DATE FIRST PI%eDUCTION [ FRODUCT1ON ME2h[OD (Flowh~g, .g:is lif~, pumping--size and type of pump) DATE OF T~ST, [ _ [P~OD'N FOR OI~BBL. Gzk~R'ICF. ~O'W, TUBING CASING PKESSU~ [CALC~D OI~BBL. 31. D~sPoS~T~ONOF ~*S (Sold, u~ed /$r tuel, vented, etc.) 32. LIST OF ATTACHMENTS [ViELL S'FATUS (Producing or [ ~A'A TEl%---13 EL. [GAS~OIl, I%ATIO ]WA~BBL. lOlL GRAVITY-~I (CO~.) TEST WITNESSED BY 23. I hereby certify that the foregoing an/il attached information is complete and correct as determined from all-available records SIGNED ~ -- TITLE Project Manaqer *(See Instructions and Spaces for Additional Data on Reverse Side) INSTRUCTIONS General: This form is designed for submitting a complete and correct well completion report end log on all types of lanJs and leases in Alaska. · ltemi'16:' Indicate which elevation is used as reference (where not otherwise shown) for depth measure- ments .given in other spaces on this form and in any attachments. : Items '~0, and :2:2:: If this well is completed for separate production :from more than one interval zone (multiple completion), so state in item 20, and 'in' item 22 show the prcducing interval, or intervals, top(s), bottom(s) and name (s) (if any) for 0nly.the interval reported in item 30. Submit a separate report (page).on this form, adequately identified, for each additional interval to be seperately produced, show- ing the additional data pertinent to such interv,.al., Item:26: "Sacks Cement"..: Attached supplemental records for this well should show the details of any mul- tiple,.s,ta, ge cementing and'the location of the cementing tool. Item :28: Submit a separate completion report on this form for each interval to be separately produced. · (See,,.i,n.,s. tructio.n for items 20 and 22 above). .~;: ~.~4. SUMMARY OF FORMATION TF~TS INCLUDIN(i INTEP~VAL TESTED. P~URE DATA ~ ~OV~ OF 01~', ~ , ~ . , ,, ,. . ~ (; ~ . · [.... . . . .~ ~'u: ~ ~ : ..~ ' ]"~ , aS; COR~ DATA. A~Clt BRI~ b~CRIPI~O~S OF LITHd~bG~,~ POROSITY. FRAc~R~.: APp~NT DIPS L r ,, '' i_ , ,,. , . ' ",,E :. " '~' . ' ''" . · ' ..: : ' -.' , , , , .f-~ :. ,.-: . .. , '7 ~ ~' , · . . : ~ · , ~ - ,.,.. ,,, WELL DATA SHEET I.N.C. Bl. ackfl.2. YT M-55 - 44 miles from Doyon #2 Abandoned April l, 1970 T.D.' 6790' 13-3/8" @ 245' 9-5/8" @ 1690' Mud System Treated Gel 0-255' Aerated lime water 255' to' 1245' Gel slurry 12~3' to 1690' Aerated water 1690' to 6790' Maximum MUd Weight 8.8# per gallon Maximum Deviation 19o at 6494' Cut 5 Cores Hole Size' 17-1/2" HO' 0-255' 12-t/4" 255' to 1690' 8-3./4" 1690' to 6790' T.D. 6790' · From spud to T.D incl. P&A - 78 days Average ROP = 87' per day Average ROP in 8-3/4" hole = liS' per day Rotating hours = 916 = 7.41' per hour = 177.84' per 2~ hour day -2- WELL DATA SHEET Inxco Porcupine G-31 51 miles from Doyon #2 Abandoned March 24, 1972 T.D.' 3720' 13-3/8" at 988' 9-5/8" at 4900' Mud System Gel caustic O' to 988' Air 988' to. 1420' Air foam 1420' to 6080' Water 6080' to 8697' Gel caustic 8697' to 8720' Maximum Mud Weiqht 9.2# per gallon Maximum Deviation 9-1/2° at 3175' Cut 2 Cores Hole Size' 12-1/4" open to 17-1/2'l O' to 988' t2-1/4" 988' to 4900' 8-3/4" 4900' to 8720' T.D. 8720' From 'spud to T.D. incl. P&A - 85 days Average ROP = 102.58' per day Average ROP in 12-1/4" hole = 86.93'/day (Total) = 195.6'/day (Less trouble) Average ROP-in 8-3/4" hole = 191.O'/day (Total) Rotating hours = 600 = 14.53' per hour = 348.72' per 24 hour day · -3- WELL DATA SHEET Western Minerals N. Hope YT N-53 100 miles from Doyon #2 Abandoned August 13, 1970 T.D.' 14,045' 20" Conductor at ? 13-3/8" at 1522' Mud SSs tem Gel - Benex O' to'8300' Gel - DV-68 8300' to 9700' Extended Gel 9700' to 14,045' Maximum Mud wt. 9.7#/gal. Maximum Deviation 250 at 13',820' Cut 1 Core Hole Size' 8-3/4" opened to 12-1/4" opened to 17-1/2'~ O' to 1500' 8-3/4" 1500' to 14,045' T.D. 14,045' From spud to T.D. incl.'P&A - 117 days Average ROP = 120.04' per day Average ROP in 8-3/4" hole = 137.85' per day Rotating hours = 1564 = 8.98'per hour : 215.52' per 24 hours -4- Drilling Services (International) Ltd. Manager: CHAMAN MALHOTRA 1400 ELVEDEN HOUSE, CALGARY, ALBERTA, T2P 0Z3, Telephone: (403) 264-3145 HUSKY BLACK FLY M-55 2 WEN - 1 RLD January 15, 1970 Circ. lost at 180' with mud (12 1/4 hole) January 16- 17 Drill to 260' wi th air Set 13 3/8 to 255' (17 1/2 hole) 'January 20 Try to dry hole - hole making water January 21 - January 27 (500 CFM - 400 PSI) Drill with aerated water 300' to 1243' = 943' January 28- February 4 Fish for collars Mud up to fish and drill ahead wi th mud Set 9 5/8 to 1690' February 4 Drill out with mud (8 3/4 hOle) Lost circ. at 1775' Drill wi th aerated water 800 CFM 300 PSI - 380 GPM February 4- March 19 (800 CFM - 400-500 PSI) 380 GPM Drill wi th aerated water (' 8 3/4" hole) 1775' to 6790' = 5015' (20M to 35M on bit) Hole sloughing- change to mud Core at' 3158' 3787' 4076' 4927' 5370" Y Air Drilling .Services (International) Ltd. ~~400 ELVEDEN HOUSE, CALGARY, ALBERTA, T2P 0Z3, Telephone: (403) 264-3145 Manager: CHAMAN MALHOI'RA INEXCO ET AL MALLARD 2 WEN - ESI - RLD Set 13 3/8 to 356' with mud May 12 to 15 (incl) (1400 CFM - 150 to 350 pSi) 956' to 1855' = 899' Mist Drilling WEN Down - cannot clean hole - change to mud - SP1200 - RLE (9 1/4) - M.P. - Doghouse - Blouey Line & Gates - 9" Hammer - 12" Rot. Head - 20" Rot. Head - 20 Bbls. Soap - 15 Sacks Inhibitor Total Weight - Approx. lO0,O00 lbs. TRUCKING · - 3 loads to Fairbanks 4000.O0/Load (includes loading) (does not include unloading) 2½loads Hercules Loads. Drilling SerVices (International) Ltd. Manager: CHAMAN MALHOi'RA 1400 ELVEDEN HOUSE, CALGARY, ALBERTA, T2P 0Z3, Telephone: (403) 264-3145 9" Hammer Cost : $3100. O0/mon th min. - $20.O0/Hr. running time WT. : 875# · Grant Heads 23 1/2 Table will pass 14" Bit (12" or 13 5/8" head) 27 1/2 Table will pass 20" Bit (20" head) 20" cost = '$84 O0/day (10 day min.) ($84.00 includes spool) $25.00/day Stand-by~ 12" cost = $58.00/day (10 day min.) $25. O0/day Stand~by ,Rubbers = $325.00 each 20" WT. = 4200# 13 5/8" WT. = 3500# 12" WT. = 2700# Air Drilling Services (International) Ltd. Manager: CHAMAN MALHOI'RA 1400 ELVEDEN HOUSE, CALGARY, ALBERTA, T2P 0Z3, 'Telephone: (403) 264-3145 INEXCO HUSKY AMOCO G-31 PORCUPINE 3 WEN-- ESI - RLD Set 13 3/8 to 988' wi th mud .January 10, 1972 Can not dry hole - drill with M.i~t (12 1/4 hole) Janaury 11 to January 16 (incl) (1400 CFM - 200 PSI) Mist Drill with Hammerdril (12 1/4 hole) 988' to 2341' = 1353' January 17 to February 5 Fishing for bit and whipstock February 6 to February.Il (incl) (1700 CFM - 200 PSI) Mi st Drill wi th Hammerdril 2600' to 3716' = 1116' February 12 to February 16 (incl) Wait on fuel February 17 to February 24 (incl) (2100 CFM z 200 PSI) 3716' to 4900' = 1184' February 25 to February 29 (incl) Ran 9 5/8 Csg. to 4900' March 1 - March 6 (incl) (2100 CFM - 180 to 800 PSI) 4900' to 6085' = 1185' Hole making too much water - change to mud ELF 0IL: Elf Ex Et al Wllkie point .... J-51 Ma~ch 17/75. to March 2 I/75. Ma~ch 24/75. to March 26/75. .Making too much 'water. Waiting on casing. March 31/75. to Apr~ 4/75. 0' to 535' 535' to 1466' 2025' to 3521' 17~" hole. 12~" 'hole. 8~" hole. PANARCTIC OILS: W~st Pollux E-59 - E~lef Ringn~s Isl.~ N.W.T. Oct. 13/73. to Oct. 15/7~ 70' to 1583' 12~" hole. Sir~-us K-28 - Ellef 'Ringnes IS ~N.W.T. Nov. 26/73. to Nov. 28/73. 86' to 968' 174" hole. Arco et al Blue Fiord E~46 -~Bjorne Peninsula. Oct. 8/74. to~ Oct. 11/74. Oct. 16/74. to Oct. 26/74. 0' to 626' 890' to 3286' 174" hole. 12P~" hole. REA POINT K-32 May 14/74. to May 15/74. Set surf ac e casing May 17/74. to May 20/74. (AIR) (AIR)~ 0' to 415' 426' to 2000' 7 5/8" hole 4 3/4" hole Hom~tead Porcupine N. Sabine 'H-49 May 3/74. to May 7/74. 0' to 1075' 174" hole. PANARCTI C 01LS: Gulf W. C.~ ~et~al Ne~~ 0 ~15~ N~l'Peni~ula, N.W.T. March 18/74. to March 23/74. M~rch 24/74. - Drilled 60' with mud. March 25/74. to M~ch 26/74. ~Changed to mud. April 5/74. to Ap~l 7/74. Changed to mud.' 120' to 835' 985' to 1529' 3178' to 4168' 17~" hole. 12~" hole. 8 3/4" hole. KMG Deca~ta' F-6~ Young 'Bay, N W.T. May 2 7/75. to May 30 / 75..~. ~'~ ~n May 31/75. to June 1/75. Run 9 5/8" surface casing. June 3/75.~to June 6/75. ~ Mudded up at 1987' on June 6/75. 0' to 556' 556' to 715' 715' to 1987' 12~" hole. 12~" hole. 8 3/4" hole. Castel Bay C'68 - Jan. 29/75. to Feb. 1/75. Waiting on surface pipe. Feb. 9/75. to Feb. 12/75. 41' to 1020' 1150' to 1748' 17~" hole. 12~" hole. CHEVRON STANDARD LIMITED:~ Shaeffer Creek 0-22 = 'Yukon Jan. 12/70. to Jan. 13/70. Gas at 698'~- mudded up. Jan. 28/70. to Jan. 31/70. Mudded up. 73' to 698' 1207' to 1852' 17~" hole. 8 3/4" hole. S.O.B.C. Wm. East Porc. 1-13- N.W.T. Feb. 10/71. to Feb. 12/71. 70' to 455' 17~" hole. Chevron S.O.B.C.~ W ~Par~n 'C'33 ~ ~Eagle Plains, Yukon. Nov~ 29/71. to Dec. 2/71. 0' to 824'- 17~" hole. Chevron North Parkin ~ ~D-61 - Yukon. Jan. 5/72. to Jan. 8/72. 100' to 730' 17~" hole. Chevron Birch E-53 Jan. 20/72. to Jan. 22/72. Jan. 29/72. to Feb. 5/72. 0' to 737' 758' to 1620' 12~" hole. 8 3/4" hole. Change to mud. Chevron South Chance D-63 Feb. 21/72. to Feb. 27/72. Surface hole completed at 1020'. Chevron Porcupine F~ 18 ~Yukon 'March 6/72. to March 9/72. · Change to mud. 66' to 1020' 0' to 806' 17~" hole. 12~" hole. Chevron S.O.B.C. Gulf ~idge F-48 Jan. 3/73. £o Jan. 9/73. Jan. 9/73. to Jan. 10/73. Jan. 11~73' to Jan. 12/73. 54' to 673' 673' to 793' 793' to 886' 17~" hole. 12p~" pilot 17~" hole. Chevron S.O.B.C. Whitefish J-70 Yukon Jan. 17/73. to Jan. 18/73. Jan. 18/73. 0' to 216' Changed to mud. 17~" hole. Chevron Wm. E. Pine Creek~Yukon Dec. 25/71. to Dec. 26/71. Dec. 27/71. 77' to 314' 314' to 822' 17~" hole. 12~" hole. Taylor Consulting 4705 Piper Street Anchorage, Alaska 99507 907 274-£474 Service THE WATER-WELL DRILLING PROJECT AT DOYON ~ WELL,,SI~,E, Submitted to: Mr. Lawrence Davis Project Manager The Lo'uisiana Land and Exploration ~0 West 8th. Avenue Suite 202 Anchorage, Alaska 99~01 By: Georg~ W. Taylor consultant Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 ABSTRACT Nine (9) bore holes were drilled in the vicinity of LL&E's well site designated Doyon #3 for the pur- pose of providing water for camp and oil well drilling rig use. No useable water was produced from any well. The six-inch diameter wells ranged in depth from only 100 feet, to a depth of 69~ feet. Severe lost-circulat- ion problems were encountered in all wells drilled at or near the location for the proposed oil well Doyon #3. The depth of the permafrost/permanently frozen zone was not fully established. It appeared that the 400/440 feet deep lost-Circulation zones might be related to the base of the permafrost, but this was not established beyond reasonable doubt. The general lithology drilled proved to be'massive limestone. This rock was medium to dark gray in color, massive, jointed and fractured. A stratum of decomposed carbonate was drilled in two wells~ with the contact found to be at a depth offS60' in WW-2, and at a depth'of 300' in WW-~. (The surface elevation of these wells is 1,680', and 1,500'.) The failure of the described drilling appears to have left LL&E with no other option than to pump water through a surface pipeline some six or eight miles to the well site during the warmer months, and to resort to hauling from this same 8-acre lake over an ice road during cold weather operations. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 ABSTRACT ( cent ' d. ) A phenomenon was Observed whereby all holes that were drilled to depths where circulation was lost' freely took in air, or expelled'air into the atmoaphere, depending upon barometric pressure. At: the greatest measured air velocity, ~-1 was estimated to be blowing air through the 6" diameter surface casing at a daily rate equal to 1,800,000 cubic feet (1 .8 MMD). When first obserVed, the subsurface "reservoir" or "void" was calculated to be underpressured to only 11 .9 psi, or 27.~0 inches/mercury. A aircraft-type altimeter was used to record data over a period of several days,. and this "reservoir pressure" (absence of pressure) was found to vary widely, both up and down the scale of barometric pressures. It is believed that open joints and'fissures in the limestone, that are not filled with fluid because of the permafrost, lead to larger sol'ution cavities at depth. When the atmospheric pressure is high, air moves freely through the open well bores and is stored in quite infinitely large voids (cumulative void space) in the subsurface. Subsequently, when the atmospheric pressure dro'ps significantly, this air moves from storage and is expelled back into the atmosphere which is now at a lower press'ufo than 'the air stored w:i. tt~.in the sub- surface "voids". Taylor Co'nsul ing S.erv ce 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 ABSTRACT (cont ' d. ) Several other "theories" regarding the described phenomenon have been considered and rejected in favor of the one presented'here. Other possibilities might be: Sublimation of permafrost. Faulted zones out- cropping at the surface, with prevailing winds creating an air foil. A source of subterranean heat warming the air induced through the well bores, causing it'to expand and be 'expelled from the heating/expansion chamber. It is not inco~ievable that solUnar influences, ambient temperature, photo variance (changing light intensity), diurnal temperature variance, movement of ground water at depth, and a great number of other factors may well contribute to the conditions described. However, there seems little doubt that giVen extremely stable conditions whereby the atmospheric pressure might remain fixed at or near "standard day" conditions, that air movement in or out of the boreholes would cease at some point of time with the "reservoir" pressured to near "standard day" values. Ail holes.were plugged with crushed rock and permafrost ceraent to the surface. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 EQUIPMENT AND METHODS USED Hatch Drilling of Fairbanks was contracted to drill the water wells. A Chic'ago Pneumatic 650 rotary drilling rig with~sufficient drill stem to reach 440' depths was flown into Grayling Fork ice airstrip and sledded fifty miles overland on the cat-train used to move equipment for the Doyon #3 construction project. This rig has good capability, with some Unusual and worthwhile features. The drill head can apply 65,000 inch-pounds of torque, the rig ' is capable of applying 30,000 pounds w.eight-on-bit. The rig normally uses air as a means of circulating the cuttings from the hole, but has the ability to use drilling mud or fo~n. Drill pipe (drill stem)' sufficient to reach a depth of 845' was later flown to the 'location. The wells were spudded after snow and brush had been removed l~rom a work area. A regular rock bit was used to drill the surface peat and soils. Steel casing of 6" diameter Was set to solid rock, and the drilling resumed with a percussion bit. This is a device that uses a tungsten- carbide insert, flat- faced bit, commonly called a "hammer". The bit is actuated by pneumatic force via air from truck mountod ed from tho quarry to supply adc].i'bional air vo].u~no. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99;507 907 274-2474 The percussion bit generally achieved good rates of penetration, on the order of 1J/2J feet-per-hour in good limestone. The auxiliary air compressor was a necessity when drilling below about 400' depths. Attempts to core the lost-circulation zones generally failed due to having drilled blindly (without circulat- ion) through certain of'these zones prior to obtaining core ~arrel and bit. Cores were taken in certain holes~ however~ the~e failed to be of much practical use as related to the water-well program. The first barrel and diamond bit received was too large to be used in the holes being drilled. A second barrel and tungsten- carbide coring bit was obtained in Anchorage. This proved to be a good piece of equipment. The carbide coring bit cut all but one core taken quickly, with no undue wear to the bit itself. Well cuttings (samples) were sacked at intervals from each well. Most of these were delivered to the mud-loggers and consulting geologist at Doyon ~2 oil well drill site. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 This well was located at the west edge of drill _pad for the oil well that will be designated Doyen #3. The well was spudded February 17. Eight feet of frozen soils and weathered carbonate rock wag drilled with a conventional' tri-cone rock bit. Six-inch (6") steel casing was set on solid limestone at a depth of eight feet and drilling resumed with a percussion-bit. Good rates of penetration of about 15-20 feet per hour were achieved. The formations encountered were all variations of Carbonate rock, with typical gray limestone predominant. Circulation of air was interrupted suddenly at a depth of 390'. Drilling was resamed without circulation to a depth of 405'. While waiting on core equipment in order to evaluate the stratum where circulation was lost, the rig was moved to location and ¥5V-2 was drilled. The rig was later moved back to this location, and the hole deepened to 4~l.0'. This zone drilled rapidly using a tri-cone rock bit as it was feared that the body of the percussion bit device might be more easily stuck in the hole while drilling without circulation. For comparison, the same rock bit that achieved 20 feet per hour in the interval 405' to 440' in this well, was able t° make only 2'0" of hole in 4~ minutes in a. test hole drilled on the east side of the drill pad. This experiment should give some indication as to the relat- ive di'fforences in the rock as tho "typical" dense gray limestone proved much more resistant to the bit than did the unidentified strat~n where circulation was lost. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 ~'~-1 ( cent ' d. ) ~ ,, A core was taken at 1!~!0'-44J' depth with good recovery. The core was composed of gray limestone, broken laterally, with some calcite veining, and slight solution channeling along fractures. It is felt that this core.probably does not represent the previous fifty vertical feet that yielded so easily to the tri-cone rock bit, and so completely consumed tho rather large volumes of air used in attempts to regain circulation. A Gardner-Denver "600" air compressor was employed along with the "l[J0" (CFM) rig compressor in an attempt to re-establish circulat- ion in this well. A high viscosity drilling mud containing two types ofI lost-circulation materials (Magco-Fiber and Cell-0-Seal) was pumped into this well with the bit at 42J' and the 600 (+) seconds-viscosity synthetic polymer (DuoVis) fluid came back up the annulus to 399'...and went into the formation at that point. Two permafrost cement plugs were placed in this hole, separated by ten vertical feet where' the hole was packed off with a plug of Cell-0-Seal and Fiber, for the' purpose of ensuring that the cement would not bo lost to the formation, and would return to the surface. Tt~c well was successfully comon'bod in tl~is inanI'lor. Wl'~e surface elevation o£ WW-~ is ~,gO0~. Tho actual W.D. was 462~. 7 .Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 This well was located one-quarter mile southwest of the Doyon #3 drill site pad. It was spudded Feb. 25, casing set at 25.' and dril!ed to 440', where circulation was lost suddenly and completely. This lost circulation zone was thought at the time to correlate with the 390' zone of lost circulation in WW-1, but was never proven to be related. The surface elevation of the two wells is 1800' and 1680' respectively. An additional Gardner-Denver "750" (CFM) air comp- ressor was employed, and circulation eventually was re-establishe~ after drilling ahead for a considerable time. Apparently, the acc.umulated volume of drilled solids eventually sealed off the passage of air to the formation, and circulation was resumed. A core was taken while drilling a soft, friable, tan/yellow weathered limesone or carbonate residue of the interaction of ground water on carbonate rocks. As it happened, the actual contact of this friable formation with underlying competent gray limestone was cored, with the depth determined to be ~60'. The gradation or zone of~transition was abrupt, only some 3" of weathered limestone separating the loose yellow material from firm gray limestone. This sarae contact was apparently drilled at a depth of ~00' in WW-~:'.~, whic]'~, had a surfaco elevation of 1~00'. WW-2 was drilled to 69~' and abandoned in dry gray limestone, tho drilled cuttings having the appearance of cement. This well was filled with crushed limestone prior to cementing to the surface with permafrost cement. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 Location of WW-3 was the East edge of the drill pad for Doyon #3 oil well. The hole was spudded March 3, casing set at five (5) feet on hard rock, the hole drilled to'442', where circulation was lost abruptly. The rock was somewhat harder than WW-I~ located directly across the drill pad, some ~00' west of WW-3. A core was taken at. point of lost circulation, but yielded only hard, fractured, gray limestone. Tt~e wall was abandoned and later filled to 400' with crushed limestone from the quarry, cemented, packed off with well cuttings at 400', the remainder of the hole filled to the surface with crushed rock, and cemented with permafrost cement to the surface. WW-3 waS actually a "test well" drilled for the purpose of obtaining subsurface geologic data relati~.e to the drilling of Doyon #3 oil well~ Little was learned from this well other than slightly harder rock was drilled than was encoUntered, 500' west in WW-1, and that the zone of "lost circulation" was not a large cavern or void. This well, more than any other drilled, indicated that circulation was lost by drilling one of the numerous vertical "joints" which is typical of massive limestone. Limestone of this nature tends to shrink with th~ passable of' time, creating extonsivo vortical joinbs, in ~ddit:i. on .to the usual "bedding" Plane fr.actures, and fa'ult planes. T ]) ~ )1-73' Surface elevation of WW-3 was 1,800~, . . . Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 While waiting for core equipment to be used for coring ~-1, the rig was moved into location for WW-4. The well was sited 1200' North of the ice haul road between the airstrip and rock quarry in SW ~, Sec. 16, T23N, R28E This was essentially a "test hole" also and was drilled for drilling information that might be related to drilling of Doyon #3 oil well. The hole was drilled to 11' with a 7 7/8" rock bit, and 6" casing set on what must have been ice. As drilling proceeded, the casing tended to slip down the hole. The casing was pulled, and other casing driven to 17', with no further slippage problems. The hole was drilled to 260', where circulation .was lost. Two cores were taken composed of hard, gray limestone, with horizontal (lateral) fractures. The fractures were filled with calcite, limonite, hematite. WW-4 was abandoned at 273', and was later filled to the surface with crushed rock and cemented. Surface elevation of ¥~-4 was found to be 2,160'. 10 Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 A site was cleared of snow and brush at the con- fluence of two small intermittant streams in the SW corner of SW ~, Sec. 19, T23N, R28E, some 6,000' west of the drill pad for Doyen #3. The well. was spudded March 20. This was intended to represent our last effort to find water, and our plans were to drill to the depth capability of the rig. Additional drill pipe was flown from Fairbanks to allow us to drill to 84~'. Frozen muck and a peculiar yellow clay'with Coloration attributed to limonite was drilled between 39' and ~1' depths. Casing was set at 60' using 9 ~/8'" oilwell casing. Drilling proceeded with vari- colored carbonate rocks being drilled to a point Where circulation was lost at ~78'. The drill string came out muddy, wet and plastered with rock cuttings. A core was taken, revealing hard, gray limestone. A solution- widened fracture in the first foot of co:r'e (~79') was filled with water carrying minerals in solution. Upon drying, a white powder residue was left in the fracture. Attempts were made to clean the hole by injecting air and soap to .produce a drilling foam. No water was actually produced from t~is zone. Drilling was resined to a depth of 671'. The hole was allowed to stand for two day~~ s while equipment was repaired. A dry' drill stem was run in the hole, bottom was tagged, the drill string pulled out of the hole without circulating or rotating. Eo evidence of water was shown by the dry drill string except ~;or a small, insignificant wetness coinciding with th~ ~78' d~ptt~ where water was encountered initially. 11 Taylor Consul' ing Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 _~,~.. (cont'd.) A distinctive yellow, friable, carbonate residue stratum was drilled in this well, with the lower contact found to be at a depth of 300'. This. should correlate closely with what appeared to be the same zone drilled (cored) at a depth of ~60' in WW-2. (Surface elevations for comparison are: ~J-2 at 1,680', and WW-~ at 1,500'.) The formations drilled appear to represent what is reflected at the face of the rock quarry...jointed and fractured massive gray limestone, with fractures and joints stained with limonite and hematite, with some calcite filling of void spaces. WW-~ was sited some 900' northeast, and across a small stream, from the site of Core Hole #44, which is located in NW ~, Sec. 30, T23N, R28E. When it was realized that in order to make a useful water well at WW-~, if pursued to greater depth, a water-bearing formation wou].~, t~av¢~ to be drille~], water contained in said formation would of necess'~.ty have to be under considerable hydrostatic pressure to allow it to fill the hole some six hundred (600~), and a pump capable of lifting this water several hundred feet out of the hole would be required. Since casing off the lost-circulation zone was necessary in order to drill to expected depths, it was decided not to spend the $16,000. n~cessary for casing in the hopes of combining several unlikely events necessary to make a wa[~er well at this site. ~-~ was filled with rock and cemented to the surface. 12 Taylor Consulting Service 4705 Piper Street Anchorage, Alaska. 99507 907 274.2474 A site.was cleared 200' west of "Line #9" ' ~ and some 300' north of the small intermittant stream designated "Salmon-Trout", in the SW ~, Sec. 2~, T23N, R28E. The well was spudded April 2,~ten feet of frozen soil and peat was drilled and casing set at that depth. The hole was drilled in gray shale to a depth of 290', where a five-foot core was taken in dark gray silty shale, highly carbonaceous, and only traCes. of calcareous ~material. The finely divided cuttings had the appearance and texture of lignite, though this was not reflected in the core taken. The surface elevation of WW-6 was es.timated to be 1,~00'. The well was abandoned at a depth of 29~', ' and was plugged from 200', to the surface. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 Location was cleared of snow and brush some 400' northwest of the water-haul ice road crossing of the Salmon-Trout intermittant stream in the NE ~, Sec. T23N, R28E. Surface elevation 1500', spudded April 4- No surface casing 'was set. The hole was drilled in medium gray shale to a depth-of 94'. The hole was plugged top to bottom and abandoned. 14 Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 Permission was obtained from The Bureau of Land Management-to clear a site 80' x 80' adjacent to our water-haul ice road and the edge of the small lake currently supplying the water for the Doyon #3 con- struction project. This is located in NW ~, Sec. 30, T23N, R2.gE. The well was spudded April 7, and drilled in dark gray shale to a depth of 110', where water was found to enter the well-bore. The hole was drilled to 120'~ and the water flow tested at a rate of six gallons per minute ( 6 GPM ). This water was warm, and .smelled strongly of the odor of sulphur, and other minerals. The producing formation was loose, fractured/shattered almost-black shale. The water reflected the formation carrying it, foul and black. An attempt to core this zone failed when the core bit encountered fifteen feet of "fill" on bottom, and "jammed", with a baseball-sized chunk of dark gray shale found in the bit, the core barrel otherwise empty. This hole was abandoned,, but left open, for possible future use as an eraergency source of rig water. The surface elevation at this well site is unknown, but is astimat~od to be ~o~rla 1,~00'. Subsequont to tho failuro to obtain a core at water-bearing depth~ the hole was deepened with a tri- COhO rock bit to 23~', and abandoned. 'Water rose in the bore-hole to within 1~ feet of the surfaco, but several flow tests indicated ~-6 GPM~ maximum flow rate. Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 This shallow well was drilled alongside the rock surfaced haul road betWeen the rock quarry and the air strip. A small glacier was observed to be forming where the the roadway had been cleared. One foot of clear water was found under ~he snow, pooled up on uphill side of the forming glacier. The well was spudded April 8, casing was set at a depth of 18', drilling proceeded with a percussion bit. Considerable moisture was encountered at ~8'~ however, as drilling progressed the formation drilled proved to be hard, dry, gray limestone. The well was plugged and abandoned at 10~'. The surface elevation at this site should be about 1,9~0'. (The project was abandoned following the drilling of this well, the drill rig prepared for being flown to Fairbanks on Hercules aircraft.) 16 Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 SUMMARY AND CONCLUSION Nine (9) bore-holes were drilled at depths ranging from 94' to 695' for the purpose of providing a source of water for the drilling rig and camp during the drilling of the Doyon #3 oil well. No water was encountered in any well not attributed to melted, ice lenses, except that noted at a depth of ~78' in WW-~, and the 5-6 GPM flow tested at a depth of 110-120' ~n ~-8. Severe lost-circulation problems that may prevent routine drilling of the Doyon #3 oil well were encounter- ed in all wells on or near the drill site of Doyon #3. Ail holes either sucked in air, or expelled air into the atmosphere~ depending upon atmospheric pressurej after being drilled to depths where circulation was lost. This. appeared to result from extensive vertical "joints" in massive limestone being penetrated by the drill bit, with said joints leading to very large "voids" at depth. The voids~ which are pres~ned to be typical solu'~ion cavities formed in otherwise impermeable l~mestone, were not in themselves p~netrated by the bit in any well. The topography shows relatively little surface runoff in the general area, and it is expected that the bulk of the snowfall will simply sublimate into the atmosphere. It is possible that this snowmelt water will percolate downward through the jointed and fractured limestone to great depths before being trapped by any impermeable formations, and incorporated into any exist- ing "ground water". 17 Taylor Consulting Serwce 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 SUMMARY AND CONCLUSION (cent' d.) The remaining construction activities and drilling of the Doyen #3 oil well must depend upon water pumped or hauled from the lake in Section 30, T23N, R29E. This lake is located on land managed by the Bureau of Land Management. Permission has been granted to LL&E to construct a site at the lake shore where a wooden plat- form will be constructed to contain both pump and fuel tanks within an enclosure lined with an impermeable membrane. A surface pipeline will be laid along the existing ice haul road to cross the Salmon-~rout (a small, 'intermittant streara), continue along said ice haul road to the intersection of seismograph lines #9 and #20, continue northwesterly to intersect the ice haul road 0.6 mile east of the east end of the airstrip, continue alongside' the airstrip to facilities planned at the west end of this airstrip. From that point, it is planned to pipe the water downhill to the tempera.fy camp located on the floor of the rock quarry, thence on to the camp and drill rig on drill site Doyen #'3. It is presumed that an ice haul road will be con- structed next winter if drilling aontinues into cold weather which would prevent use of the surface pipeline. The lake water is acceptable, though discolored volu}nes of water stored in this lake can be given, as tho author does not know whore t]~o wate.r ~Lino ~Lios in this lake. However, taking a very con:]orva'givo c,'~timato (~0% of expected values) of the surface area, it appears that at loas'b 30 acre-foot of water is contained lake. 18 Taylor Consulting Service 4705 Piper Street Anchorage, Alaska 99507 907 274-2474 SUMMARY AND CONCLUSION (cont'd.) An acre-foot of water contains 330,000 gallons', giving a conservative estimate of ten (10) million gallons of water, with more expected to enter the lake due to snowmelt runoff. The shallow lake lies on hard shale, and no evidence of alluviam gravels was penetrated by the drill bit, as had been suggested previously. The camp and drilling operation should cons~e no more than 20,000 gallons.of water, daily avorag~.~ ~.£or even the most severe drilling-mud losses to the formation that could concievably be finacially supported for any appreciable length of time. On this basis, the existing water in storage at the lake should be more than adequate to support the operations at Doyen #3 for much longer than need be (some 400'~00 days). It is recommended that a filtration system be inCorporated at the camp to make this lake water more palatable, 'and mor~ attractive, for use as ca~p water, tt is, of course, perfectly suitable for drilling rig use as is. The failure of the water-well drilling program to locate useable well-water in the near vicinity of the drill site of Doyen #3 was a disappointment. The p~aping of water some six or seven railes via a surface pipeline is both costly and tedious. In view of existing conditions, there does not seem to be a more attractive solution to tho problem of supplying the nocossary water for tho proposed drilling operations. George W. Taylor April 18, 1977 19 LOCATED IN THE APPENDIX UI WFL UI IPR LOG UI CALIPER SURVEY UI VOLAN UI CURVE DATA UI STRATIGRAPHIC HIGH RESOLUTION DIPMETER Form 10-403 REV. 1-10-~73 Submit "1 ntentions" in Triplicate & "Subsequent Reports" in Duplicate STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE SUNDRY NOTICES AND REPORTS ON WELLS (Do not use this form for proposals to drill or to deepen Use "APPLICATION FOR PERMIT--" for such proposals.) O~L ~ SAS I"--I WELL I..;.;J WELL L--J OTHER 2. NAME OF OPERATOR The Louisiana Land and Exploration Company 3. ADDRESS OF OPERATOR 550 West 8th Avenue, Suite 202, AnchOrage 99501 LOCATION OF WELL At surface 2696' south and 1360' T23N R28E F.M. east of NW cor. Sec. 20, 13. ELEVATIONS (Show whether DF, RT, GR, etc.) 1794 surface 14. CheCk Appropriate Box To Indicate Nature of Notice, Re 5. APl NUMERICAL CODE 50-043-,20'002 6. LEASE DESIGNATION AND SERI/: 7. IF INDIAN, ALLOTTEE OR TRIBE Doyon, Ltd. 8. UNIT, FARM OR LEASE NAME Doyon~ Ltd. 9. WELL NO. #3 10. FIELD AND POOL, OR WILDCAT Wildcat 11. SEC., T., R., M., (BOTTOM HOLE Sec. 20 T23N R28E F 12. PERMIT NO. 77-27 ~ort, or Other Data NOTICE OF INTENTION TO: TEST WATER SHUT-OFF ~ PULL OR ALTER CASING FRACTURE TREAT H MULTIPLE COMPLETE SHOOT OR ACIDIZE ABANDON* REPAIR WELL CHANGE PLANS (Other) SUBSEQUENT REPORT OF: WATER SHUT-OFF [~ REPAIRING WELL FRACTURE TREATMENT~ ALTERING CASING SHOOTING OR ACIDIZING ABANDONMENT* (Other) (NOTE: Report results of multiple completion on Well Completion or Recompletion Report and Log form.) 15. DESCRIBE PROPOSED OR COMPLETED OPERATIONS (Clearly state all pertinent details, and give pertinent dates, including estimated date of starting any proposed work. Propose to plug and abandon Doyon ~3 well at T.D. 13,533' as follows: On bottom 100 sx. Class 'G. 8590-8155 - 152 sx.' Class G across shoe of 250' to surface, 150 sx. permafrost Install well marker 9 5/8" csg. Note: 9 5/8" csg. was set ot 8497.48' and was not pulled. No hydro- carbons were encountered in well. SEP 1 5 !fiX7 Division of Oil and (:l:~s C~.ms'~i'v~iori Ailch0ra!'l~ 16. I hereby certify that the foregoing is true and correct SIGNED ~~ ~ TITLE Project Manager DATE 9/13/77 (This space for State office,~se) APPROVEDBY ~~':';¢~L ~'~"~~ CONDITIONS O~'~PPROVAL, IF ANY: See Instructions On Reverse Side ,, L Form No. REV. 3-1-70 SUBMIT IN DUPLICATE STAT E O F A LAS KA OIL AND GAS CONSERVATION COMMITTEE MONTHLY REPORT OF DRILLING AND WORKOVER OPERATIONS 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND SERI/ 1. 2. NAME OF OPERATOR 8. UNIT FARM OR LEASE NAME The Louisiana Land and Exploration Company Doyen, Ltd. 3. ADDRESS OF OPERATOR 550 West 8th Ave., Suite 202, Anchorage 99501 #3 10. FIELD AND POOL, OR WILDCAT 4. LOCATION OF WELL Wi ldcat I 11. SEC. T. R. M. (BOTTOM HOLE 2696' south and 1360' T23N R28E F.M. 7. IF INDIAN'ALOTTEE OR TRIBE N'fAMEi Doyen, Ltd. I east of NW cor. Sec. 20 12. PERMIT NO. 77-27 13.REPORT TOTAL DEPTH AT END OF MONTH, CHANGES IN HOLE SIZE, CASING AND CEMENTING JOBS INCLUDING DEPTH SET AND VOLUMES USED, PERFORATIONS, TESTS AND RESULTS FISHING JOBS JUNK 1N HOLE AND SIDE-TRACKED HOLE AND ANY OTHER SIGNIFICANT CHANGES IN HOLE CONDITIONS. 9/1/77 9/10/77 9/13/77 TD 12,353' TD 13,533'. Logged and prep. to P and A P and A. TD 13,533'. Set plugs as follows: Bottom plug 100 sx. Class G 8590-8155. well marker. Class G. Across shoe of 9 5/8" csg. 152 sx. Top 250' with 150 sx. permafrost. Installed 14. I hereby ~t the foregoing i~j~/~e ~and correct SIGNED TITLE. Project Manager · DATE 9/13/77 NOTE--Report on this form is required for each calendar month, regardless of the status of operations, and must be filed in duplicate with the oil and gas conservation committee by the 15th of the succeeding month,unless otherwise directed. THE LOUISIANA LAND AND EXPLORATION COMPANY SUITE 202 - 550 WEST 8TH AVENUE PI~ONE (907) 276-7545 ~INCHORAGE, ~ILASKA 99501 September 12, 1977 State of Alaska Division of Oil and Gas 3001 Porcupine Drive Anchorage, Alaska Re: Doyon ~3 Final Mud Logs Kandik Basin, Alaska Dear Sirs: Enclosed you will find one (1) copy of the Doyon #3 final mud log plus sepia. Please acknowledge receipt by signing and returning a copy of this letter. Yours very truly, THE LOUISIANA LAND AND EXPLORATION COMPANY Lawrence Davis Project Manager LD: lgh Enclosures Received this /~,~/ day Form No. P-4 REV. 3-1-70 SUBMIT IN DUPLICATE STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE MONTHLY REPORT OF DRILLING AND WORKOVER OPERATIONS 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND 7. IF INDIAN.ALO'H EE OR TRIBE IqAMI~ 8. UNIT FARM OR LEASE NAME Doyon, Ltd. 10. FIELD AND POOL, OR ~IL~T Wildcat ~. s.c. ~... ~. ~.o~o~ .ou~ OBJECTIVE) Sec. 20~ T23N 1. 2. NAME OF OPERATOR The Louisiana Land and Exploration Company 3. ADDRESS OF OPERATOR 550 W. 8th Ave., Suite 202, Anchorage, Alaska 99.501 4. LOCATION OF WELL 2696' south and 1360' east of NW cor. Sec. 20 T23N R28E F.M. 12. PERMIT NO. 77-27 13.REPORT TOTAL DEPTH AT END OF MONTH, CHANGES IN HOLE SIZE, CASING AND CEMENTING JOBS INCLUDING DEPTH SET AND VOLUMES USED~ PERFORATIONS, TESTS AND RESULTS FISHING JOBS JUNK IN HOLE AND SIDE-TRACKED HOLE AND ANY OTHER SIGNIFICANT CHANGES IN HOLE CONDITIONS. 8/1/77 8/11/77 8/14/77 8/15/77 8/31/77 TD 6967'. Drilling 12 1/4" hole. TD 8539'. Logging in preparation to run 9 5/8" csg. TD 8539'. Set 9 5/8" csg. to 8497'. Cemented with 750 sx. Class "G". Tested float equipment. TD 8539'. Drilled, cemented, tested 9 5/8" csg. to 2500 psi (okay). Began drilling ahead. TD 12,353'. Drilling 8 1/2" hole. 14. I hereby ~e~!i,fy_~ the foregoing is,tr~,~,~ and correct SIGNED, ~ TITLE Project Manaqer DATE September 8, 1977 NOTE--Report on this form is required for each calendar month, regardless of the status of operations, and must be filed in duplicate with the oil and gas conservation committee by the 15th of the succeeding month,unless otherwise directed. Form 10-403 REV. 1o10-73 Submit "1 ntentions" in Triplicate & "Subsequent Reports" in Duplicate STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE SUNDRY NOTICES AND REPORTS ON WELLS (Do not use this form for proposals to drill or to deepen Use "APPLICATION FOR PERMIT---" for such proposals.) O,L ~ GAS r-] WELL L~,~J WELL OTHER ~ NAME OF OPERATOR The Louisiana Land and Exploration Company 3. ADDR~S OF OPERATOR 550 West 8th, Suite 202; Anchorage, Alaska 99501 4. LOCATION OF WELL At su dace 2696' south and 1360' T23N, R28E F.M. east of NW cor. Sec. 20, 13; ELEVATIONS (Show whether DF, RT, GR, et~) 1794 surface 14. Check Appropriate Box To Indicate Nature of Notice, Re 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND SERIAL NO. 7. IF INDIAN, ALLOTTEE OR TRIBE NAME Doyon, Ltd. [8. UNIT, FARM OR LEASE NAME Doyon, T.td. 9. WELL NO. #3 10. FIELD AND POOL, OR WILDCAT Wildcat 11. SEC., T., R., M., (BOTTOM HOLE OBJECTIVE) Sec. 20, T23N, R28E F.M. 12. PERMIT NO. 77-27 )ort, or Other Data NOTICE OF INTENTION TO: TEST WATER SHUT-OFF FRACTURE TREAT SHOOT OR ACIDIZE REPAIR WELL PULL OR ALTER CASING MULTIPLE COMPLETE ABANDON* CHANGE PLANS (Other) SUBSEQUENT REPORT OF: WATER SHUT-OFF ~ REPAIRING WELL FRACTURE TREATMENT ALTERING CASING SHOOTING OR ACIDIZING ABANDONMENT* -, (Other) (NOTE: Report results of multiple completion on Well Completion or Recompletion Report and Log form.) 15. DESCRIBE PROPOSED OR COMPLETED OPERATIONS (Clearly state all pertinent details, and give pertinent dates, including estimated date of starting any proposed work. Change proposed total depth from 12,000' to 14,000'. No additional casing planned unless hole conditions dictate. 3.6. I hereby certify that the foregoing is true and correct SIGNED. TITLE Project Manager DATE August 23, 1977 (This space for State office use) OtF,_gppI~O~AL' . - . TITLE ,- .... " r,,..-J . -- ,,r~ DATE . · ~e Instructions On Revere Side ~ Form No. P-4 REV. 3-1-70 SUBMIT IN DUPLICATE STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE iONTHLY REPORT OF DRILLING AND WORKO¥1ER OPERATIONS 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND SERIAL NO. 1. 7. IF INI)IAN'ALOTTEE OR TRIBE NAME OiL GAS [--! 2. NAME OF OPERATOR 8. UNIT FARM OR I.EASE NAME The Louisiana Land and Exploration Company Doyon, Ltd. 3.ADDRESS OF OPERATOR 9.WELL NO. 550 W. 8th Avenue, Anchorage, Alaska 99501 #3 4. LOCATION OF WELL o 2696' south',and 1360' east of NW cor. Sec. 20 T23N:'R28E F.M. , 10. FIELD AND POOL, OR WILDCAT Wildcat 11. SEC. T. R. M. (BOTTOM I1OLE OBJECTIVE) Sec. 20, T23N R28E F.M. 12. PERMrr NO. 77-27 13.REPORT TOTAL DEPTH AT END OF MONTH, CHANGES IN HOLE SIZE, CASING AND CEMENTING JOBS INCLUDING DEPTIt SET AND VOLUMES USED, PERFORATIONS, TESTS AND RESULTS FISHING JOBS JUNK IN HOLE AND SIDE-TRACKED itOLE AND ANY OTHER SIGNIFICANT CHANGES IN HOLE CONDITIONS. 7/]./77 7/2/77 7/3/77 7/4/77 7/5/77 7/6/77 7/7/77 7/8/77 7/9/77 TD 2331' - Mix 50 BBL diesel with 100 sx. gel, pump 300 BBL water; 5 BBL d.iesel, 50 BBL diesel with 200#/BBL gel. Drill pipe on vacuum. Spot another 50 BBL diesel with 200~/BBL gel. Drill pipe still on vacuum. Mix 50 BBL water with 50#/BBL caustic, 10 gal. RD-21 complexer, 2 BBL water, 75 BBL water with 40#/BBL pronto plug, 2 BBL water, 10 gal. RD-21 complexer. Mix and displace 2nd 75 BBL pronto plug as above. TD 2331' - Mix and displace 640 sx. pronto plug. 250 sx. Class "G" with 3% cacl. WOC.. Pump 100 sx. calseal WOC, pump 2 more 100 sx. each calseal plugs. TD 2331' - Pump total 600 sx. calseal. TD 2331' - Pump 200 sx. calseal, 100 sx. Class "G" with 3% cacl, mix 2nd 250 sx. Class "G" with 3% cacl. Perfs are plugged - test perfs and are holding. TD 2331' - Open FO tool - pump total 1003 sx. permafrost. TD 2331' - Pumped 334 sx. permafrost through FO tool. Displaced 334 sx. between 20" and 13 3/8" annulus. Mix 200 sx. calseal and displace in annulus. Cut hole in 20" csg. Put 8 yds. crushed rock, 5 sx. fiber, 25 sx. nut plug and 100 sx. calseal in annulus - circulated cement - welded csg. TD 2331' - Drilled cmt. retainer. Tested 13 3/8" csg. with 500 psi. TD 2331' - Drilled out shoe. Pressured up to 450 psi - would not hold. Recemented shoe with 100 sx. Class "G" with 2% cacl. TD 2331' - WOC and retested shoe. All okay -.began drilling. 8/1/77 TD 6967' - Drilling 12 1/4 hole. 14. I hereby certify that ~e foregoing is true a~O correct TITLE Project Manager .... DATEAUgUSt 3, 1977 NOTE--Report on this form is required for each calendar month, regard!ess of the status of operations, and must be filed in duplicate with the oil and gas conservation committee by the 15th of the succeeding month, unless otherwise directed. Form No. REV, 3-1-70 SUBMIT IN DUPLICATE STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE ON. THLY REPORT OF DRILLING W'OR OVE oPERATIOiqS 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND SF. RIAI. NO. 1. 7. IF 1NDIAN'ALOTTEE OR TRIBE NAME OiL [] GAS [---] Doyen, Ltd WELL WELL OTHER 2. NAME OF OPERATOR 8. UNIT FARM OR LEASE NAME The Louisiana Land and Exploration Company Doyen, Ltd. 3. ADDRESS OF OPERATOR 9. WELL NO. 550 W. 8th Avenue, Anchorage, Alaska 99501 #3 4. LOCATION OF WELL ~ Y' i.-~ i *f ~L 2696' south and 1360' east of NW cor Sec. 20 T23N R28E F.M. 10. FIELD AND POOl., OR WILl)CAT Wildcat 11. SEC. T. R. M. (BOTTOM ttOLE OBJECTIVE) Sec. 20, T23N R28E F.M. 4~0~RMl'r NO. 77--27 13.REPORT TOTAL DEYFH AT END OF MONTH, CtlANGES IN HOLE SIZE, CASING AND CEMENTING JOBS INCLUDING DEPTIt SET AND VOLUMES USED, PERFORATIONS, TESTS AND RESULTS FISHING JOBS JUNK IN HOLE AND SIDE-TRACKED IlOLE 3aND ANY OTHER SIGNIFICANT CHANGES IN HOLE CONDITIONS. 5/29/77 Set 30" csg. @ 51' RKB. Cemented with 255 sx. permaf, r~st. 5/30/77 Lost cement to formation. Recemented with total 475 sx. permafrost - cemented to surface. Spud 9:00 p.m. 6/3/77 Set 94# K-55 20" csg. at 194' and cemented with 595 sx. permafrost. 6/20/77 TD 2329' logged in. Prep. to set 13 3/8" csg. Fluid level in hole 882 6/21/77 TD 2329'. Set 2296.31'. 72# N-80 13 3/8" csg. with Halliburton FO tools @ 656' and 498'. 6/22/77 Mixed and pumped 1150 sx. permafrost and 580 sx. Class "G" - ran Camco temp. svy. No cement outside csg. 6/23/77 Mix 430 sx. Class "G" - ran Camco temp. svy. Temp. rise 50° @ 1500' to 66© at 2080'. 6/25/77 Finished nippling up and tested BOPs, etc. Perforated 13 3/8" csg. @ 1875' with 4 shots over 1' interval. Set Halliburton EZ-SV cement retainer @ 1834' - squeezed 210 sx. Class "G". 6/26/77 WOC and ran Camco temp. svy. Indicated cement. Perforated 13 3/8" csg. @ 1575' with 4 shots over 1' interval. Set Halliburton EZ-SV cement retainer - squeezed 575 sx. permafrost. 6/27/77 Ran temp. svy. - no cement. Mix 500 sx. permafrost with mica - perfs on vacuum when complete. Mix another 500 sx. permafrost with mica - vacuum on DP after complete. 6/28/77 Pumped 40 BBL diesel mixed with 100 sx. gel, followed by 250 sx. Class "G" with 3% cacl. DP still on vacuum. Spotted second 45 BBL diesel gel mixture. 6/29/77 Pump 40 BBL'diesel with 100 sx. gel. Still on vacuum, spot second 40 BBL diesel with 100 sx. gel. Still on vacuum, spot third 40 BBL diesel with 100 sx. gel. Still on vacuum. 6/30/77 Mix 550 gal. sodium silicate tailed with 250 sx. Class "G" with 25#/sx. gilsonite and 4% gel and 2% cacl. Still on vacuum. Spot 50 BBL diesel with 100 sx. gel, spot another 50 BBL diesel with 100 sx. gel followed with 250 sx. Class "G" with 25~/sx. gilsonite and 4% gel and 2% cacl. Still on vacuum. 14. I hereby certify that. the foregoing is trugand correct '~J' Z Ai? TITLE Project Manaqer DATE July 18~ 1977 SIGNED '* ~ ~ ~-~ ............ , ~-'/"~'~ ~ , NOTE--Report on this form is required for each calendar month, regardless of the status of operations, and must be filed in duplicate with the oil and gas conservation committee by the 15th of the succeeding month,unless otherwise directed. 02..001B STATE of ALASKA DEPA~m~ OF ~~AL R~qOURC~ Divisio~ of Oil and Gas Com~~~ TO: [-- FROM: O. K. Gini, Jr. D~ Ben ~mn Petroleum Inspector DATE : SUBJECT: July 12, 1977 F~pl~rati~n Doyc~ #3 ~sday~__ Juqe~ _23, ~ - I departed my ~ at 7:15 AM for a 7:45 f94 '~ ~ ~cipated 8:00 ~ ~e ~ ~~ ~ ~ ~ L.L.~.'s ~ ~3 ~~a~ly 25 ~~ ~st of C~le, A]~. ~ d~~ ~e ~~~~ .~ at 8:30 AM ~ ~iv~ at ~ ~ %3 ~~ip at 10:40 ~. ~s ~ip ~ pr~ipi~t by a 6:00 AMp~ ~1 f~ L.L.&E. ~i~ Y~ ~ ~ ~i~ ~ At Parker Fig ~147's camp w~ cc~~ Bob Ramsey, ccnsulting drilling foreman, ~qd tool~ Mike Ba~. 13 3/8" c~~ w~s being hung and r~ppling up w~uld begin c~ ~ipt of a four foot spool to get the cho~ ~ kill line c~nnecticms above ground level. Bob ~y advised 13 3/8" surfaoe p~e was set at 2302' v~th F.O.'s set at 656' and 498'. A basket was set tw~ joints below eac~h F.O. Temperature ~s indicated c~m~nt ~ ~he shoe to 2085' where a lost circulaticm zone prc~ably exists. ~ ao/v~ ~h~y w~ald at+~mpt, to c~ment to the. ~le awaiting nippl~ up, I ~ the location whid~ was v~ll c~gar~zed, th~ reserve pit w~ll built, steel %~~. ~ tanks benm~ and lined, the rig in ~ repair and no rig sign in evidence. P~ advised a sign %~uld ~ or~ ~iately. H~ also adv~ ~n igniter has been ordered f~r installatic~ on ~ blooie lir~ ~ the event gas zones are encount~ Ln ~s air drilling c~rati~n. Nipp~ up ~ d~tayed ~ the 13 3/8" packoff ~ald not test and a special flight called f~£ d~ii~ frc~ Anc~.~e. T~sting ~uld be dome with acctm~tor pu~ and ~ter. · ~00-I~l.- ~ pl~ ~_re flying dura to visibility bel~v FAA ntinimums. Tests ~ at 12:00 n~Dn %~ith upper pipe ra~s, inside vmlve cm the k~l lin~ ~nd inside val~ ~n the choke line tested to 5000 psig. Hydril ~ testa~t to 2500 psig. ~ pipe ra~, HCR %~lve cm the chc~ line and HCR vnclve on the kill lir~ tested~ ~ 5000 psig. Blind ra~ ~. ~k %~lve in tP~ kill ~ tested to 5000 psig. Doyon ~3 -2- July 12, 1977 E~ vales ~d eighteen flanges in the choke manifold tested to 5000 psig. ~ su~ was actuated fully opened and fully closed and manual adjustable choke was free moving. Aoc~m~/a~ pressure %~s 2700 psig.~N9 ~]y.--k~ap bottles ~e~ to 2100, 2000, 1950, 1600, 1900 and 2000 psig. ~ ar~ ~ kelly valve tested to 5000 psig. Both dart ~ ar~ ball ~]pe flo~r val%~s ~e in place. Tests were co~cl~ at 4:30 ~ ~ a field inspection reT~ prepared with the ~riginal given to Bob Ramsey, a ~ ~ to ~ Davis and a oopy attached to I de~ the locati~ via L.L. ~. ~ Volpar at 5:10 PM and arrived ~ Fairbanks at 6:20 PM. I de~rtsd Fairbanks at 7:35 PM via Wien flight #104, arriv~ in ADx~ora~e at 8:25 ~ and at my hcme at 8:55 ~: I ~i~sed successful BOP~ ~ on L.L.&E. 's Doyon ~3. At~t STATE of ALASKA DEP~~ OF ~TURAL R~X~CE~ Division of Oil and gas Consexvation TO.. J--'- FROM: O. K. Gilbreth, Jr. Director . Hoyle H. [~uil~ . /~//,/~ Petroleum ~ DATE July 7, 1977 SUBJECT: Inspect Air Drilling .Operatio~ Louisiana Land and. ~_~xploration' s Doyon #3 %R~e~v, June 8, 1977 - I de~ rm_F bx~n~ at 7:00 ~ for a 7:30 ~- a~--~~ 8 {00 ~4 ~e v~ ~~~ ~~ for L.L. ~.' s ~ 93. ~ ~~~~e ~~~~ at 9:00 ~ ~ ~i~ at ~ 1~~ at 11:00 ~ I ~ ~ ~ ~~~ Da~s, L.L.~. ~~~r, ~ ~ ~~ick, ~~ ~1~ f~~. ~i~g ~~ is P~~ ~~ ~g ~147. ~ ~~ is ~~- ~ly ~ ~s ~ of ~ ~~ ~~ ~ ~5 ~les ~~t ~cle, ~~. Air for t~J.s ~ drillin~ cgerati~ is furni~ by three prima~3 Den~_r ~sors %~th two ~ cc~pres~s in series. Vol~ is 2000 CFM @ 200 psi. Currently 48 GPD of soap is being injected in a water solutio~ into the air stream due to lost circulation probl~s. Circulation was lost at 600' and dur~ ~/ i~+_io~ rig was makin~ hole bel~g 1200' with no returns. ~amic Pic~r~re 1,~. 1 shows the drillir~ pad witch the camp, rig, flare pit and degasser. Pi~cu~e ~k). 2 taken fr~n the aircraft, shows the drill~j pad, construction ~,-~-=~strip. Picture k%. 3 shc~s ~he ~ee C~r~- D~a~r pr~ ccmlaressc~s with th~ t~o'~~res~s in series and the ~ ar~ ~ter injection unit. The ~_ion frc[a the ocr~presscms ~ injectic~ unit to th~ standpipe is just above the floor. A bypass (Picture No. 4) is manifo~ into ~ standpipe wh~ actuation of ~o va~IveS--~ ~ss t/~ air to the blooie line ~ile makin~ connections. A kelly bleedoff line (Picture ........ ~.~. 4) is co~a%ecte~ to th~ standp~.ne just ~ th~ bypass to bleed pressure freD. the kelly ~ile ~3dng connectix. A bit sub in-the d~i!l col!_ar string has ~ drille~ for a baker float valve to prevent cuttings frc~ reversing up th~ drill pipe v~ile ~ is dive~ed to t~w~ blooie line while n~king oonn~ction~. A ~ant rota~ drilling ~ (Picture No. 5) is uti!ized~ %0 close ~ syste~. ~ blooie ~ origina~ at-the -drilling he~] and ~t~. in the ~ pit (F_i~ .c~ ~_ I.~9, 9) is 6" ID by at~t?ly 250' in length. ~ gas sp~~ is loCa~ad--~ ~lf-way and is routed into the ~obil lab (Pi~ No. 6)..The sampler (~icture No. 7) is located jumbo cn the ~ 5r-=the r~_~e p~t. The dmdus~-i~~ ~10~~ ~_ cy~imately 30' }~fore temmination of t~ lin~ (Picture No. 8). Gene Bazmon, conm~lting drillin~ fore~.~, advised a pilot a~d~or '.~~or would be installed, at the blooie ~ o~tput after 13 3/8" is set at 2500'. Doyon 93 -2- Jttly 7, 1977 ~ ~s are currently filled wi~h w~ter and rig mud p~nps ar~ mud available in case ~ need ~o mud up. The degasser is mounted outside ~ ~acture and all ~sary manifolding and bypass ccatnections to the f~_are pit are nmde in ~ of need. Nine water ~ holes ware drilled ~_th no water shows. ~ater is heing~ piped fr(xa a lake loca~ s~4~n miles away. Since freez/ng of this line would halt dr~ activity during that inter~ period when water trucks e~g~s caloalate oDly the ~ two or three feet will freeze and that Bo~h Lawrence Davis and ~ Chadwick advised penetration rates have incr~ 1 1/2 to 2 1/2 ~ ov~_r rates experienced o~ Doyon #1 and #2. order to ~ better oc~e life. Idde~ the locatJnn at 3:45 PM arriving ~ Anchc=aoje at 5:45 PM ~ at my hc~e at 6:15 PM. ~: I witnessed air drill/i~ op~~~ at Louisiana Land and ~loratzon: ~-~'s ~ ~3 and found safe and efficient drilling practices '~.~ · Field InsPection Report !i~i~ii~!g.-.':.¥ .P.'.~::~m:~=:..t..~,,.,;~O.;:~'i~?.:..,. ':.. ..... '~::'.'....... ........... .....' .'..., .... ....... '...? ~i~'.~aj ...' ..... we,l,1/]~ SecJ~,$~IJR~~..M · Re? s 9 ed ,ame& umbe "- .:T' 'sati'sfactor. · 'T'. ~.,~,..]... .... ,,.,.~. .......... ,.....~',~ .......... ,[~]~.,...~~.]On.',.. , . ... S~.:i..stac~o~y Type,.Inspectio.n. = ' .... · ":Y.'"~eS'"""~'No.'"~'~'.~'~:L~.a't:i6n,General' Yes "No Item (~B.OPE Tests · ~..' · ..~,~'~,~?..~,,F-~...,..' ........ '....,.. ~.. .. . .' (.~. ( ) .~ ·ng set ~ .' · ,.. · ;':~]~..~.." ~".'~'.)~,.~.:~;...::.'".~.:~ .:?'n~.al...~ous~k~ep,,~ . ....' .(~() .16. ~f'luid-(~.t~)mud ('.').oil ~'T.~' k~'.t ~ ..~ ..'~eserve vit ( )open( )filled (~ ( ) 17 Master Hyd Control Sys s~a ~ [~m[~ ~ ] .... (~ m m (mm' ])m m m mm: m m m 'mm4m'm:m '~:'mm"]~ [~[ ]~ ~:~mmmm m]]m''~ ] m~m mm :~ ]imm m m ]m~ m mm m m mm mmm mmm] ] .... [ mmm m mJmm mm (:~mm m (')mm m m m 1 8 ; Nm2m ` ~ ~ lm S j] ; .,~m j~ ~~'m~ ~ "~.'~]':~:':' ( ) ( )'. 5;~. ~u.r~.Ce,No', Well~..' . (~ ('.) 20. Drill'ina. spool~ ..~ "outlets' (")' (')". '' we"il'S-.'. ' '(~ ( ) 21. Kill Li~e-(.~C~valve'.. . ~;?~?" ~ ' /"' ' 7 "~'""(""~')'""~el~" lest[Data ~ ' '(~ ('') 22..Choke FlOwline (~HCR valve ' . :;.....) .(. ~.( ..'...~ell..~.,~s..- ,. · ,'.. ,' '.. (~ (').' 23. ChOke Manifold No.. valv~ flas~ ::.~:...~ ~ ~..~. '. ~..."..~r.s~.-oDser.' · .... , , .-,. . .(~.'(' ) 24, Ch.okes-(~ote( )PoS.(~dj'.] · ... '... ~ ? .~.' ~. '.. 9., ~B.S&W '. . ,--,~, ...' .. "(~ ("..') 25. Test Plua-.(~'ellhd( )cs~( ),One · .: { ) (.) lO...Gr.;...'Bbls. . , ,. .', '.'(~ ( ) 26. Annular ~reventer~s~a' :.' '.' ' "'. .'.'. ". .': '.":~.(:~-~?'~Fin.a~a~m~n.~.'~ .. (~'.(') 27. Blind' Rams~psi2"" ' .... "~ '" · ':;."."'": ='[' ..: ('. '.)' '.. '('.'.:~]')' '".".". '] ml'..~''.].P~;~'~"~.~'~'" [] ;'.'.:,[.'. :'..'..."'" ."--.'--' ":'.' ": ':,:[". :]~'.,:~''.','.....' '; ".:]']~'[(~:~'~.~.~':. :')" ']'. 28'.:' ';'pi.pe '."Rarest.' ~;'s.{".q]~ ." '" .....~;]':;~':?"',.':~'~":". ," '..?"' ~". :"~ ~' ~'.~..,.... '].~..~;~:.~'well-(, ).cQp.ped( )..plugged' (.. ~ ( ) .2.9. 'Kelly'&.. Kel.l.y-c.oCk~y~.ps~'~]>~:.. .~' ~'.':5:'..:~' :~]'",';~"~ .... ~"J', "'.'b'~!'e~?.UP .'.. '] "" :". ,. '. '.~ .'.:.:.. .... · ';: ."'(':~'~.]. (..)' '.: '"30;' .LoWer. Kel.lY Val'v~pS:ig'~]'":?..'. :'~[~,;..' ,..:"':':'. '. · ." T~'~'~~m'" ":,~."~"~"~L ~ ,]"~'~__"'~?:,:q'ev::?.]";ed ':.'.;~'...~. :';':'.~'e~']~]'.".;..' ]' ~'.'.:~;.:~..':'..,~"~"m~(]i"""'")..""~''31".' '. safe ty .' 'Fl :oo r" 'va'i~.~~ '~:.'~ ~a~r.t ".. ...... ".. ~.~,... :.:-~:~:~,.un oDse;~va.~lon'.'..~lme~h.rs/~..'.lOtai..'.'numoer leaks and/or eaui' ' failures ....~:x........;~(.- ... · 'R .............. '~"" · · ' ............ · .... · ........ · ..... P' ': ' .... ~ '" ...... ' ..,,.' ~ar. Ks~<::~.i...:, . . ' '" ' ..... ".. '. "' '.. :.'.' ':.'"":."...'..' ".~', ' ':" .' "?. ...... ' .. ' · '. · · ' . ... ' ....:.'~:::.:..' ':.::,:7.':' :. '..., .. .]'.,:?... ~'..'.'?"..,..:::..:~.?...?-. ,.. · ...... ~--... ].....,.. ...,.'::'..'........,~, . ,. .............. ~..... .. · . .' . '. . · .'. , . ~ .'" :. ,:'. .... .' '~.~;:~?,'.,<.;'. . · .;: ' . , . .' '.. . ..... ..' .....'.. -.. ~'". ...... ' .; '~ . ~1-' ' ,:_.: .'_ .~ ' . . ' . , ..~, ..'....':.: .... :'.' ,.'.~: . , ' ,,~ . Form 10-403 REV. 1-10-73 Submit "Intentions" in Triplicate & "Subsequent Reports" in Duplicate STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE SUNDRY NOTICES AND REPORTS ON WELLS (Do not use this form for proposals to drill or to deepen Use "APPLICATION FOR PERMIT--" for such proposals.) 1. OIL ~ GAS WELL I.-~J WELL L--J OTHER NAME Of OPERATOR The Louisiana Land and Exploration Company 5. APl NUMERICAL CODE 50-043-20002 6. LEASE DESIGNATION AND SERIAL NO. 7. IF INDIAN, ALLOTTEE OR TRIBE NAME Doyen, Ltd. 8. UNIT, FARM OR LEASE NAME Doyen, Ltd. 3. ADDRESSOFOPERATOR 9. WELLNO. 550 West 8th, Suite 202; Anchorage, Alaska 99501 #3 10. FIELD AND POOL, OR WILDCAT Wildcat east of NW cor. 4. LOCATION OF WELL At su ~ace 2696' south and 1360' T23N, R28E F.M. 13. ELEVATIONS (Show whether DF, RT, GR, etc.) 1794 surface Sec. 20, Check Appropriate Box To Indicate Nature of Notice, Re 14. 11. SEC., T., R., M., (BOTTOM HOLE OBJECTIVE) Sec. 20, T23N, R28E F.M. 12. PERMIT NO. 77-27 )or~, or Other Data NOTICE OF INTENTION TO: TEST WATER SHUT-OFF FRACTURE TREAT SHOOT OR ACIDIZE REPAIR WELL PULL OR ALTER CASING MULTIPLE COMPLETE ABANDON* CHANGE PLANS ' (Other) SUBSEQUENT REPORT Of: WATER SHUT-OFF ~ REPAIRING WELL FRACTURE TRFATMENT ~ ALTERING CASING SHOOTING OR ACIDIZING ABANDONMENT* (Other) (NOTE: Report results of multiple completion on Well Completion or Recompletion Report and Log form.) 15. DESCRIBE PROPOSED OR COMPLETED OPERATIONS (Clearly state all pertinent details, and give pertinent dates, including estimated date of starting any proposed work. Change setting depth and method of cementing 13 3/8" csg. as follows: (1) Change setting depth to 2300' from 2500' due to hole deviation and lost circulation problems. (2) Lost circulation encountered 611'. Fluid level at 882'. Set F.O. tools at 682' and 500' and metal petal baskets when setting casing. Cement around shoe in conventional method with enough volume to cement to surface. If cement does not circulate to surface open bottom F.O. tool and circulate with air or water until cement sets. Ran temperature survey, locate first stage cement. Circulate cement through bottom F.O. tool with enough to cement to surface. Ran temperature survey, locate top cement. Open top F.O. tool, circulate cement with enough to cement to surface. If will not circulate to surface re-cement top through string in annulus. Drill out shoe~?~s~q~i~t to equivalent 16#. Squeeze if cement will not hold. hereby certify .~h;a~fi'~:~regoing is true and correct SIGNED "~"-~-~'~' TITLE Project Manager DATE June 20, 1977 (This space for State office use) CONDITIONS OF APPR05AL, IF ~Y: I ,. TITLE See Instructions On Reverse Side ..~7 ~y ~f, 1977 550 W. 8~ Avenue, Suite 202 An~age, bla~ 99501 Em~losed is ~ a~ applicatic~ for permit to drill the above referenced w~ll at a lc~ation in S~c~ 20, Town~hip 23~, Range 28E, FM. ~11 ~les, core chips ~ a mud log. are required. A directic~l survey is not ~. ?Z~ny rivers in D2Laska ~ t~h~_~r drainag~ s~ have been class~i~ as important for ~ spawn/n~ or ~gration of anadrcmcus fish. Operations in th~_se areas are subject to AS 16.50.870 and the regulations promulgated th~re~ (Title 5, ~ ~strative Code). Prior to cc~m~cin~ op~_rations you ~ ~ cor~;K~ ~_ed ~I the t~3bitat Coordinator's office, Depart- ment of Fish ~ Ga~. ~lluticn ~ any waters of t~e State is prohibited by kg 46, Chaut~r 03, Article 7 ~ ~ regulations ~gated thereunc~_r (Title 18, Alaska ~strative ~, Chap~_r 70) and by the Federal I,.~ter Pollution Control ~, as ~. Prior ~ cc~a~nc~ operation, s you ~ay be contacted by a representative of the De~ of En~tal Cc~servaticn. ~suant to ~ 38.40, ~ Hinge ~ State Leases, the Alaska Department of ~ is ~ notif]~ed ~ the issuance of this pezmit to drill. notified after ~ 20" casing.~ is ~n~ so that a representative of this Divisi(m ~ ~ early stable foam drilling operatims~ and a~ain when the 13 3/8" casin~ is to be c~z~nted so our r~presentative my be present to witness c~en~.~, as well as testing of blc~ut preven~ equiFment before ~ 13 3/8" cas'Lng ~ is drilled. L. Davis -2- In as ~ as ~s ~11 is utilizing a drilling tedmique unique ~o Alaska at ~his time, we will ~ %'~_; ~].ed reports of drilling operations sul~it~ed o~ Forum P-4, ~m~kly ~ of D~illir~ and W~r~ Operaticms, In the event of suspep~i~ or mbandomm~nt please give this office adequate ~ notificatic~ so that we may have a witness .present. Very truly yours, ~le H. ~1~ Enclosure De~t ~ Fish and Gane, tlabitat Section w/o encl. Department of Env~tal Conservation w/o encl. De~t of ~, Supervi~, Labor Law Cn~lianoe Division w/o encl. THE LOUISIANA LAND AND EXPLORATION COMPANY SUITE 202 - 550 WEST 8TH AVENUE PHONE (907) 276-7545 2kNCHORAGE, ALASKA 99501 May 17, 1977 State Division of Oil and Gas 3001 Porcupine Drive Anchorage, AK 99501 RE: Permit to Drill - Doyon #3 Well Kandik Basin, Alaska Gentlemen: Enclosed you will find the referenced permit along with a check for one hundred dollars ($100.00). We hope to be ready to spud the first week in June. We request that all information from this well be kept confidential. If you have any questions, please let me know. Yours very truly, THE LOUISIANA LAND AND EXPLORATION COMPANY Lawrence Davis Project Manager LD/bj s Enclosures RECEIVED i 8 Form 10-401 REV, 1-1-71 STATE OF ALASKA OIL AND GAS CONSERVATION COMMITTEE PERMIT TO DRILL OR DEEPEN la. TYPE OF WORK b. TYPE OF WELL OIL WELL [-~ DRILL GAS DEEPEN I--] 2. NAME OF OPERATOR SUBMIT IN TRIPL~ .£ (Other instructions on reverse side) SINGLE MULTIPLE THE LOUISIANA LAND AND EXPI.ORA~TO~ CO_Mi~_ANY 3. ADDRESS OF OPERATOR 550 West 8th Ave., Suite 202, Anchorage, AK 4. LOCATION OF WELL Atsurrace 2696' south and 1360' east of NW cor At proposed prSodezoCne. 20 T23N R28E F.M. 99501 API No. 50-043-20002 6. LEASE DESIGNATION AND SERIAL NO. 7. 1F INDIAN, ALLOTTEE OR TRIBE NAME Doyen, Limited 8. UNIT FARM OR LEASE NAME Doyen, Limited 9. WELL NO. #3 10. FIELD AND POOL, OR WILDCAT Wildcat 11.SEC., T., R., M., (BOTTOM HOLE OBJECTIVE) Sec. 20 T23N R28E F.M. 13.' DISTANCE IN MILES AND DIRECTION FROM NEAREST TOWN OR POST OFFICE* 12. 56 miles ENE Chalkyitsik, Alaska 14. BONDINFORMATION: $100,000 Blanket Drilling Bond - Insurance Co. of North America TYPE Surety and/or No. Amount 15. DISTANCE FROM PROPOSED * LOCATION TO NEAREST i~ROPERTY OR LEASE LINE, FT. (Also to nearest drig, unit, if any) 18. DISTANCE FROM PROPOSED LOCATION TO NEAREST WELL DRILLING, COMPLETED, OR APPLIED FOR, FT. None in 21. ELEVATIONS (Show whether DF, RT, CR, etc.) 1794' surface 1360' area 16. No. OF ACRES IN LEASE 11,520 19. PROPOSED DEPTH 12,000' NO,ACRES ASSIGNED TO THIS WELL 160 20. ROTARY OR CABLE TOOLS Rotary 22. APPROX. DATE WORK WILL START 23. PROPOSED CASING AND CEMENTING PROGRAM SIZE OF HOLE SIZE OF CASING WEIGHT PER FOOT GRADE SETTING DEPTH Quantity of cement 36" 30" 300 1140 PE 18' Perma fr~q ~_ 27½" 20" 94 ]~55BTC 160 ' 560 17~" 13 3/8" 72 ~SOg~c 250~' PpRn **See attached. (86 sx.) SM. IN ABOVE SPACE DESCRIBE PROPOSED PROGRAM: If proposal is to deepen give data on present productive zone and proposed new productive zone. If prOposal is to drill or deepen directionally, give pertinent data on subs'urface locations and measured and true vertical depths. Give blowout preventer progxam. 24. I hereby certify that t_he Foregoing is True and ~.r/~ct (~s space for Stat~ office use) SAMPLES AND CORE CroPS ~QUI~D [ MUD LOG ~s ~ NO [ ~s DIRE~IONAL SURLY REQUIRED DATE May 17, 1977 ~TLE Project Manager [] YES ~] NO CONDITIONS OF APPROVAL, IF ANY: OTHER REQUIREMENTS: [] NO A.P.I. NUMERICAL CODE 50-043-20002 PERMIT NO. APPOVED BY 77-27 APPROVAL DATE ~,~.- ~- TITLE. *See Instruction On Reverse Side May 31, 1977 DATE May 31, 1977 ClJklXP BX-160 13 s/a"-5o00~ DRILLING SPOOL KILL LINE DRI I I I N ¢= SPt'DOt '-~ i '-. I3 5/S"x5000¢ FLANGE (Or AIfe Connection Specified By Operotor I. time Rig i~ ordered.' Any oddtt~on¢t t Spools will be provlded by } or Controztor at cost o~ ~erofor.) CLAMP BX--160 ,,_5000'~ . i"CItOKE I.INE 'CLAMP BX-160 DOYAN ~ 3 THE LOUISIANA LAND AND EXPLORATION DOYAN ~3 COMPANY Blow Out Prevention BOPS NUMBER SIZE SERIES TEST PRESSURE COnductor Surface Below Surface Below Intermediate Below Protective Completion None None 1-Shaffer Spherical 3-Shaffer Ram Type 1-Shaffer Spherical 3-QRC 1-Hydril 3-QRC 1-Hydril 20" 13 10" 10" 6OO 1,500 1,500 1,500 2,000% 5,000% 5,ooo 5,000~ See attached detail on BOP stacks. Ct?NFtDENTI &L' · LEASE AND ',','ELL NO .... Doyon,_ Ltd.. #.3 F;ELD f Wildcat' STATE _ Al aska DISTRICT DIVISION PROPOSED TD CASING DESIGN .SHEET Alaska . 12...,000' T.D. DATE FORM PREPARED PREPARED BY November 21,.1976 GH D-SIGN CONDITIONS EL.=;, :NT.L;:,ER,PROD. 9-5/8 _,_8_5_70 9.6 DESIG[~ CONDITIONS #1 #2 #3 #4 9-5/8 _ 53.5 MN-80 MN- 80 _.. v~.-. ,.,,: :/c=L. Butt Butt ,.,.- :==-.-:,.r. PS,/FT .545 0.472 5,T S'.Z~ v;., ,',*,T:CiF,t, TED SUAF,PRESS PSi '.,.N TE.',S.ON S F. CC' L~=SE,S.F. 0.4994 ' 1.25 686 I 125 th) 1.00 No 8.500 drlg. w..9.6 .@' 12,000' ~ zone has .~'.',. ~'..~s? s F. (1.8 on jt stren 5 SY~NiY SFr:;" "?:FT D:A"ET~-R IN. CLEARANCE c:,~.: TC CS: '.~O,~C I,'~. I I' t CPLG TO HOLE, I.N. [ I s,: :o cs:.~N i 0 - S?e!cial Drift S:LC JC.:NT STr, E¢;ST~ ": h'i:4.Y~ELD: CRiTICaL SEC AREA jO;NT, t,q.z X MIN. Y~ELD, PS; LE~;,,.2 T H 1500 1500 1200 CASI''1 W , ,,g DESiG, . FROM-TO i SiZE ~ WT./FT. ,9-5/81 53.5 9-5/8; 47 9-5/8' 47 9-5/8~ 53.5 O.~AOE MN- 80 MN-80 N-SO TYPE OF JOINT Butt Butt 8 rd. LT&C N-80 ! Butt 437,200.="/i5.547 ini2 = 28,i21~,psi 356,900#/13.572 ini2 286,450#/11. 434 ini2, C~S:~G S:ZE GO, IN ,, , CnSI;,G WE:G?iT =/FT. T Y.r"~' CASING N','$LL THICKNESS , IN. ' 0 CA$;N3 ~D , IN. 8 CASING DP:FT ~N. 8 C~LO., O3. ~',. 10 PLAIN END ~REA , N2 CR~T$SAL SECT',S~; AREA JOINT,IN~ ............ M~N Y',[LD ST;',~,OTH PSI MAX. YIELD ST;-:Er, GT~t ,PSI M;"q ULT TEhS.' E STRENGTH, PiP~ BODY STR~NOTH , JD:NT STR~U.ST~i ~J;N. ~LD, JOSNT $T~Er, STHAPl ,: 1., 329 CC~L=*S~ .*Adj CDr Axial TensNon 5 5~XST, : 80% Min Yield ii j~::~T SFFBurst API _iLL_o- 15oo #2) 1500-3000 f/3). 3000-4200 #41 4200-8500 ·535 8.681 · 379 8. 525 .625 10.625 15.547 4300 80,000 110,000 ~t) Axial Tensil~ Stress 100,000 1,244,000 ,000 £ollap~ (z/,/n axial t~nsinn/ 6,62(1 ,,, oRVAL ;';T. %o ,250 70,500 13.572 56,400 437,20,3 356,950 285,~30 230,050 230,050 1,z61¢oo 3,773 __9~./8__ 53.5 N-80 8 rd LT&C Butt O.472. 0._54F __8 53_5 ...... 8.6_8_1 _ 8.525 8. 379 10.625 10,625 - . 11.434 - 8o, ooo 80, ooo ....... ~..8_o.,__%o__o ..... 110,000 110,000 [!1.0, 0 O0 100,000 100,000 }100 ,_000 1,086,000 __ 1,0_86,000__!!,.2_4_'4=0_0_0_ - 91_5_,000 i - 3,830 i 5 6,.300 6 ,_3_0_0_ _ i L_~_ :f' 6.,~..8..7.0 . 6,870 . ' . ._7=.~30 · .. 4,75fl z~, 75Q ! 7, !00__ ......... I .. 7~930 ' C b .',' ~,~ '¢,' T. SF T£NS;O'; 2. 845 3.042 , 3.!59 ' 5.407 I S F 'r£, 3;'3', 6.873 2.770 1.929 1.560 4. 374 2.!2! "- = 26,297! psi = 25,0521 psi Alaska State Caic. Burst S.F. If ~rld. to 12,(~00' & A BHPI '1.235 Or b.5 psi/ft. ,~_rad. is encJun'tered #3 ! '1.205' t ' o I .__Amd:_the._d.~_g_=~di~] mvn ............... ~ ......... THE LOUISIANA LAND AND EXPLORATION COMPANY DOYAN ~ 3 Blow Out Prevention BOPS NUMBER SIZE SERIES TEST PRESSURE Conductor Surface Below Surface Below Intermediate Below Protective Completion None None 1-Shaffer Spherical 3-Shaffer Ram Type 1-Shaffer Spherical 3-QRC 1-Hydril 3-QRC 1-Hydril 20" 10" 10" 5/8" 600 1,500 1,500 1,500 2,000~ 5,000# 5,ooo 5,,000~ See attached detail on BOP stacks. ~ve: BOND Know All Men BY These Presents, LOUISIANA LAND & EXPLORATION CO. of the County of: ~T~,ird Judicial District as Principal, and I~tSURANCE COMPA1Ff OF NORT~ AHERICA in the Alaska State of: of Philadelphia, Pennsylvania as surety, authorized to do business in this State, are held and firmly bound unto the State in the penal sum as indicated, lawful money of the United States, for which payment, %veil and truly to be made, we bind ourselves, and each of us, and each of our heirs, executors, administrators or successors, and assi~ms jointly and severally, firmly by these presents. The condition of this obligation is that whereas the above bounden principal proposes to drill a well or wells for oil, gas, or stratigraphlc pur- poses in and upon the following described land situated within the State, to wit: BLANKET BOND FOR ALL WELLS DRILLED · -(l~Iay be used as blanket bond or for single well) IN TNE: STATE OF ALASKA NOW, THEREFORE, if the above bounden principal shall' comply with all of the provisions of the laws of this State and the rules, regulations and orders of the Conservation Commission of the State, especially with reference to the proper plugging of said well or wells, and fLling with the Oil and Gas Conservation Commission of this State all notices and records required by said Commission, in tile event said well or wells do not produce oil or gas in commercial quantities, or cease to produce oil or gas in commercial quantities, then this obligation is void; otherwise, the same shah be and remain in full force and effect. Penal sum of ('IY)TAL LIMITS OF LIABILITY FOR ALL WELLS AND NOT PER WELL) ..... $100,000o00 .... (ONE HUMPED THOUSAND DOLI2~P,S At~ NO CENTS)' Witness our hands and seals, this 13th _day of. January, 1977 INSb~/qCE COMPANY OF NOR'IR AMERICA' Principal 13th January, 1977 Witness our hands.and seals, this_ , day of f ~, , ,! Joh Attorney-in- ack' Suret?[ .. ~ (~ the pr~cipal is a corporation, [he bond shoed be executed by ~ts duly authorized officers, wlih. the seal of the ~orporati~ afl.ed.'" When prmc~pa~ or sure~y executes this bond by agent, power o~ at[orney or other evidence o~ authority must accompany the bo~%) / A~S~ OIL ~D GAS' CONSERVATION CO~SSI'ON ApDroved____~. Date CONFIDENTi",I Executive Secretary -- - -----~r.~, Alaska Oil and Gas Conservation Commission Bond Form No. Authorized by Order No. I ~ffective October 1, 1958 17 20 20 2~ 1560' T 23N, R 28E, FAi PROTBACTED SECTION 20 :~BANKS MERIDIAN 17' 20 20 29 16 21 f' = 1000' NOTES i. Location of well site was accomplished ~ using U.S. G eoiocjicol SurveyTriQnguiatioh Stations MEG and FORT. Elevation of proposed well site 1794 feet by vertical angle from b MEG Elevation to :1= one meter accuracy. State Plane Coordinates Zone 2 y a~ 680429.11 x 540 808.13 Public l~nd. Description 2~96' South ~ 1360' EQsI from 21_ the NWcorner of Section 28 T ~.:SN, R28E, Fairl~nks Merldl~l. CERTIFICATE OF SURVEYOR I hereby certify that ! am proper~ registered and licensed to practice land surveyin9 in the State of Alaska end thC thi~ plat represents a i~ation s~v~ ~de by me or und~ my direct sup~ision and that'ell dimensions a~ detaJJs are correct. ~~. DAf E 5 UR V E fOR ' CO FIEiENTIAL. Geodetic Position Lat. 66° 48' 17.72" Long. 141 o 4:~' 01154" LOCATiON CHANGE FEB. 12~I97~,JMARCH4z1977 J GD .... , , REV,ISION ..... DRA,,WlN? , .BY :- LOCATION SURVEY FOR PROPOSED WELL LOCATION DOYON 3 Locoteel in Protracted Secfior120, T2~N,R2:8 ErF'..M,,AL:A ~KA SURVEYED FOR LOUISIANA. LAND ~ EXPLORATION CO. '" $'U/~/EyED BY ' ~' .......... INTERNATIONAL TECHNOLOGY LIMITED ANCHORAGE ALASKA FAIRBANKS BOND Know All Men By These Presents, LOUISIANA LAND & EXPLORATION CO. of the in the county of: ...-"' '"~.~ra Judicial District state && as Principal, and 'INSURANCE COMPANY OF NORTH AMERICA' Alaska Philadelphia, Pennsylvania ~. as surety, authorized to do business in this State, are held and firmly bound unto the State in the penal .sum as indicated, lawful money of the United States, for ~vhich payment, well and truly to be made, we bind Ourselves, and each of us, and each of our heirs, executors, administrators or successors, and assigns jointly and severally, firmly by these presents. The condition of this obligation is that whereas the above bounden principal proposes to drill a well or ~vells for oil, gas, or stratigraphic pur- poses in and upon the following described land situated within the State, to wit: BLANKET BOND FOR ALL. WELLS DRILLED · ~ (May be used as blanket bond or for single well) IN TIlE ~.STATE~ OF ALAS:V~ · NOW, THEREFORE, if the above bounden principal shall comply with all of the provisions of the la%vs of this State and the rules, regulations and orders of the Conservation Commission of the State, especially with reference to the proper plugging of said ~vell or wells, and filing %vith the Oil and Gas Conservation Commission of-this State all notices and records required, by said Commission, in the event said well or wells do not produce oil or gas in commercial quantities, or cease 'to produce oil or gas in commercial quantities, then this obligation is void; otherwise, the same shall be and remain in full force and effect. Penal sum of (TOTAL LIMITS OF LL&BILITY FOR ALL WELLS AND NOT PER WELL) ..... $100,000.00 .... (Ohrg ItI~DRED THOUSAND DOLLARS AND NO CENTS)' Witness our hands and seals, this 13th. day of. January, 1977 INSUF~.NCE COMPA~.~' OF NOR'IR ,~IERICA Principal 13th January, 1977 ~Vih~ess our hands and seals, this ...... day of. /.) 7-~ .iV / //I//./-z" /_ Job Attorney-iht,fact' (If the pr~cipal is a co~oration, the bond shoed be executed by its duly author:zed ofhcers, w~th the seal of the co}potation affixed:' When principal or surety executes this ,bond by agent, Dower of attorney or other evidence of authority must accompany the bond.) / A~S~ OIL AND GAS CONSERVATION CON~ISSION Approved Date CONFIDENTIAL Executive Secretary - _ - .: ,.~,..,.,~, ..... . -- - Alaska OH and Gas Conservation Commission Bond Form No. Authorized by Order No. Effective October 1, 1958 POPOVER ATTOI flEY INSURANCE COMPANY OF NORTH AMERICA PHILADELPHIA, PA. notu all men pre ent : That the INSURANCE COMPANY OF NORTH AMERICA, a corporation of the Commonwealth of Pennsylvania, having its principal office in the City of Philadelphia, Pennsylvania, pursuant to the following Resolution, which was adopted by the Board of Directors of the said Company on June 9, 1953, to wit: "RESOLVED, pursuant to Articles 3.6 and 5.1 of the By-Laws, that the following Rules shall govern the execution for the Company of bonds, undertakings, recognizances, contracts and other writings in the nature thereof: (1) "Such writings shall be signed by the President, a Vice President, an Assistant Vice President, a Resident Vice President or an Attorney-in-Fact. (2) "Unless signed by an Attorney-in-Fact, such writings shall have the seal of the Company affixed thereto, duly attested by the Secretary, an Assistant Secretary or a Resident AsMstant Secretary. When such writings are signed by an Attorney-in-Fact, he shall either affix an impression of the Company's seal or use some other generally accepted method of indicating use of. a seal (as by writing the word "Seal" or the letters "I~S." after his signature) (3) "Resident Vice Presidents,' Resident Assistant Secretaries and Attorneys-in-Fact may be appointed by the President or any Vice President, with such limits on their authority to bind the Company as the appointing officer may see fit to impose. (4) "Such Resident Officers and Attorneys-in-Fact shall have authority to act as aforesaid, whether or not the President, the Secretary, or both, be absent or incapacitated; and shall also have authority to certify or verify copies of this Re. solu- tion, the By-Laws of the Company, and any affidavit or record of the 'Company necessary to the discharge of their duties. (5) "Any such writing executed in accordance with these Rules shall be as binding upon ~he Company in any case as though signed by the President and attested by the Secretary." does hereby nominate, constitute and appoint JOHN R, JOHNSTON, of the City of Anchorage, State of Alaska its true and lawful agent and attorney -in-fact, to make, execute, seal and deliver for and on its behalf, and as its act and deed any and all bonds and undertakings UNL~MZTED in amount, on behalf of Fischbach & Moore, Znc,, its Divisions and designated subsidiaries. The aforesaid bonds and undertakings to be signed for the Company and the Seal of the Company attached thereto by the said John Re Johnston,.~.kAividually. And the execution of such bonds or undertakings in pursuance of these presents, shall be as binding upon said Company, as fully and amply, to all intents and purposes, as if they had been duly executed and acknowledged by the regularly elected officers of the Company at its office in Philadelphia, Commonwealth of Pennsylvania, in their own proper persons. IN WITNESS WHEREOF, the said ................... ..C..~.....D..A...N..!..E..L....~.E.. ................................ , Vice-President, has hereunto subscribed his name and affixed the corporate seal of the said INSURANCE COMPANY OF NORTH AMERICA this ............. , ..... 19.tk ............ 'day of ....... l~o.v, emhe~:. ................. 19..Z5.. INSURANCE COMPANY OF NORTH AMERICA (SEAL) by ......................... .(k~...D&I~YE;~..D~ ........................................... Vice-President. STATE OF PENNSYLVANIA ) COUNTY OF PHILADELPHIA~ ss. On this .................... 1.9.i2~ ........................ day of ............. N.o.v.e:~I~.ex ................... , A. D. 19.~.5...., before the subscriber, a Notary Public of the Commonwealth of Pennsylvania, in and for the County of Philadelphia, duly commissioned and qualified, came ................................................................................. C ..... DAN~EL...I~RAKE .............................................. , Vice-Presid~at of the INSURANCE COMPANY OF NORTH AMERICA to me personally known to be the individual and officer described in, and who executed the preceding instrument, and he acknowledged the execution of the same, and, being by me duly sworn, deposeth and saith, that he is the officer of the Company aforesaid, and that the seal affixed to' the preceding instrument is the corporate seal of said Company, and the said corporate seal and his signature as officer ~vere duly affixed and subscribed to the said instru- ment by the authority and direction of the said corporation, and that Resolution, adopted by the Board of Directors of said Company, referred to in the preceding instrument, is now in force. IN TESTIMONY WHEREOF, I have hereunto set my hand and affixed my official seal at the City of Philadelphia, the day and year first above ~vritten. MAUREEN SCHELL ................................................................................. ......... /~._.~Wd~A~siStant Secretary of INSURANCE COMPANY OF NORTII AMERICA, do hereby certify ~at t~ta~~~5~F~kTTORNlq. IY, of which the foregoing is a full, true and cor]ect copy, is in full force and effect. I~havehereunto subscribext my name as Assistant Secre&~¥, a .~ixed the corporate seal of 3th day of d anuary ........ CONFIDENTIAL CHECK LIST FOR NEW WELL PERMITS Company ,/~X~ ~ Yes No Remarks 1 Is the permit fee attached ~-~- 2. Is well to be located in a defined pool .............. 3. Is a registered survey plat attached ................ ~:~!' 4. Is well located proper distance from property line . .. ....... 5. Is well located pFoper distance from other wells .......... >~i=:~) 6. Is sufficient undedicated acreage available in this pool ........ ~-;,=~ 7. Is well to be deviated ...................... ~s operator the only affected party ................. ~ 9. Can permit be approved before ten-day wait ............. ~i~ ~ tO. Does operator have a bond in force ................. <,~,,,' Il. Is a conservation order needed ................... 12. is administrative approval needed ................. 13. Is conductor string provided .................... 14. Is enough cement used to circulate on conductor and surface .... 15. Will cement tie in surface and intermediate or production strings ~.~ill cement cover all known productive horizons .......... 17. Will surface casing protect fresh water zones ........... 18. Will all casing give adequate safety in collapse, tension & burst 19. Does BOPE have sufficient pressure rating - Test to ,~07 psig 20. Has DMEM approved Plan of Operation ................ Engineering' HHH . JCM~l~i d~', LCS RAD ~ Revised 11/17/76 Well History File APPENDIX Information of detailed nature that is not particularly germane to the Well Permitting Process but is part of the history file. To improve the readability of the Well History file and to simplify finding information, information, of this nature is accumulated at the end of the file under APPENDIX.' ,, No special'effort has been made to chronologically organize this category of information. .o Unconventional air drilling reduces well costs lO-second summary Coring operations or the use of a downhole motor while drilling with air or air-mist are not considered conventional drilling techniques. But one operator .recently performed both operations during an exploratory drilling program and saved money. Problems were encountered, but sav- ings due to increased penetration rates, resulted from being able to drill more footage with air. AIR DRILLING iS used in some areas because of the improved penetration rate when compared to conventional mud drilling. When used with convell- tional logging techniques, air drilling improves evaluation of both explora- tory and development wells. Its appli- cation in coring and directional drilling is li~lited since both are. no.rrnally completed with mud in the hole. But in two recent exploratory drill- ing l)rograms, Shell Oil Co. success- fully comple.ted tile following: · Air cored the objective forma- tions · Operated a downhole motor witl~ air and air-mist to sidetrack a well and to make directional correc- tions. These operations were l)crfor~mcl with air rather tbat~ mt~d to take advantage of an estimated three to fourfold improvement in penetration rate and to better evaltmte any gas shows which may occur while drilling remaining footage to TI). Inclivid~al air drilling operations are more ext/en- sire than comparable operations using fluid, but over-all economics of air drilling j~stify its t~se. AIR CORING Dr5, air and air-mist was used in six Apl~alac}fian basin exploratory wells to core linmstone at dei~ths of 3,000 to 7,700 feet. The cored interval, which varied from 12 to 135 feet in each well, depencled on 'limestone formation thi(-km,ss, reservoir rock (l~ality en- countcrc(l in t}~e first core, and rock I)roductivity characteristics. Since all wells in the air and air- mist coring operations wen, eXl)lora- tory, decisions to air core were strictly dependent on t}~e safety of the operation and on hole conditions at core point. Itl initial wells, about 12 feet of the objective formation were drilled to th. ter~ine if formation gas was present prior to picking up the coring assembly. If gas flow was de- TABLE l~Performance of air and air-mist coring Int~,rv'al (]ored / IN, n(,( rat IonIlll Rotary ltl t ( :o r e(I R ecow,r odlilt ( e Wel I! h t hl)(,{,(l FI u J(I Woll No. i,'~,t,I I,'t.t,I/l,'~'(,t i,'(,ol I)~'r Ilour lh}unds rpm tlm.d l~(}rnll~llot~ l)encrlpth)n ~ . A ................... 1 ,t376-,t395 19/t9 8.-1 I1).0()0 2.q air l,imrstmw ;tnd inte~bechled ~l~;~le · 1395-,1398 3/ ] 0.7 10,000 28 mist Rhal*~ and sandstone '2 ,I;E)S.,139[) 1 / 0 ().4 I(),()()() 2,~ mud S;tmlMone ~ ~.,} ................. ,I ~,I0-,1~o,} 19/18 '~ ~ I ,I.()()() air Y B. ,~ ,> ,~r( :12 Shal limestone C .................. 3 65314151~1 ;10/30 6.3 7.000 31) air Shidc and shaly limestone t;5~fi 1 ..1;i;()3 ,J ~/;{8 6/1 5.()()0 31) air ~h:lly liln,.,tone 66(}3-~1i19 16/ .l 6.4 5,000 ,10 air Shaly limcstum, 7197-7202 5/ 5 ,I.0 5,0()0 .10 air Silicim~s limestone 4 7250-7277 27/14 .1.8 5,()1)0 ,11) air l,imestmu' and sillciotm limeqtone ~,,/7 7,,.}, 15/ {; 69't7-6957 10/10 4.0 9.000 'lO mud Shaly limestone, fractured 6957-6967 10/10 5.0 9,000 40 UlU(] Shaly limestone, fractured 69fi7-6997 30/28 (i.O 3,000 ;l() Illtl(] SJiaJy [imestono. fractured 6997-7011 1.1/1,1 2.9 30.00() 30 mud Sh:dy lira,stone, frm-tured E .................. fi 7738-7750 12/12 1.8 15,0()0 .10 air Niljcitms limestone, limestone and chert F .................. 7 3()51-3081 :10/30 5.0 16,000 30 mist Shaly limestone TABLE 2mDync~drill operating da~ Dynadrill l;oola~e IN'net ration ~urface ()petal Size gl rcu la I lng 1 n I erval I)rl Ileal Ra I e Pressu re a nd Vol u Inches I;luld Feet Feel Feel per llour psi nl cfn~ Inches (~ondlllon I'ounds ................ Air-mist 5.11:1-~.177 6.1 21 '2-11) - 1 '.'()() 7~k mJlh'u~ler '1 ,I-BS-I '200() ................ Aiz-mi~t 5177-5C).~,~ 1(),~ 27 2.11) ................ Air. mist 5779-5~2~ 49 Ii) 2.10 -12~)(1 .............. Air 509S-5144 46 13 Not lei)Id.- I~(}t) I)~ nliJlcuitcr '1'2-1{2-[ 3()00 .............. Air-mist Su~ fa('e test ..... 15()- 12()() ......................... .............. Air-misL Surface tesL ..... 200- I ~(~) ........................ .,, tectcd~cither prior to or during air coring--the well was to }m loaded with mud and coring resulnCd. A~a 8 5/8-inch surface casing string of sufficient weight and grade capable of withstanding maximum surface shut-in pressure without fracturing the formation below the casing shoe was set. Su.rface casing design was based on'normal design criteria for drilling exploratory wells and' 'provided nec- essary safety precautions for air coring. Typical coring assclnbly itach~ctcd 6 23/32-inch x 3 1/2-inch diamond corchead, standard 5 3/4 x 3 1/2-inch core barrel stabilized near bit 'and every 30 feet, circulating control sub and jars. Normal operating procedure was to cut the first core with a 30- foot barrel. If additional 'coring was warranted and if no problems were encountered on the first run, an ad- ditional 30-foot core barrel was picked up, resulting in 60 feet of cores on successive runs. Typical drilling variables were' · Bit weight, 5,000-30,000 pounds s Air circulating volunm, 1,200 cfm. Table 1 summarizes air and air-mist coring operations and shows data for muct coring in similar formations. The 6 23/32-inch core hole was reamed out to the original 7 7/8-incl~ size. Air and air-mist coring attempts in all six wells were only partially stic- cessful since two wells/'etl~lired loacli~g cvitlc~t. 'l'llus, oi~cratimis were tc, n~li- n a at~l di:,~o~ld core}w:td wear. ja~,ning occ~rred in lliree wells, tllus rerl~irin~ frccltmnt' trips to core re{ii,ired footal.le. Of II,'se Ili~'~'{' we, lis, two were cored with dry air and one was cored with ~nud. In tl~e l'C~laining tl~l'Ce wt:lls cc)red witl~ air or air-n~ist, 1)arr{'l jail~)ling was not eviclc~t corehead wear was a l~roblem in two of the three wells. No definite conclusions were lnnclc rcgarcling barrel milming tendencies of air versus mud coring, due to for- marion variations encountered. Al- though mud cored intervals sl~owcd a more severe t')arrel jamming l)roblem, the fractured nature of thc shaly linmst0ne was probably tlm major cause of the difficulty. There were no indications of fractured formation thc air cored wells. But core break- age was evident along thin interbcct- ded shale planes. Data suggcsts that barrel jamming tendencies witll air and air-mist coring arc prevalent. Only three of eight runs with. a 30- foot barrel successfully cored the tire 30 feet and average footage cored per run was 21 feet. l)iamond corchead wear also was encountered while coring with air air-mist. Maximum footage cored with a single corehead was 93 feet, with an average f~tage of 35 feet per bit. Diamond usage ranged from 38- 70~ of the total diamond carat weight and averaged 48%. Based coring rates and a description of covered cores, most diamond usage al>peared to be duc to a highly abra- sive silicious section encounterccl wliilc cori~g. No major advantages of using versus air could be detected since 111(' S;llll(~ ({tl;irtz S;lll({SlOIl(' sec'ticH~ xvl~h'l~ ~{;~t~;~g('(I Iww, I,its wl~ih' air ('~,r- <'{~n'l~,;~(I life will~ ;~ir, air-~list {,' in si~ilar for~nations. , (:()reel wit}~ ~]~a(l was 979},. Althot~l~ harr('l .]a~nn~i~)~ a]~(I cor('- Iwa(I wear i)r()l)l('~s wen. c()stly, average $14,000 per well was saved i~) tile four wells ('orcd i~sing air or air-)~ist. (losl snvi~lgs wcYe duc to i~tl)r()vccl iw~mtrathm I';Ite wit}x air I)clow tim cored interval. DOWNHOLE MOTOR l)ry ;iii' anti air-niis{ ()l)('rated l)yna- drill rt~lS were succ:cssft~lly co~nt>lcted in two ('xl)loratory wi'lis. ()l)crating lwrf()r~nanc'e c)f tim (lifl'(,rcist tools used is su~n]nariz('d in 'l'able 2. 'Die first---a l/lack Warrior basin well--was air (l,rill('cl to 10,200 feet hcfor(' ('~)cott]ltering a ~liajor fishing job. Following t~nsti(:cessfq~l att(,mpts to recover tim fis}~, tim well was 1)lt~gccl back to 5,100 feet and side- tracked in a i)cnnsylvania~l shale sec- tion using a 9 7/8-inch nfillcutter bit on a 6 l/2-inch Dynaclrill. Uater, hole was reamed to the original size of 12 1/4-inch. 'l'he cl()wnlmle motor was ol)erated with dry air for a total of 3 1/2 hours and ]lladc 46 feet of ~ew hole. A ]~lixture c)f oil a,d graphite was in- j('cted into tim ctry air stream at rate o~ I l)ound i)er ]ninute with a chemical puml)in an attempt to pro- vide nec('ssary lubrication. The oil- ~ral)hit(~ lul)ricant was t~sr'cl of rec()~nm('nctecl (lry gral)liite because a s~itable graphite injector was not available. An Al)palacl~ian basin well was air- ]~)isl (]rilling when it ])('C;lllle n(~cossal'y Ir) clrol) hole ;~n.~]e and/or cl~ang(' drift (lirection to l~it a spt, tiffed target. Initial atte~)l)lS to sufficiently clrop l~o}e a~)gle })v r('cl~('ing l)it weigl)t and xviI[~ ;~il-Itlisl w;~S ll~;('l] I() IIIl'll tile }l()llr I¢)1;I] li(l~;~l, w;~s c()l)si(h'r('cl satis- ('(wr('clio~. l{('('nt~s(' of a s}~ort ~)criods, 3 ti)4 l~()urs~ t}m~ ])ullcd aLd the bit changed. The 5-incl)..? r operated satisfactorily, drilli '1 feet of new hole in 9~ hours. initial a~d two s~cccssix'e r~,~s. Nor- nmlly, this olwrati{m would take 1 to 2 hours, lint witl~ tl~e ~mtm' on bot- ated intermittently. Downl~ole motors operated success- h~ll7 :t~,l ch,.sircd rvst~lts w(,r{,. i~ Imt}~ wells, l lowt'ver, tile. 6~-i~{'1~ motor, operatecl with dry air and oil- graphite mixture for lubrication, sus- taim'd clamage--rttl)l>cr mom-r stator assembly required rel)lacv~lent. (iause of this damage, though undetermined, may have been due to frictional heat- lng or excessive opcratin~ slmed when running tim motor off bottom. No damage was detected in either the 5-inch or 6~-inch motors operated with air-mist. Air volume requirements necessary' to operate the downhole motors were witliin compressor and booster com- pressor capacity normally reqt~ired to air drill a well. Both the fi-inch and 6~-inch motdrs were successfully op- erated on bottom, with air Circulating volumes of 1,200 and 2,000 cfm, re- spectively. Air volume meast~red in cfm, is about equal to 5.5 times the recommended liquid circulating rate measured in gpm. TWO different 6~2-inch me, tars did not operate near the bottom even though during surface tests, motors ran satisfactorily. In this case, air circulating volume was 1,200 cfm, which was equivalent to an air to liquid ratio of 3.7 cfm per gpm. The manufacturer's recommended air vol- ume necessary to operate the motor is 4.5 times the reco~mmnctecl liquid cir- culating rate. l)ownhole operation with air and air-mist allowed the drilling of an athlitir)~al 7,50() fct't ()f lmle witl~ air 'l"his article is taken frown j. D. D'Agostirm's l)al)er "Unconventi()nal 'l'ecl~nitl~cs A})i)liecl t() Air l)rilling Operations" presented to tl~e 21st An- nt~al Petrohmn~ SI:crt Course, Texas Technological University, Lubbock, Texas, April 1974, IIIBI,I()(;RAI'ilY I)vna-Drill Ila~dbook, First Edition, Copyrigh~ 1970. ~ Fig. 1--Shown in the operating mode, the Class III Oil Recovery System has water spray booms which herd oil towards filter belt recovery. Oil recovery system operates effectively in rough water An oil skimmer deals with hazards encountered in an oil spill Pixie Gascoigne, News l';clitor, \Vom. n (')Tz. A x'~.:]~s,vr~l.~.: 'rv],].', ()1 ~)il si)ill NIAI(CO l'ollution C, oixtrol (',()ri)., St'attic, Wash. ]'he etluil)m('nt is till ski~]~mr, wl]i('h can ci('ntly ('vc'[~' tlllClt'r I);ltl w(';Itllt't' coil- ctitions. 'l'}xc syst(.m~ was (lev(,l(~l)c(I origi- n;~]lv and tested }~y ~[aI'tin-NIar{etta. MAI{(',() P()lltlti()t)C(~ntt'()l tit(,, iclea anti })ttt it to work. 'l'l~<~ first Class iii Oil Resovery System took eight re(ruths to co~)strx~ct. Each phase was t(.st(,tl as c:On~l)leicd and i~)prove- Operation. In tl~e Ol)erati~L~ llmde, IW() W;~It'I' sl)r;~y I>~)(),~s, att;tcixc(l to tlxc f'rtmt ()f tilt' vcss('l, are cxt('nde(l, ])crtli~Lq oil tt~war~ls lilt('r I)('lts. l{elts ;tr(, l(~wt'rt'd ;tx ;xz~ i~clilw i~to the watt'r it~tl can bc ~xlixtl(~ st;ttionary at any ~)osJli()n (lcsix'txl, l)ual lxydraulic ~t~()t()rs witlx in~l)clhu' i)rol)c, llers draw fl();tti])g (~il and debris ix~to tim filter Juu~ ~v~,4 ~ 93 The pote ': ial o'f stable oam Shell Canada's TOm Mitchell recently discussed tecimiques of stable foam drilling and its limitations at a meeting of the Canadian Association of Drilling Engh~eers. Drilling with stable foam has probably reached close to thc maximum depth for safe opcratiops with a 12V~" hole to 4,640 feet, Tom Mitchell of Shell Canada Ltd. told a meeting of Cana- dian Association of Drilling Engineers in Calgary. Drilling parameters and computer programs had not been invented when he started as a roughneck with Can-Tex 37 years ago, Mitchell noted. There have been no major changes of a revolutionary nature in drilling and a man who started 30 )'ears ago would still find the rig layout familiar, but there have been vast improvements in methods, largely due to hard work. Improvements that used to meet with resistance fronl the old toolpushcr who was proud of drilling to. 10,000 feet in 90 days have made the industry more successful, Mitchell said, and engineers have been a contributing factor. Slarted in fl)olhills Shell's use of stable foam 'in drilling operations to control lost circulation started in the Alberta foothills, after severe problems with two wells in the Limestone Mountain area which lost circulation for periods of 20 to 30 days. When Shell went back on the Wilson Creek 7-22 wildcat in 1964 there was another case of extremely bad lost cir- culation in which almost everything went down thc hole. Materials included truckloads of Shale up to 5" or 6" diameter which just disappeared, asphalt shingles wr, appcd in chicken wire, and 8" x 8" buildirlg blocks which were never seen again. Finally drilling blind with water at this point was successful to the casing point, although it took tremendous volumes of scarce water, so Shell turned to stable foam for subsequent wells. In the Limestone A2-13 well, surface hole was drilled and casing set with no problems. Then foam drilling equip- ment was rigged up and gave full returns to !,300 feet when returns were lost. Up to that point 450 cfm air was used with 10 to 15 gpm of water under .,"-,-, · ~ _, .1. __ 1 1 /'-'7£ pressure up to 680 psi. Drilling con- tinued under the same conditions to about 2,000 feet when pressure started to fluctual.e wildly. Thc pipe got stuck at 2,453 feet and had to be broken off and jarred loose. While this was being done several hundred barrels of mud and lost circulation materials were pumped, and apparently this was beneficial because when tile hole was cleaned it was possible to continue air drilling under fairly normal conditions. No more problcn~s The hole was drilled to the casing point at 3,500 feet with 15 gpm ofwatcr and foam and 450 cfln air at up to 450 psi air pressure. At the casing point 450 barrels of mud wcre pumped in, tile well was logged, another 400 barrels of mud were put in and then casing was run and cemented with no problems. In the Limestone 4-4 well circulation was lost while drilling surface hole at 100 feet, Mitchell said. After a couple of days foam equipment was rigged up on thc conductor pipe and the surface hole was drilled so satisfactorily that surface casing was run in clean hole, with 450 barrels of KCI water. There were no returns to the surface but batch mixed cement was poured down the outside and a good cement job rcsultcd. The hole was blown clean and the cement drilled out with foam. Erratic returns Drilling continued with light weights, with the use of air hamlncr and foam try to keep thc l~olc straight. At 1,500 feet thc hole angle was not critical 35,000 pounds weight was applied thc bit and use of thc air bare,ncr was discontinued. Drilling with fearn con- tinucd to 1,900 fcct where returns lwcame erratic and this continued for the rest of thc hole. l lole conditions were very good while drilling this interval. Frequent surveys indicated up to I00 foci of fill [)tit thc hole cleaned out well and there ,,'as tight hole except for one spot at 3,900 feet where tile drill was stuck for an hour. Thc casing point was reached at 4,650 fcct with no further trouble. After pumping 400 barrels of mud in thc hole was cleaned and logged, casing was set and cemented with no further problems. This hole was the deepest 12~A'' xvt'l' that Air Drilling Services Intcrnationat had cvcr drilled with fearn, Mitchell holed. Total cost was $1,445 per (tax plus $21 per hour for total day rate el 51,900. Density of thc foam was 0.4 t. .().8 and injection rates ranged from to 25 gpm with 15 gpm average in th.' liquid phase and 350 to 900 cfm air thc gaseous phase. The system is very similar to air dri~i ing except for thc foam pump. 'I'hrc~ compressors were used to achieve tit 900 cfm maximuln rate. The generator is thc key to stable Mitchell Cml)hasizcd. Foam goes fro~. this point down thc drillpipe in condition and contamination by tion fluids is minimized. 'l'i~ne c()nsu~ing Thc l]incstonc A2-13-34-11W5 ~.:. n~adc 2,761 Feet in 22 days with while thc 4-4-34-10W5 well made 3,t)t :' fcct in 21 days. Average pcnctratio,: rate xvas 10.9 feet per hour in bet', wells. Surveys xvcrc time consuming. Mitchell explained, but because of thc complexity of thc structures in this arc thc crew had to watch carefully (tcviatio'n. Six bits were used on hole in thc foam section. Mitchcll siad it is advisable lo usc nozzles with foan~. bccilusc whcll thc nozzles were rclllox l}~c pcnclratit,n rate dropped by half about 5 to G I'cct per l'l()ur. Thc lion r;~tc wits Ctlt~ally good with bt~l water was scarce and vcFy cxpcn si VC. ~'hcrc were only minor Freezing' problc~ns with winter drilling, Nlitchcl: said. l.ittlc lime was lost on the first well dive to freezing, and lhcrc was lost time on the second well which dr/fled in an exceptionally mild winter Thc soap 'and water mixture could I,c prevented fl'(~n ['rcczing if necessary insulating thc linc. CARIBBE/ SEA --11° ~ MAR~ TORTUGA o CARACAS BARCELONA % LOS TESTIGOS · MATURIN TRINIDAD GULF © VALLEY AREA + + ~- GUAYAGUAYARE FIELD VENEZUELA TUCUPITA --8° 0¢,~ CUIDAD (~ BOLIVAR MILES 0 20 40 60 80 100 I I I I I I 660. 62° I I Fig. 1. Ouayaguayare riehl, Tril~i(ht(1, W.I. Aerated Foam Drilling In Trinidad by Khem Jokhoo, Texctco Tri.id.d l.c., Triuid. d, W.I. Foam drilling in low pressure partially depleted, unconsolidated sandstone reservoirs in Trinidad began in early 1973 in the Marcelle Valley area of the Guayaguayare field after unsuccessful rotary drilling with conventional mud systems (Fig. 1). Some 20 wells have been successfiflly drille(l an(I c()ml)let(~d using a stable tbam circulating system. Problems of sloughing and lost circulation presented difficulties at t}~(, begin- ni)~ but, I)y a(I.jt~stin~ t.(,('l~ni(p~(,s, l~)a~n Ires b(,(,~ very f~)am, is a fine grained, silW and unconso]idate(l 10(){) l't :u)(I is ~()() t.o I()0() ft, thick. Ifs aw,rages 50 m(l ml(I iL has an average aritl'~mede it,y <,f 1~%. The z()ne has a I)()tt()m hole pressure to 500 psi. I'rior to fi)am drilling, 9 to 9.5 lb/,~'al water has(.,. oil base mu(Is Were use(I as drilling flui(l~ wKh lost circulation l)rob]ems. Drilled solids and los~ circulation material entered the higher permeability intervals re- sulting in low initial l)otential and ultimate recovery. The formation damage as a result of conventional mud systems !ms been confirmed by the excellent initial potential of the new wells which have been drilled with fO;Ill]. The tbllowing e(tuil)me~t ami techni(lues were em- ])loyed by Texa('~)'l'ri~i~l:t~l Inc. to ~lrill wells with l,i~luid flow r:tl,o n~,l, er Calmld~, of m~asuring accu- at varying ratvs :thai w~,'king l,'essures ti'om 125 to 1000 l~si. · Rotat. ing hea(I al,tache(1 b) tl~e wellhea(1. A c(,nsta~t, circulating sub m' back ]wessure valve every 300 t't i~ drill pipe to allow ILr making con- 24 PETROLEUM ENGINEER, JUNE, 1976 ./ Aerated Foam nec(ions without expan(linl4 .,e entire column of stable foam in the drill pipe. · 'A drill pipe float valve installed immediately above the bit to prevent back flow from plugging the bit. · Foam mix blending tanks. · T~p!ex mud pump ~ used for dhlling surface hole pdor to convemion to stable foam system. Stable Foam Stable foam is a mixture offresh water, detergent, appropriate additives for body, and compressed air..It is generated at the surface and injected into the well the circulating fluid at weights as low as 0.27 lb/gal. Various combinations of the foam-mix have been em- ployed in Tdnidad, but the most satisfactory to date hms been a ~xture of fresh water, ~/z to 1% of an anionic foamer, % to Vz lb/bbl of a polyanionic cell~ose compound as ~ additive, and sufficient caustic soda to adjust the pH to 9 to 9.5. The higher concentrations of the foamer ~d additive will result in a more. s~ble foam, but the lower concen~ations may be employed under some conditions'rest(lng in a considerable sav- ~ in mateh~ cost. Stable foam has the inherent ability to neutralize noxious acidic gases such as hydrogen sulphide be- cause excess a~aH metal b~e matehals ~e cOnta~ed in the foam ~. Fu~hemore, if the gases ~e not completely neutralized, they are trapped in the stable foam. ~ese prope~ies of the stable foam could prove to be beneficial from a s~ety standpoint if the foam were uti~zed in a hydrogen s~phide producing ~ea. Drilling Techniques In the Marce~e Valley field, a 12%-~. hole d~lled to the top of the pay zone with conventional mud and ff%-in, casing set and cemented. An 8Vzdn. hole w~ then drilled into the pay zone using foam as the circ~ating fl~d. After reach~g total depth, the well b circulated with foam for two houm p~or to pulling out to log. An induction elect~c log ~ ~n, and then 6%-~. casing run uncemented with a prepeffo- rated section of casing across the productive interval. Since the producing hohzon is not exposed to any extraneous fluid other than the stable foam, no fluid restriction or completion damage occurs. 'l't~e li~lui~l flmm m~It~ti~m is In~mlwd by :t t,ril~l~x lilt'(li:tl('ly tll)td.l't':t[ll ()r (.il(, f'()~tlli ~U,ll(,r.2t(.()l. [)()x, ess(~f~l,i;tJ ~/i;tL :L c()ll6ifitl()tls ('()[Llllill (){' at.al)lc [~);tlll maintained ¢rom ~he s~andpipe ~o ~he blooey line ~o enabl(~ fi)am ~() li¢~ cutLirigs an(l l)r()(lli('(~(l flui(la [rom tim wHit,re'. Tim ;Lr]l~ill;tr VeJ()ci~y whih~ ¢'.ircul;d, ir)K was kCl)L l)eh)w :~()() ft/r~in ~() :m nf)t, t,() (w()(le wellbf)rc. For (d'ftx'.~ive removal ofcuU, inga aL Marc(die Valley, ;t Ininirnum ann~laF velocity o¢ gO0 fi/rain was re(ltl ired. Th(~ t,ype ()f fimrn irkjecti()n pr'()lU';trn in fi)am drilling will vary if the fi)rrn:Ltion is flowing en()ugh water to (lisl)erse cuttings, l'he fi)am is in.jetted cont, inu()usly with the minimum amount of water required for trans- porting the cuttings to surface. I f there is insufficient water to disperse cuttings, a(tditional water is added with foam at the surl'ace. An inerea,se or (tecrease of drill pipe pressure indi- cates a change is necessary in (1) the blending rates of either air or foam, or (2) the percentage of the foamer in the liquid-foam mix or (3) the penetration rate. Table 1 is a driller's kmide as to the remedial action necessary when pressure surges occur. TABLE 1. Guide to Remedial Action. .Pressure Change Pressure Decrease Pressure Increase Probable Reason Remedial Action Normally air break- Increase liquid foam- through and formation mix rate or decrease of unstable foam. air injection rate. Possible sloughing Stop drilling. Pull formation, up drill pipe and restore circulation and work way back to bottom. In Trinidad, the chlorides content of the returns is measured to determine if water bearing sands beneath the pay zone are being drilled prior to reaching pro- jected TD. The base water chlorides are measured befi)re mixing with foam, and this is used as a com- parison test with the chlorides measured in the re- turns. An appreciable incretkse in chlorides indicates the bottom of the pay zone and entry into the water zone. If the water zone has been penetrate(t, it must be plugged off. This is done preferably in open hole after logging, but it can be (tone inside casing after producing the well if high water cuts are obtained. Techniques of utilizing foam while drilling vary from well to well even in the same reservoir. Well conditions dictate procedures, and no set of standard instructions' are applied rigorously. Past experience must be incor- porated and adjustments ~nade where necessary. The most critical aspect of the use of fi)am as experience(l in Trinidad is that the foam must t)e stable thr()ughout the system until it leaves tile bh)oey lin(: where the fluids an(l gases set)arate very r:Lr)i(lly. The Foam is n(,ver rccycl(~(l. A g()()(l injecti<)n [)urnl) is ~mcessary, Several techni(lues ()f runnilig t'asillg were ath)pted Lo overc<)rne the [)r()blenl ()f })()h~ sh)tJghing. T('ch- rli(lUeS inclu(lc(l (1) ru~lnirlg i~r('r)('.rfi)rat('(l casing across t,hc p:ty z~,rw wit,t~ :t the [)()LL()IIl ()1' t,l~e sl.rilu5 (2) rurining unt)crfi)ratc(! casing t() total (lei)ti) with ;~ the b().tL()rn ()f the casinK ami i)crfi)r;tting (h,sire(l intcr- WLIs, (3) (Irilliz~g tim last, I1)1)0 ft ()f }.)h' with the casing an(l peril)rating tile cfi(ire iz~terval without logging 26 PETROLEUM ENGINEER, JUNE, 1976 GAS BRI AK[R WI IH CltlMNEY ~,O1TINGS PI[ B STAN ROTATING HEAD HYDRIL&' !t B. O. P. T-20 RIG TRAILEf Fig. 2. LayoU,t of T-20 rig for and (4) running unperforated after logging with a bit on bottom ~o necessary and perforating the ing of the perforated easing was a wash pipe type paekoff of the pre which allowed full circulation at ti~9 necessary at times'on wells sloughing. The most sueeessfu'l procedure us~ minimize reservoir damage and fluids to the low pressure formatio~ wells to the top of the pay, run and then drill to total depth with COml)letion with preperforated the lmy zone. '~ iml~,n(li~' tr(mlfle. Wll~n the (Ir()l)S a,.I ~ll(, Ii):~:t: (,(,:~s(,s t()lilt cie~t.l.y. IL ti/eh I)(,c(~n('s necessary 28 WATFI{ 'fANK J t. IOUID METER r CIA M GENI'RATOR BOX ' AIFI METER JAIR COMPRESSOR .. C-150 USED AS A ,T~ANSFER PUMP ..,,!....,,,, .~ K-500 USED ON .GUNS AND RIG. .,!:?: ,~4his slug causes tl~e flow to hea(l and $Vhile this is not a regular practice, it s' an(1 mud ring's. ,quate air volume and foam mix are drill soli(ls and fluid entry, the ability of is the only limiting factor in sue, lling in low 1)ressure reservoirs. practice, the hole should be circulated to clear of cuttings betbre making' )nt, inuous circulation while making ~visable and can be accomplished by circulation subs in the drill string, if back l)resstir(.' valves can be in- · ~ . komat~cally in the ~lrill i)il~e. This allows fin' nd wns ns h~w ;is ().~7 li)/K;d. Tills low :(te(l. All ill('l'(';Is(' givos the l'(~:tm H]()~'t~ b()(iy :tn(l, Lhenee, its Visc(),~i(y. A~l i~l('~'t'~s~ iH i~s viscosiLy Cal'ryillg PETROLEUM ENGINEER, JUNE, 1976 Whenever a very heavy stiff mixture is required, a gal](,ll ()f foanler [)el' barrel of water can be tlsed. Also, incr~,asing the i~.jection raU~ increases the cm'ryin,~' cal.)aciW of Lhe fi)am. This low density, high viscosiW foam achieves a very low bottomhole circulaUng l)res- sure which minimizes or eliminates lost circulaUon. The makimum densiW used was 0.6 [o 0.8 lb/gal. Drill Pipe SUcking Drill pipe sticking is nec a problela while drilling. with foam in Trinidad because constant cireulaUon and good quality stable foam is maMtained. ~en'pipe does stick, the most frequent reason is Um hole has riel been cleaned when a Connection is made. The cuttings remaining in the wellbore hll back and wedge around the drill pipe. ConUnuous circulation is almost impera- tive in foam drilling. Rate of Pene~raUon The rate ofpenemttion when using fimna as a drilling fluid is much higher Umn with oil or water or water base mud through the same formaUon because hydro- static head of fluid above [}~e bit is greaUy reduced. Thc penetraUon races are resCricted primarily by the carrying capacity of [he foam. Some opUmum drilling rate must be developed whereby an excess of euCUngs never exists above the drill bit. Various concentrations of liquid foam-mix have been employed us~g different foamers. Foam SysLem I composition was 1% by vOlume of detergent, 12V2 lb~bl Bentonite, 2 lb~bl guar ~m, 1 lb/bbl soda ~h for pH of 9 Co 9.5, and fl'esh water. A pump rate of 0.55 bbl/min and a compressed air rate of 400 eu fi/rain was used.-Foam System II composiUon was 1% by volume of anionic foamer, .iA Co h lb/bbl of a polyanionic cel- lulose compound, caustic soda fi.,' pl.I of 9 Lo 9.5, an(1 fresh water. A pump rate of 0.33 bbl/min and a com- pressed air rate of 200 cu X/mM was used. Table 2 shows a relationship between peneCraUon races and dhlling fluids. using the teml)erature log, be. cause of the cooling feet {d' the gas as it eXl>amls into tl~e lmle. l)ue Lo hole sl~>ughing probit,ms, the initial open fin' h>gging, llole cavin~ problems were lmrsis- tent, however, so the ln'Occdure was changed to sim- ply circulate the hole thoroughly wiU~ fimm. If oil is present in the hole, iC is very difficult to obtain a reasonable S.P. and a short normal curve. The GR/IES were obtained when fi)am was used as the drilling fluid. EconOmic Analysis Comparing costs of foam to mud as drilling fluids is not easy. Figures can be tabulated and comparisons made, but whether it is meaningful when applied to other areas remains to be proved. It was evident, however, that the cost of a fi)am ~Sg is higher than a conventional mud rig on a daily basis. On a job basis, might be cheal>er to {lc'ill a given well wiCh tbam xvith mud because of tl~e increased l>enetration rates achieved and a lesser risk of lost circulation and differ- entially stuck l)il)e. Drilling costs l'r(,n~ t{,1) ()f l~ay h, c(>ml)let, ion of well were 15 to 20% lower fl)v wells (Irille(l wiLh the fi)am system as compare(1 to previous wells with conven- tional mud. Considering only drilling costs m~d exclud- ing all other expenses, foam is more expensive as a drilling fluid than mud. Data collected in drilling tl~e Gros Morne VI sand reveal that drilli~3g fluid costs are U.S. $6/f~ to drill with fi)am compared to U. 8. $4/f~ mud. These costs would need revision in future appli- cations due to inflationary trends in the cost of the basic ingredients of the stable foam system. Acknowledgement. The author ix grat(.ful Lo the staff engim, ers who e(lite(I this paper, t() riehl per.qonnel who assisLod in gaLhering the necessary infl)rmatim~ to make this i)al)er possible, and to Tex- aco Inc. for granting l)ermission to publish this paper, TABLE 2. Penetration Rates and Drilling Fluids. Feet of pay Avg. penetration Drilling No. of wells drilled rate fi/hr Fluid 4 2575 26 Foam System I 1 880 63 Foanl Sysl(m~ II ()l)C'~ 1 l()le kV(!llb()res c()l)t,ai~ling I,)llui(I can ()~)ly with t,<,ds t,lmt, n(~e(I ~() t]~i(1 t.~)(~st.al)lis}) ('m~l,a('l, with t,h(, f(.'mati(m. '1'1~(, in(luctimi log was t'~>u~i(If(,'~mti()n resistiviUes i~l Imles u~,ler stl('J~ Tho Gamma Ray log was used to diaUnguish shales from sands. Tho neutron log was someUmos used to determine gas bearing zones where a gas-oil conLac[ was'suspqc[ed. These gas zones can also be detected 32 About, the Author !lr.d/.th'd i. 1971 (',,tttht. tt,il/t . linc /, Id/,q,,i~':*, Ih',h,i,~'~t ,Ih'hi In'lr~dt'/t./ h(t,q m'rm'd h/ lite ,rich{ C.flim,cr ..d Ic/t./ C.flim'cr, Ih' htchrd Iv It/c /'~,~;~,,'t,~i~' ,~'h~[f rc,~'crvoh' c.gi.cer. PETROLEUM ENGINEER, JUNE, 1976 NAL[~O MULTIPURPOSE FOAMING AGENT FOR USE IN AIR DRILLING AND HYDRAULIC FRACTURING Composition Anionic Surfactant Anionic Surfactant pH 8.3 7.8 Density 8.3 8.3 Color Light Amber Light Amber Pour Point -5° F -20° F Flash Point (TOC) 130° F 87° F . Toxicity Non irritaling from' Non irritating from external contact external contact ADOFOAM & ADOFOAM III'r-l, liquid mix- tures of anionic surfacc-aclivc agcnls, produce maximtm~ stable foam under fieht conditions. In air- and mist-drilling opera- tions tlney prevent bailing tip of mud and cttttings, and aid in their removal. In hydraulic and well cloan-otH, tho st~porior st~rfactant prop- crtics of /XI)OFO,,XNI & ,,XI)OI:O.,XNI l/I':-I a~- sure efficient removal of water, condcnsatcs, and sludge. Since con~ing on ll~e m:lrkct has proved lo be ;t s~pcrior l'Oillllillg ;tl~elll fei' fresh and brackish waler systems. Time and time again it has proved more economical than ils colllpelilol-s title Io ]oweF list co~lCClltl'itlio~ls. 10(~7, AI)()I.'()AKI IIl:..l wi~s i~trodt~ced Io cope trcmcly hard walcr. It luts I)cc~ Iho~t)t~gl)ly fichl- tested in ~he mosl rii,.orot~s con,Ii,ions, which inclt~d(: hiId~ oil c~('c~lr;~lion~;, l:(u' frcsl~ ,~se AI)()I:()A[I: Iro~ Ille'rc I(~ s;~lt~raled bri~c use AI)Oi.'()AM IIl:-I for lng efficiency for air-drilling, wnler fracturing, acid fracturing, and other clenn-ot]l problems. ]loth l)rodticls ;lis() reatlily h'ml II}enlsclvcs usc in "stiff-foam" :il/ti "mud-misting" :ll~Plica- tions, The first acttml oil field usc of "stiff-foam" in foam clean-out work was wilh ADOFOAM. used AI)OFO,'\~'~I & AI)OFO/\NI BI:-I' (I) }II",NNI:SSI:.Y. ()KI.AII()MA. \Veil deCl-,Cm..d in Me[';~nac formation from to (~7{)i)'. (h'u{Ic oil ami form;ilion b,'i~lc were flowing into thc Ixdc .al all ul~dctel'- mined rate. t.'luid injection was 8 bbls./lar. of fresh water containing 2 gals./8 bbls. of ADOFOAM: fluid recycled from pit; size of hole 4.'.; ". AI)OFOAM was used inter- miltontly with a compotitivc foamc~ com- bination whoso total cost per concentration used was in excess of A I)OFOAM. Average hole pressure using AD()I:OAM was 50(/ 550 psig: average pressure with other foam- CF was 6()() to 6q(). psi,,. ~. When unloadin~ hole after a connedion, AI)OFOAM loaded hole in a sic:My flow of 90(I psig while competitive foamer unloaded in largo spasmodic gushes at 11()0 psig. (2) DENVER CITY, TEXAS, Well deepened from 6200' to Clcarfork to 7250' in thc Wichita Albany Wasson field. Hole was~making large x'olumc of oil from the 6200' zone, but little water. Injection for mist-drilling consisted of 10 bbls./hr, water with corrosion inhil~itor and 4 gals./10 bbls. foltmCl', l,inc presst~ro wits 5()(} Io 550 psig. AI)()I::OAM st~bslilutcd at 4 gals./10 bbls. water decreased pressure to 420 psig. anti increased cutting returns. ADOFOAM con- stittiled less cost at usc-concentration than the other foamer. Drilling rate improved to an average of 13' to 14' per hour. (3) A1Ci'I:,SIA, NI:,W MI:.XICO. Opera- lots had tried tlnsuccessfully numerous limes to foam drill through a salt Section from 24(1(Y lo 2$50' with foamer concentra- tions as high as 8 gals./8 bbls. water. Pres- sure would risc from 3f)O psig to 56() psig ',lnd circtllalioll xVotlltl cclisc. Mtld was lhc~l the o'nlv solution. Operator used Al)O- FOAM B}:-I soon after inlrodudion wilh excellent results. AI)OI:()AM BF-I concen- lion was 3 gals.'S bhls. of w;tlcr. Pres- Stll'C IleX'Cl' exceeded 3{fl) psig and l'cltll'lls Iv s:tll-sa uralcd 'after first 50' in tho sail St?CI iOI1, LIME WATER CONfAINING 5% NaCI AND CRUDE OIL (Concentation needed to foam out 800 mi fluid/10 rain) QUARTS PER 8 BBLS. H:,O ADOFOAM 4.0 9.2 A 5.4 14.8 B 6.3 24.4 C 8.6 29.6 D 7.1 21.6 · E 12.2 18.0 SAIURAI£D BRINE & 2,5% CRUDE ADOFOAM BF-1 6.1 F 11.0 O 16.2 I/iodcgradal~ilily, dccomposilion aim dcslrt~clion by. b;tcleria is axst~l~ing :ll~ iml~orlant role in ~n;tnv gcogi:',~l~J~ic areas. Slrcam Imllution has occt~rrcd foamers. Very few foamers possess this valtutblc property, but both AI)OI'()ABI products biotic- grade re;MiN. Figt~rc 1 co,rip',ires thc C'k~torimctric ~'cst Nlctl~od results in biodegradability propcrlics of ADOFOAM and lhrcc other foaming agents. BIOD[:GI?AI)ABII IIY Of ['OAMIN(; A(;ENI,% i.- r~D 40 c9 . ~ 20 , t.c 0 ' ' I() ;q) 0 ,10 hO G() 10 80 qo MI (111¢,,) NALCO CHEMICAL COIVIPANY / PETROLEUM AND PRDI~EBB CHEMICAL DIVIf'41ON P. O, BOX 07 · SUGAR LAN[}, TUXAG 77470 ADOMITE MARK I1® WorM's foremos! flutd-loss add,t,ve for od fracturing ADOMITE® AQUA FludJoss add,bye for water-based tractunng Adom/te 0/I F/eld Chem/ca/s ADOMALL MtBl~ptJr[)ose ad(l~hve for water fraclur~ng IU,, ' ' ,' II ¢, A ~OCIETY OF PETROLEUM ENf 'ERS OF AIME ~260 North Central Expr~ .~ay Dallas, Texas 75206 THIS PAPER IS SUBJECT TO CORRECTION PAPER S P E Preformed Stab'l e Foam Performance I n Dr i I I i ng Eva lua inq Shal Iow Gas We l Is in Northeastern Alberta 5712 By Norman W. Bentsen, and Jack N. Ven.~, Chevron Standard Limited , (~)Copyright 1976 American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the Society. of Petroleum Engineers of AIME Symposium on For- mation Damage Control, to be held in Houston, Tx., Jan 29-30, 1976. Permission to copy is re- stricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is preSented. Publication elsewhere after p. ubltcation in the JOURNAL OF PETROLEUM TEChnOLOGY or the SOCIETY OF PETROL~]M ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate Journal, provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. I Abstract Conve~tional drilling and evaluating of shallow gas wells in Northeastern Alberta, producing from low pressure, fractured and vuggy reef formation proved expensive and provided.inconclusive re- sults. Preformed stable foam was introduced as a circulating fluid for drilling and coring the productive reef section of the hole. Production evaluation was done simply by picking up off bottom with the drilling string, shutting off the foam and blowing the well down. This technique proved to be inexpensive, fast, effective and non formation damaging. Introduction Development and exploratory drilling in the Call~.ng Lake - Algar Area of Northeastern Alberta :ln¥o]vcu pm~cbrat, ton a,~d cval~,~t:ion of' a nh,ti]ow, iow pressure, vuggy and 'I'm, ct, uteri root', Original procedures used conventional mud and/or water to drill 'this formation. Because of the large volume of fluid lost to the formation, incon- clusive DST and log evaluation results were obtained. In addition, a stimulation treatment and a lengthy clean up progr~n was required to obtain diagnostic evaluation results. Following the introduction of preformed stable foam as a drilling fluid, a continuous evaluation of the formation was obtained during dr$11ing. Histgry of the Program The original wells, House River 11-19-82-15 W4 and. Grand Rapids 11-25-83-14 W4, experienced severe lost circulation in the objective formation porosity. _Large volumes of drilling mud and lost circulation material were lost to the formation, resulting in mud bills of $2,800 and $10,500 res- pectively. Since then mud costs have been reduced to approximately $800 per well by using mud only on the upper hole. Due to the low reservoir pressure (200 psi at 1,000 ft.), low volume reservoir fluid output and flushing of the zone by mud and lost circulation material, no definitive results were obtained by drl, 1,],nl,~,m t,cnt, ll~g. Scvc~ mismu~s occurred ~n the llom~c l~Ivcr m~d (;rm~d ll~,.i)l,l wc.I]~ (m,)nl, l.y due to tool plugging) at a cost of $13,200 (rig cost not included). Approximately five rig days were used on these attempts. No reservoir fluid was re- covered on any of t. he DST's. As a rest~t, the Grand Rapids well was abandoned and the llouse River well was completed on log analysis only. Following move off of drilling equipment from the PREFORMED STABLE FOAM PERFORMANC~ .... SPE ~7±2 River 11-19-82-15 well, _.. attempt was made to prove the presence of gas. This involved blowing the well clean with nitrogen 15 times, swabbing four days and acidizing with 1,000 gallons of 15% HC1 to clean the well up suffi- ciently for a flow test. Overall cost of this clean up operation was approximately $30,000. results obtained on these two wells Chevron to investigate the use of a fluid that would permit underbalanced through the carbonate interval to: 1) Reduce overall expenditures 2) Prevent formation damage and flushing by foreign fluids, and 3) Evaluate the wells for possible gas and/or water influx as the formation is penetrated only drilling fluids available that would ire an underbalanced hydrostatic pressure in wells were straight air or an air lightened · Preformed stable foam was selected in )reference to straight air because of its greater carrying capacity and safety aspect for ing a down hole explosion and fire. It gave promise for cleaning out heavy oil present in the formation.. ram )hole Drilling typical drilling program consisted of cementing /8" surface casing at approximately 250 ft. in ~" hole and then nippling up an 8", 2,000 psi stack. Following this, the upper hole to the c was drilled using a standard low solids gel mud. At this point a suite of s was run and any zone of interest drillstem using LyneS inflatable test tools. Five ~one-half inch intermediate casing was then run · cemented to surface (Conservation Board re- uirement). ~This cased'off and isolated any gas and/or fresh water·sands. Section below Intermediate g the setting of intermediate casing, s (Figure //1) were ag. ain nippled uP. Initial- lng head and limited substructure height, .8" Grant Rotating Head was subst~tuted for the [{ydril and a 4" or 6" blooie line laid to the pit, Provision was also made to measure any as recovery through a 2" critical flow prover on the choke manifold. the W0C time, Air Drilling Services Ltd. 'licenced by Chevron Research Company) foaming !quipment was rigged up. Their equipment consist-~ of a portable 470 CFM WEKO Gardner-Denver air compressor equipped with a chemical p~np, tank unit and a quick coupling union discharge, all prepackaged on a hi-boy. This permitted very fast rig up on location and maintained air costs at a minimum of $1,800 to Sh,100 per well, de- pending on type and length of evaluation. After drilling out the float collar, cement and float shoe with water, the hole was blown dry with air. At this point Sulfotex or Adofoam foaming agent in water (1-1~ gallons per 10 barrels of water) was started into the airstream, and the hole drilled ahead, using a blended mix- ture of 150 to 350 CFM air at 250 to 400 psi and 12-14 GPM foamer-water mixture. Foam drilling usually proceeded in 10-30 feet increments. After each interval drilled, the foam was discontinued and the hole blown dry to · check for gas and/or water influx (Tables 1 & 2). This procedUre was followed as a check for the presence of water. Preformed stable foam masked low water volumes~ (10 to 20 bbl/hour) by com- pletely absorbing it. If gas was indicated, the air was also discontinued and the flow rate measured through a 2" critical flow prover. Stag~ drilling continued until water was produced or the producing zone penetrated. The well was then deepened for logging, and completed or permanent- ly abandoned as warranted. Later in the program, di~nond coring was initi- ated. This was successfully done, using a 4-27/32" x 2-1/8" core head and a 20 or 30 ft. core barrel. To accommodate this bperation, a change in wellhead equipment was required. After setting 5~" intermediate casing, the 8" BOP stack was laid down and a 6" stack (Figure #2) nippled up. Addition of the Hydril to the stack per- mitted stripping the core barrel in and out of the hole, an operation which could not be done through the rotating head. The 2-3/8" I.D. rubbe~ in the rotating head would accommodate the 2-7/8" tubing, 3~" DC and Kelly but would not pass the stabilized core barrel. · DUring coring, drilling and tripping operations' the well was continually blown to flare. Rates varied from nil to 5 MMcfd. Efficient, safe operations were maintained for all phases of the operation regardless of gas production vol~nnes. Tripping a) Tripping In: When out of the hole with the drill string, the well was closed in with the blind rams. To trip in, the well was opened to flare through the choke manifold, and the core barrel lowered into the rotating head and Hydril. A Baker float sub and insert was Spw. 5712 installed on top of the core barrel. The Hydril was then closed on the core barrel and the blind rams opened. The core barrel was then stripped in through the closed Hydril. Following the core barrel, the 3~" drill collars were picked up, stripped through the rotating head rubber which in turn was locked into place in the rotating head. The Hydril was then opened and the gas allowed to flow through the blooie line permitting closure of the choke manifold. The balance of the string was then stripped into the hole. b) Tripping out: To trip out, the reverse procedure was followed. ]oring ~he Paleozoic (Grosmont) formation consists of a £ractured and ~uggy limestone or dolomite. 'Coringl ~as normally done using a 4-27/32" x 2-1/8" core head and a 20 or 30 ft. core barrel. Penetration Cates varied from 5 to 16 ft. per hour at 4-6,000# ~t. 'and 70 to 100 rpm. Initial recoveries ranged from 60 to 100%, depending on rug size. Jamming occurred every 2 to 10 ft. In an effort to improve recovery and reduce jam- ming problems, larger hole was drilled on two wells. This permitted cutting a 3~" core with a 6-7/32" x 3~" x 30' core barrel. No improve- ment was noted until the core barrel stabilizers were removed and replaced by slick subs. This ~ction was taken to facilitate safer stripping of the larger core barrel. Following this, three 30 ft ~ores were cut with 100% recovery on each. On the next well, the small.core barrel was again ~sed but with the stabilizers removed. Jamming .oroblems were reduced and a good improvement in ~ore recovery was also noted. Drilling The Grosmont was normally drilled with a 4-3/4" mill. tooth type rock bit carrying 7-8,000# wt. and 7-80'RPM. Penetration rates varied from 7 t,o 1,6 ?'t. per tlour d.apet~di.~ or~ roe? 'poros:l.l;y. ~'oam vol~r~es consisted of 12-1)1 (J['M £'omr~er-watei' mixture blended in 150 to 350 CFM air. Air rates were varied, depending on the amount of water produced. These rates gave good hole cleaning and provided e×.cellent drill samples. ~esting Evaluation of the foam drilled reef involved blow- 'ing the hole dry of £oam every 10 to 30 ft. turning the flow through the choke manifold and aeasuring any gas flow through a critical .flow BENTSEN <--~. 215 prover. With this procedure, a stabilized rate could be obtained in less than an hour as no fluid had invaded the formation to create damage or flushing. Penetration of the aquifer was also easily detected by the immediate presence of wate~ production. Logging Normally DILL and CN-FD-GRC logs were run at intermediate casing point and again at total dep- th. To log the Grosmont section below intermedi- ate casing, the rotating head was removed and a ' 40 ft. lubricator installed for logging under pressure. Sonic and radioactive type logs were run under dry conditions. For running the DILL, a small amount of water was pumped into the hole to provide a logging media. Corapleti.0n After logging operations had been completed, the rotating head was reinstalled. 2-7/8" production tubing equipped with an Otis "N" nipple and "CN" Otis retrievable plug installed in the first joint was then stripped in to bottom. The hole was blown dry with air, and gas measurements re- corded. Tubing was then relanded above the open hole (Figure 3). Finally BOP's were removed, the top section of the wellhead installed and the "CN" plug retrieved on wire line. Conclusions Altering the drilling program ts a controlled underbalanced operation incorporating preformed stable foam as a drilling fluid, has: 1. Reduced mud costs. 2e Eliminated time consuming conventional DST procedures and costs by providing a system that gave a continuous formation evaluation during drilling. 3~ 4~ Given immediate and accurate evaluation results by eliminating formation damage and lengthy, expensive formation clean up operations. Reduced permanent formation dam~age due to f'orln~l;i~l ?]ll:;)~i~u.~, ~l.~l pq~l~gi~ll~, by excess- iv(~ vr)lu)m~:: ()1' waLu~', mud culation material. 5. Reduced comp'l, etion costs by as much as $30,000. Acknowledgments The authors wish to thank 'the management of Chevron Standard Limited for permission to publish this work. The assistance and contri- butions of members of the Engineering Division PREFORMED STABLE FOAM PERFORMANCE~__ SPE ~712 216 is also acknowledged. References 1. Christensen, R. J., Connon, R. K., and Millhone, R. S.: Applications of Stable 2, Foam in Canada, Oil Week September 20, 1971. Anderson, Glen W.: Stable Foam Circulation Cuts Surface Hole Costs, World Oil September 1971. TABLE 1 - FLOW TEST IN A DRILLED SECTION Algar 6-32-82-16 De~t~ Time-Min Orifice 93O 94o 95O 97o lOO0 1040 1090 117o 30 3O 6O '60 6O 6O 45 6O Pressure psig 1/2" NIL 1/2" NIL 1/2" 25 1/2" 56 3/4" 70 3/4" 65 3/4" 65 3/4" 25 Recovery NIL Slight Puff 205 Mcfd 367 Mcfd 988 ~cfa 930 Mcfd 930 Mcfd 461 Mcfd TABLE 2 - FLOW TEST IN A CORED SECTION Algar 6-14-83-16 Depth 914 944 971 977 Time-Min Pressure Orifice psig 120 min 1/2" 11 60 1/2" 11 60 1" 99 60 1~" 70 Recovery 121 Mcfd 121 Mcfd 2500 Mcfd 4946 Mcfd _, ~' ....... \ ROTARY TABLE ,. ~/~ ~ TO PIPE RAMS ~ /" 500 PSi --, ~ (-F~)r .'._ \, ,H~N~/'~>/J ~ CASING BOWL Fig. 1 - Shallow gas 8" blowout preventer hook-up. ......... I 7" x 4" SWEDGE 7 ..... 6" 600 SERIES GRANT ROTATING ' 300 PSI - 4" GATE VALVE HEAD 4" FLEX HOSE "~ ' G" 600 SERIES MSP HYDRIL L/l ' ~," 16oo-,~oo) I , ' [,_.,.H ~EQUIRE 8.823 ~T. MIN. FROM BOTTO~ OF CAaING HEAD TO TOP OF ROTATING MEAD (105.e75" OVE~ ALL) Fig. 2 - ~p stack for shallow gas project during foam drilling or coring while flaring ~as ~'rom annulus. SERIES 2M WELLHEAD GROUND LEVEL 8 5/8" CASING IN 12 I/4" HOLE + 250- 5 I/2" CASING IN 7 7/8" HOLE 2 7/8" TUBING 2 7/8" OHIS TYPE 'N' NIPPLE TYPE 'CN' PLUG TOP OF PALEOZOIC- o4 3/4"OPEN HOLE Fig. 3 - N. E. Alberta typical well completion shallow gas well. OIL&GAS JOURNAL II Preformed stable foam aids workover, drilling S. O. HUTCHISON G. W. ANDERSON Standard Oil Co. of Calif. PREFORMED stable foam as a cir- culating fluid for workovers and drill- ing has achieved a remarkable record in the short time it has been available to the industry. Some of its accomplishments are: · Foam recomplet, ion costs 30% less and has produced 33% more oil than new wells drilled in with clay- base mud. · Near-gauge holes have been drilled in permafrost where conven- tional fluids cause excessive hole en- largement. Increased penetration rates have lowered costs about $15,000/well. · Surface hole and top-hole drilling in West Texas were successful where air drilling failed due to wet forma- Foam recompletions and new wells Figs. 1 & 2 Permafrost drilling 30" conductor ~ 78', d*v. 174 Fig. 3 '. :' :I': 200 400 600 i fao --t-- : 0 : i0 X Foam drilled !>' Permafrost to 350' ~. 495' ia .___k l?,/F~i?~,,~ Gas sand . ~ ~ Fomn drilled ..... ~ ~~ (ha.qod 811 No:.2 5~- od n'ud il°'' 400 I'''l) I 1'/¥' X ~ Mud drilled ~ ~ ~ ?41' In ID/, h, 0pon~.rh ltl, Io ~ ~ Ay 6.3'/h, l/V:' ~10[otloll IIIIII Ada. I lImo all foam drilling loam and mud ddlllflg 20 "v 30 40 50 ':.:"'"60 ..... ~70 80 ' Rotating time, hr OGJ · ~ tions, and drilling costs were re- duced from $19 to '$6/ft. · Hard-rock porous formations have been drilled and evaluated without formation damage caused by over- balancing drilling fluids. · Computer programs permit anal- ysis of circulating pressures where gas, foam, or liquids are used. · The combination of improved hy- draulic snubbing equipment or reeled pipe with preformed stable foam has created a whole new dimension in well servicing where costs can be reduced, safety improved, formation damage eliminated, and ecology preserved. Re;completion vs. new wells. The wells drilled in the late 1800's and early 1900's in California's low-gravity oil fields were generally completed with liners having large perforations or slots which were adequate and de- sirable for primary production. However, these large perforations allow little or no sand control and ex- cessive sand producti6n becomes a major problem when the crude oil's viscosity is lowered in place by steam injection. One solution to the problem was to drill replacement wells equipped with fine-mesh slotted liners. This required abandoning the old wells which could be very costly--averaging about $2,000/well. A more economic solution was to pull the old liners using the thermal assist technique discussed earlierJ and drill in a new fine-mesh slotted liner with preformed stable foam. Table 1 compares the cost and pro- duction of 68 wells recoml)leted with foam anti 42 n(:w wells COml)leled with clay-I)asc n~ud. As indicated, $3~;8,832 was :;aw,d I)y hal havinl; lo tel)lace lhc 68 old wells with new wells and an ad- clilional $1:16,01X) w~s saved by not having to abandon the old wells. The average cumulal, ive production for the first 24 months cam.pares 21 weslcrn I'ctrolct,m Short Course, Lubbock, Apz. 20-21, t,ndcr the original title "Pre- formed Stable i"oam: Thc New Approach to Big tiole Drilling and Slim-Hole lligh- Pressure Cleanouts." Foam Vs. air drilling 300 400 50O 700 800 900 Pecos County, Tex. Reaming ~ Air drilling X 4n0o~ ~. % Bit No, 1, 20" hole drilled ~ ~ Foam drifting with elf ~ ~ 700 dm, 12 gpm ' ~i 60 rpm, bit wt 60,000 lb Est. 200 bbl/hr formation water Bit Mo. 2- 20" 493' in 42t/2 hr 1% fo~m sol'n ~ Bit ~1o. 3- 20" N227 ft in 261/2 hr 1 &" csg Time, days Fig. 4 Foam vs. mud drilling Fig. 5 1,000 2,000 3,000 4,000 5,ooo 6,000 7,000 8,000 Pecos County, Tox. 0"::' 20 '" , ' 40 ' 50 .... 60 ':/'.7' 70- Drilling time, days . . ,'~ foam-recompleted wells and 10 new wells in a steam-drive section of the Kern River field where the thermal and energy levels were fairly uniform. The foam-recompleted wells averaged 5,771 more bbl oil over the 24-month interval which increased income by $240,382. Fig. 1 shows average daily produc- tion of foam-recomplet, ed wells vs. new wells. It was estimated earlier,' from limited data, that formation damage resulting from the use of 'clay-base drilling fluids could be removed by steam drive in 10 to 12 months. How- ever, additional production history in- dlcales 'llml nltlcli moro IJln('~ Is (Iulr(~(I, i)l'()lml)ly 2t) I~) 2,1 b(,rol,e ('()IIIIIItI()LIS SI(;lilil inj('cti(m effectively remove the clay-base drill- ing fluid formation damage. A similar study was made of new wells and foam recompletions in a field on the west side of the San Joaquin Valley in California. Fig. 2 shows average daily production after the first steam cycle. The cost of recompleting an old well' with stable foam was 26% less than the cost of'drilling a 'new well. However, the most significant factor was the first 10-months' production after steaming. The foam-recompleted wells averaged a total oil production of 8,301 bbl while the new wells made only 2,827 bbl. Recent new wells com- pleted with preformed stable foam in these low-pressured, low-gravity reservoirs have shown excellent initial production responses to cyclic steam stimulation. Permafrost drilling. Laboratory tests and field trials of preformed Stable foam at elevated temperatures proved that higher bottom-hole circulating temperatures could be realized than if raw steam were used as the clrculat- hlg fhli(I, Il was concluded fr()m Ihose t~l~(*l'llllt'lllN Ilml slnl)h, I'()llll! hlih' ;1 h)w Ileal t:tll)llclty lind is Il poor c. oll- ductor of heat. It was decided that the thermal properties of preformed stable foam should be investigated ,in the low- temperature ranges for use as a drill- ing fluid to drill large-diameter holes in permafrost for surface casing. Lab- oratory tests with simulated perma- frost cores were conducted with en- couraging results. The first cold-foam field trial was conducted by Chevron Standard Ltd. in the Canadian Arctic in January 1971 with outstanding results.2:~4 Fig. 3 is a plot of drilling times achieved with preformed stable foam and lightweight mud. Full-size 17~/~ in. hole was drilled with preformed stable foam at pene- tration rates up to three times faster and no hole deviation problems were encountered. Caliper logs indicated no significant washed-out sections through the permafrost. While taking a deviation survey in this well at 699 ft, formation gas un- loaded the foam from the annulus and was (lelected at the bloole line. i:or snf('ly, Ih(; gas wns fhir(;(I ill Ih(~ I)hn)i(, Illl(, 150 I'1 I'l'~)ll! IlIo rip,, A ('11(,¢'1~ wily(' I,l,';Inlh~(I IIIgh Ill Ill(! drill slrhlg prevented back flow and the rotating head diverted all returns out the blooie line. Apparently the preformed stable foam entrapped all produced forma- tion gas while circulating, but there was sufficient formation pressure for the gas to unload the well after cir- culation was stopped. This is an excellent example of the safety that can be realized by using preformed stable foam. However, Comparison of foam recompletions vs. new well costs · .Foam recompletions · New wells Property 1'.t3. wells Total cost, $ Av. cost/well, ~ '~No. wells Total cost, $ Ay. cost/well, $ 'A ....... ' ....... 41 B ........ 9 C ..... 10 D ........ 8 68 453,150 11,052 22 350,979 135,681 15,075 3 49,054 138,171 13,817 17 341,918 105,437 13,179 . · -- 832,439 12,241 42 .741,951 Indicated savings: 68 × $5,424 -- $368,832 Possible savings on abandonment: 68 × $2,000 -- $136,000 Comparison of foam re.completions vs. new well production Cum. prod. Ay. cum. Cum. prod. Property No. wells 1st 24 mo., bbl prod/well, bbl I~. wells 1st 24 mo., bbl Table 1 Foam · recompletion Savings, % 15,953 31 16,351 8 20,112 31 In 10 pattern steam drive 21 484,432 23,068 10 172,976 Value of improved pror~uction in 10 pattern steam drive 5,771 bbl/well × 21 wells x $2.00/bbl = $240,382 17,665 30 Foam Ay. cum. recompletion prod/well, bbl gain, % 17,297 +33 Licenses granted by Chevron Licensees Major Operating Area Table 2 Sierra Production Service Lunn Production Service California Production Service Border Drilling Co. Pool Co. Skinner Drilling Co. Servicios Hydrocarb Baker Oil Tools Halliburton (Otis Engineering) Air D~illing Services Foam Circulation, Inc. NOWSCO Central California Central California Southern California Central Canada West Texas & Wyoming Trinidad T~inidad & Venezuela California & Gulf Coast California & Gulf Coast Canada, Rocky Mountain Area & Alaska West Texas California & Gulf Coast since equipment was not available on this first field trial, either for safely round-tripping the bit or for detect- ing formation gas in the returns, it was decided to kill the well with mud before drilling ahead. The hazard po- tential of encountering shallow gas sands was further emphasized when 400 bbl of 8.8 ppg mud was lost be- fore circulation coUld be established. .Serious surface-pipe ,problems have developed in some of the completed North Slope wells. It is believed cas- ing collapse has been caused by re- freezing of water-base mud left in the annulus between the permafrost and the 20-in. casing. Diligent .efforts have been made to completely displace this mud with either cement or oil-pack fluids. How- ever, these viscous fluids tend to chan- nel through the washed-out areas, leaving freezable fluids in the annulus. Preformed stable foam drilling should provide an excellent solution to this problem. A hole drilled through permafrost with preformed stable foam .should be near-gauge, and the denser fluids, such as cement or oil- pack fluid, should give more nearly a 100% displacement. Laboratory tests indicate that even water will float preformed stable foam out of large bulbs efficiently,a Preformed stable foam should not present any ecological problems since it is composed of a large volume of air with a small amount of freshwater and a very small percentage of bio- degradable surfactant. West Texas top-hole drilling. Fig. 4 compares preformed stable-foam drill- ing rates vs. the best air-drilling rates in 20-in. surface hole in Pecos County, Tex. This well was spudded with air, but i.t soon becazne evident that 4,000 scfm of air could not develop enough annular velocity to efficiently clean 20-in. hole. Preformed stable foam drilling was started with 700 scfm air and 12 gpm foam solution. The hole cleaned up quickly which permitted drilling ahead to 1,000 ft in record time. After cementing' 16-in. surface cas- ing at 1,000 ft, an attempt was made to drill a 14~-in. hole with air, but the formation was too wet to permit ,effective hole cleaning. Preformed stable foam was then used to drill to 5,800 ft in a record 24 days. In this area, the best previous light- weight brine-mud drilling time to 5,800 ft was 53 days, Fig. 5. At this point preformed stable foam drilling was discontinued due to excessiwe fill after trips. This well was drilled with fresh- water foam which reacted with water- sensitive shales causing severe hole enlargement. Since the drilling of this well, more stable saltwater foamers have been developed along with cer- tain foam additives which should solve this hole-enlargement problem and permit preformed stable-foam drilling to greater depths to take ad- vantage of these outstanding penetra- tion rates. Drilling with preformed stable foam in the interval from 1,000 to 5,800 ft reduced the drilling cost from $19/ft for mud drilling to $6/ft. The use of preformed stable foam for drilling in this well resulted in an over-all sav- ings of $75,000. Hard-rock drilling. Preformed stable foam has been used to drill into lime- stone and dolomite reservoirs in Colo- rado with penetration rates up to four times faster than mud drilling while permitting instantaneous porosity eval- uation. Normally, wells drilled with Nomograph scales mislabeled TttE homograph for equivalent value of olefin-plant feedstocks on page 85 of the April 24 issue is in error as printed. The three righthand scales should be laheled propane, butane, and propylene. In the printed version, the scales are erroneously labeled for ethane, propane, and butane. lightweight muds lose circulation wnen porosity is encountered, when then requires massive acid treatment to permit evaluation. A recent preformed stable-foam drilled well came in for 650 bo/d without acid treatment. A fractured cherty shale producing zone in Santa Maria, Calif., has been drilled with preformed stable foam in- creasing penetration rates up to five times while using only one-fourth as many bits as the best well drilled with clay-base drilling fluid. Her'e, too, drilling with muds causes severe formation damage which must be re- moved with massive acid treatments to achieve production. The preformed stable-foam com- pleted wells were producing oil while being drilled and came in immediately after completion without acid ,treat- ment. Improved snubbing units. Preformed stable foam was first used in conjunc- tion with a hydraulic snubbing unit for remedial work on an artificial island off the coast of California in November 1968.4 This initial work in- dicated that several improvements in the snubbing equipment would be re- quired before efficient well servicing could be accomplished. The improvements incorporated into the hydraulic snubbing units to fa- cilitate complete well servicing were: new tubular aluminum mast designed for 1,000-lb hook loads; a rotating head assembly was added to permit rotation of the work string for drilling cement plugs and hard sand fill; the unit was reunitized into 10,000-lb pack- ages for faster rig-up and to permit offshore platform on and off loading with existing cranes; a larger hy- draulic power unit was added to in- crease pulling capacity to 140,000 lb; larger hydraulic cylinders were in- stalled to permit handling 3½-in. OD tubing; and a large-diameter lubri- cator was designed to be'held in the snubl)er pipe rnms lo permit lhe run- ning of wire-line tools and packers through the uult. Onshore snubbing work.' Improved hydraulic snubbing equipment has been used on 10 onshore wells. Six jobs involved the circulation of pre- formed stable foam to remove sand and debris from wells to depths of 11,466 ft, annular clearances as-low as 0.051 in., and injection pressures to 2,500 psi. Sliding sleeves were actuated and gas-lift valves were in- stalled in one well which was so devi- ated that wire-line tools were ineffec- tive.. Tubing was changed out in three gas wells where maximum casing pressure was 1,500 psi. Previous tub- ing changes using conventional well servicing equipment required killing fluids which resulted in severe damage to gas-sand permeability and loss of commercial production. The first use of preformed stable foam with the improved hydraulic snubbing equipment was on a newly completed dual zone well, Fig. 7, Well A, which had developed a packer leak. The well was killed with calcium chloride water to pull and repair the packer. After recompletion it was found that the lower oil zone would not flow even after swabbing, rock- ing, and blowing with gas. Then Mn. tubing was snubbed into a 2%-in. tubing against 300-psi well- head pressure. Preformed stable foam. circulation was established with gas from the upper zone at a rate of 80 scfm and 15 gpm foam solution at 2,100-psi injection pressure. A total of 63 ft of sand and mud was cleaned out along with calcium chloride killing fluid. After cleanout the circulating pressure was 575 psi with 57-scfm gas and 6-gpm foam solu- tion, but the bottom zone was still too badly damaged to flow. Acid was pumped down the tubing annulus to remove ,the formation dam- age caused by the killing fluid. An at- tempt was made to unload the spent acid by injecting gas down the 1-in. tubing string at rates up to 880 Mcfd but only 10 to 15 bbl of fluid could be unloaded. Preformed stable foam circulation was established with 74 scfm gas and 15 gpm foam solution at 2,425 psi, re- covering acid, salt water, and oil. Foam circulation was continued for 20 hr to thoroughly clean the well. After clean-up the stable foam rates were ;19 scfm gas with 6 ?.pm foan~ solution al ,180 psi wilh abtmdant oil in Lhe returns. Foam circulation was discontinued and the well continued to flow with an initial l)roduction rate of 377 bo/d and 512 Mcfd gas at 5~ psi. The total cost of this 92-hr job, in- cluding acid, was $10,500. O~Jshore removal ~rk. The im- proved' hydraulic snubbing unit with a preformed stable foam circulating system was used on 24 jobs on two offshore platforms. Work strings of aA and 1-in. pipe were run inside of 2¢~ and 2~/a-in. tubing. Preformed stable foam was cir- culated while removing sand, and cement; milling-up stuck valves and wire-line tools; fishing and washing over stuck bailers; cleaning out after perforating and unloading spent acid. Gas-lift gas was used to generate the preformed stable foam. Injection pressures ranged from 650 to 1,800 psi at depths of 3,030 to 9,200 ft. The total cost of the 105 days of work on these 24 jobs was $140,000, including all marine transportation. The newly unitized snubbing equip- ment can be transported in one trip by a small work 'boat and off-loaded at the platform with available cranes. !n contrast, the marine transportation and crane service required to round- trip a conventional workover rig and circulating system costs approxi- mately $155,000. The production recovered by ser- vicing these 24 wells was 613 bo/d and 1,688 Mcfd gas which could not have been realized at this time be- cause permits for using conventional hoisting equipment could not be ob- tained. Offshore recommendations. Two sup- posedly simple recbmpletion jobs de- veloped unexpected problems after work began which points up the ver- satility of the improved hydraulic snubbing units. These wells initially were to be a simple recompletion in- volving pulling the tubing string, running bridge plugs to abandon the lower intervals, and rerunning the tubing for perforation of a new zone with through-tubing guns. Well P. After the snubbing equip- ment was rigged up over the hole it was found that the packers could not be pulled within the tensile strength of the 27A-in. J-55 tubing string. Tub- lng was cut above the top packer wilh a (~h(,~ni('al cut. let and the J-55 I. ul)inll was I)ullcd. A fishinl; slriul,, with overshot, buml)er sub, hydraulic jars, three 4:¼-in. drill collars and an accelerator was run on 2~s-in. N-80 tubing. The fish was en~,,ag(:d and jarred up to 100,(X)0 lb without avail. A more powerful hydraulic power unit was installed which permitted jarring up to 125,000 lb and pulling to 135,000 lb, but the packers still could not be pulled. A free point indicator was run and Offshore recompletion, Well R Fig. 6 :5 3" tubing 21/2" J-55 T' casin~ Sliding sleeve Boll volvo 212' Premature set wire- line bridge plug 5,505' Tubing parted 6,784' Milled slips with Dynadrill Pushed to : TO 7,348' '. :~: 212' Run 27/8" x 4" concentric tubing wilh boll volvo lo permi! fulure snubbing Ran ~odel K packer 6,812' Set wire-line bridge plug 6,885' OGJ a chemical cut made between packers. The fishing tools, top packer seal as- sembly, three sliding-sleeve valves, and two gas-lift mandrels were re- covered. The lower intervals were abandoned. The 27~-in. J-55 production string was rerun with gas-lift mandrels, sliding sleeves and seal assembly, and landed in the top packer. A 4 by 27/s- in. concentric-tubing ball valve assem- bly of new design was run on the top of the production string to permit future snubbing without killing the well. Previous ball valve assemblies with a ~¼-in. external hydraulic line re- quired killing the top portion of the well for removal before snubbing op- erations could be started. This com- plete workover job cost $25,500 and tool( 13 daylight tours. Well R Fig. 6. While trying to unseat the packers, the tubing parted at a sliding-sleeve valve. Fishing tools consisting of overshot, bumper sub, hydraulic jars, and drill collars were run on N-80 27~-in. tubing. The fish was engaged and jarred free at 100,000 lb. The fish was pulled recovering the retrievable packer and lower seal assembly. A 7-in. bridge plug was run on wire line and accidentally set 1,400 ft above the programmed depth. Re- trieving tools were run on 27~-in. tubing but the bridge plug could not be released or moved and only the setting tool was recovered. A circulating pump and tank were moved onto the Platform and filled with sea water. A 6-in. concaved mill was run on a 5-in. straight hole Dyna-Drill with float sub, two junk subs, and one 4½-in. drill collar with stabilizer on 27/s-in. N-80 tubing. After milling for 1½ hr circulating seawater, the bridge plug dropped down the hole and circulation was immediately lost. The bridge plug was pushed down the hole with the Dyna- Drill to the bottom packer. Preformed stable foam could have been used to run the Dyna-Drill since it is a positive displacement-type mud motor. I lowever, in this well the lower zone was lo I)e al)andonc'd so lost circulation was not critical. After a casing-scraper run, a sec- ond bridge plug was set at the desired depth and tim production string with sliding sleeves, gas-lift mandrels, and production packer was landed. This work required 31 daylight tours and cost $50,000. The last offshore work done with conventional hoisting and circulation equipment on these platforms was in '1968. One comparable job, involving kill- ing with salt water, circulating to re- mo,,,, gas, packer milling with a Dyna- Drill and perforating extended over twenty 24-hr days at a cost of $77,000, including a prorated marine transpor- tation cost of only $6,769. Elk Hills packer-snubbing program. Hydraulic snubbing equipment was used at the Elk Hills Naval Petroleum Reserve No. I to pull tubing and rerun with packers in' 184 wells with- out killing the wells.° An additional 33 wells were serviced with snubbing equipment but required killing with salt water because of the type of existing wellhead equipment or for well logging. The density of killing fluids used in these wells was carefully designed to provide a maximum 100-psi overbal- ance. However, even with this close con- trol of killing fluid density, an average of 28 bbl of salt water was lost in 14 of the 28 wells killed. Killing the wells with salt water cost on an average $850 more per well than snubbing under pressure. Safety. The improved hydraulic snubbing units have an outstanding safety record--over 259 jobs without a blowout or lost time accident. Probably part of this safety record is due to the redundancy of BOP equipment available when a snubbing unit is used. Generally, and particular- ly offshore, the snubber is rigged up on top of a full BOP stack, including GK-Hydril bag, double pipe rams, and complete shutoff rams. Since the snub- bing equipment includes two pipe rams and a stripper, there are at least five annular closing devices on the well. The BOP stack and snubber stack have independently hydraulic power systems. Another factor which contributes to safety is that preformed stable foam can be circulated from the wellhead through a high-pressure trap into existing production facilities for sepa- ralion into gas, liquid, and solids, and clisl)()sal lhroul4h the gathering systenl. Working with wells under pressure requi]'es that persc?nnel phtn carefully and proceed with a caution that con- tributes to safety. Reeled-lubing work. The combination of reeled tubing with preformed stable foam as a circulating fluid has de- veloped into a useful tool for specific applications. Previous attempts to un- load fluids such as spent acid, salt water, and oil from Iow-pressured wells with high rates of nitrogen were Unsu~ccessful. At these high nitrogen rates, the hydrostatic head of lifted fluid plus annular friction exceeded bottom-hole formation pressure and fluid was pushed back into the forma- tion so only a small slug could be unloaded before gas breakthrough. When nitrogen rate was reduced, the lower velocity would not carry fluids. Well B. Fig. 7 is an excellent ex- ample of how the combination of reeled tubing and preformed stable foam can permit well stimulation with- out killing the well and causing further formation damage. Well B is a single zone completion in the upper high GaR sand in the same field as Well A. After several years, the producticn had declined to 37 bo/d and 748 Mcfd at 480 psi. Build-up tests indicated severe formation damage, but a po- tential of 2,100 Mcfd at 1,200 psi. Acid was pumped down the annulus between X-in. reeled tubing and the 2%-in. production string. Preformed stable foam circulation was estab- lished at 3,500 ft with 100 scfm nitro- gen and 4 gpm foam solution at 1,000 psi. Acid-cut foam surfaced in 23 min. Reeled tubing was run at 40 to 60 fpm while maintaining constant foam circulation with 150 scfm nitrogen and 4 gpm foam. solution. At 8,480 ft, a maximum injection pressure of 3,330 psi was reached and the well started to come in. Annulus back pressure of 300 psi was maintained for well control and injection pressure dropped to 1,750 psi at 9,860 ft. As the well unloaded, back pressure was increased to 550 psi and the injection pressure dropped to 1,400 psi. After a total of 5 hr of foam injec- tion, the pH of the returns increased to 7.0, indicating complete acid recovery. This initial production was 1,900 Mcfd at 1,150 psi, indicating excellent for- mation damage removal. Total cost of the job was $5,507, including acid, reeled-pipe unit, and 75,000 scf of nj trog~'n. Another well in the sa~ne field had loaded up and died while producing to a 500 psi separator. After low-pressure surface facilities were ins'tailed, aA-in. reeled tubing was run inside the 2%-in. tubing and circulation was established with preformed stable foam in 15 min. Reeled tubing was run at 40-60' fpm to 7,800 fl while maintaining contin- Uous foam circulation. The well un- loaded and began to flow. Foam circulation was stopped and the reeled tubing was withdrawn from Stimulation with preformed foam Fig. 7 ~ 2a/~" tubing 5~/~" casing 1" OD tubing Sliding ~ sleeve 9,280' =~ 1.88" ID __ : Sliding sleeve 9 1'18' ~ , Permatrieve ~ packer 9,153' ~ Upper 9,22S' Carneros 9,260' a/e" reeled tubing Eff TD 9,863' Well B 9,934' the well. Initial production was 220 bo/d and 250 Mcfd gas at 300 psi. The total cost of this safe and effective method of unloading a dead well was $2,141, in- cluding 26,000 scl of nitrogen. The maximum nitrogen injection pressure used for forming preformed stable foam in the field has been 3,800 psi, and 10,000 psi during a controlled test in the shop area. Fo'am circulation atmlysis. A com- . purer program has been developed by Chevron Oil Field Research Co. which can analyze a circulation system to determine injection pressures, bottom- hole circulating pressures, foam qual- ity, and lifting ability--plus annular velocity and circulating times at vari- ous gas and foam solution rates and annular back pressures. 'l'ht~ program (!onsi(lers liquid and gas entry from the formations, foam temperature gradient, penetration rate, and formation solids density. De- viation effec:ls of directional holes and the excess tubing on reeled' pipe jobs are also taken into account. This program has proved successful in design of gas volume and pressure requirements to get maximum hole- cleaning ability with foam. With ap- propriate wellhead and back pressure controlling ,equipment, foam-circulat- ing systems can be designed to main- tain specific bottom-hole circulating pressures. While this program was designed primarily to handle stable foam, it can be used to analyze the circulation of gas, liquid, or any combination of gas and liquid. Licensing. Licenses under patent rights and technical information to use preformed stable foam have been granted by Chevron Research Co., the research and development subsidiary of the Standard Oil Co. of Calif. to the companies listed in Table 2. References I. i lulchison. S. O.: Stable Foam Lowers Production, I)rilling and I~emcclial Costs, 17th Annual Southwestern Petroleum Short Course, April 1970. 2. Anderson, G. W.: Slablc Foam Circu- lation ('Ills Surface i lole ('osls, World Oil, Ihlt,ugh I'ctinal'losl. ()il nmi (ins Journal, hcpl. 2o, 1971, p. 128. 4. ('hristenscn, R. J.; ('Ollllt)ll, I{. Millhone, I{. S.: Applications of Slable Foam ill ('anada, Oil Week (('anada), Sept. 20, 197I. p. 30. 5. }ltHchi~ol~, S. {).: I:oam Workovcrs C'osts 50%, World Oil, November 1969, p. 77. 6. Snydcr, l{{~bcrt E.: Snubbers, l{celcd Pipe Units Feature Portability, Safety, World Oil, December 1971, p. 41. 7. Young, S. A.; Butch, W. it.; Muse, J. F:. Packer Snubbing Program Protects Elk ltills Wclls~Turnkey Contract Reduces Costs, SPE Paper No. 3187, 41st Regional Meeting, Santa 'Barbara, Calif., Oct. 29-30, 1970. Charts help find volume, pressure needed for foam drilling ,}ACK A. KRUG DR. B. J. MITCHELL Colorado School of Mines Golden, Colo. FOAM is accepted as an aid to drilling in a variety of situations. In air-drilling operations, it can help stabilize sloughing formations, aid in the removal of cuttings in the presence of water, and assist in the removal of water through natural flows. Used with mud in a conventional drilling-fluid system, it can effectively lower bottom-hole pressures. But there has been little information available on a fundamental engineer- lng approach to use of foam. The the- ory and solutions presented here for the application of foam as a primary drilling or workover fluid should help the drilling engineer make the best use of these systems. Operating parameters for foam in workovers or drilling include: · Injection volumes of air and wa- ter · Injection pressure · Penetration ra[e · Depth Other key considerations include: minimum annular r e t u r n velocity; maximum foam quality; bottom-hole pressure; and minimum required horsepower for injection. These factors are complicated by the physical characteristics of foam and the well bore. It must be realized that foam is a Bingham plastic fluid that compresses as it flows down the drill pipe, and expands as it returns, carrying cuttings up the annulus. Foam characteristics. In this study, foam consists of air, a surface-active agent, and water. The surface-active agent and water are the continuous phase while the air appears as discon- tinous bubbles. In contrast, mist is a fluid consisting of same components but the air appears as the continuous phase and the aqueous solution as droplets. Recently, MitchelP has shown that foam is a Bingham plastic fluid in the quality range of 60 to 96% and is a Newtonian fluid in the quality range from 0 to 60%. He also showed that foam converts to mist if quality ex- ceeds 96%. Quality is the ratio of air volume to air and water volumes. The Bingham plastic equation~- is: · - ry = ~,d,~'° (1) Where: r = shear stress, psi or Ibf/sq ft r~. -- yield shear stress, psi or Ib~/ sq ft /~p -- dynamic plastic viscosity, cps or lbm-ft sec ----. shear rate, sec-~ Fig. 1 Stress, viscosity Foam region Mist region~ , Dispersed I ._o_ I , bubble I -~ ~ Source: Mitchell, 1970b 0,2 0,4 0.6 0.8 1.0 Foam quality Suurce: Mitchell, 1970b~ , Conclusions' from this study of foam applications · Air and water volume rates for foam drilling operations can be specified. · Bottom-hole pressures and injection pressures can be cal- culated. · Minimum hydraulic h()rS('l)()w('r fc)r a fi)am drilling 0l)era- tion will occur when the annulus back pressure is 14.7 l)sia. · Any deviation from the specified minimum hydraulic horsepower will require additional air volumes, water volumes, and injection pressure. · As depth increases, higher injection pressures and larger air and water volumes will be required. · Circulating l)ottom-hole pressure increases with depth and drilling rate. · Higher .penetration rates will require an increase in the in- jection pressure and no practical change in the injection air and water volumes. THE OIL AND GAS JOURNAL--FEBRUARY 7, 1972 61 Figs. 2 and 3 show the relationshiI.~._ betWeen foam quality and yield stress (r:.) 'and plastic viscosity (/~p). Model development. Two differential equations result from the mathemati- cal model developed to describe the flow of foam during drilling--one for the flow in the pipe, and one for flow in the annulus. The differential equa- tions are explicitly expressed in terms of pressure and depth, and are numer- ically integrated over the full length of the pipe and annulus with a constant. pressure increment. The Buckingham-Reiner equation:~ developed through their model de- scribes the flow of a Bingham plastic fluid in a pipe as: 7rR4 (Po--PI,) [- 4 + Q '-- 8/.~pL 3 -- ( ) (2) 3 rR Where: Q - volume flow rate, cu ft/sec R = pipe radius, in. P -- static pressure., psia L -- incremental pipe length, ft It includes these assumptions: 1. Isothermal, s t e a d y-s t a t e flow through a vertical pipe. 2. Rate of shear is proportional to the excess of the shear stress over a constant yield value, below which the material behaves as a continuous unit. 3. No slippage at the pipe wall. 4. Flow is laminar. The Buckingham-Reiner e q u at i o n was written for a fluid with constant density, plastic viscosity, and yield s t re s s throughout the flow length. However, vertical foam flow does not have constant rheological properties from one depth to the next. As an approximation to the Bucking- ham-Reiner model, the pipe and annu- lus are divided into' incremental l('nglhs ct O(lual, small p re s s u re changes, and the foam l)rOl)erlies arc assumed to be constant in each incre- mental length. In a foam-drilling operation, fluid temperature increases with depth. As an approximation to isothermal flow, the temperature in the annulus and pipe are assumed constant and equal to the adjacent formation temperature at each incremental depth. A surface temperature of 60° F. and a geother- mal gradient of 1.6° F./100 ft has been Table 1 What thc terms mean A--Annular flow area, sq ft A,---Pipe flow area, sq ft d--Di~'ferential calculus operator D,,~Outside pipe diameter, in. O,--Inside, annulus diameter, in. E--Slot lateral extent, in. 32.2 lb,,, ft g--Grav, constant Ibr/sq sec L--Incremental pipe length, ft M--Mass rate of flow, Ib,,,/sec n--Bingham plastic fluid power coefficient P--Static pressure head, psia p--Pressure, psia · ' Q--Volume flow rate, cu ft/sec R--Inside radius of pipe, in. r--Point of differentiation and integration V--Average velocity of flow, fps Vol ...... --Unit annulus volume Vol ..... ~--Unit rock volume Vol,,,.--Unit air volume Vol,,-~--Unit w~ter volume r--Specific weight, lbdcu It 'l'--Quality of fluid f.~,,--Dynamic plastic viscosity, cp Ib,,,-ft or--- sec 4,--Shear rate, .sec-~ p--Flowing density, Ib.,/cu ft r--Shear stress, psi or Ibdsq ft r,--Yield shear stress, psi or Ib,/sq ft r,~Shear stress at pipe wall SUBSCRIPTS a--Air i~lth iteration L~Pipe exit n--Total number of i.te.rations O~Pipe entrance r--Rock s~S'rP: 14.7 psia and 60° F. t~Total w--Water z~Depth of the midpoint of the L, iteration used to determine the formation tem- perature. No corrections were made for the expansion or compression of the air or the friction of flow. The ideal case of a circular hole with concentric drill pipe has been as- sumed and used for all computations. In practice, the uncased hole will not be circular, and the drill pipe will not be concentric with the hole. Since the severity of noncircularity and eccen- tricity differ for each hole, no correc- lions have I)e.(;n attempted for either. Mitclmll fotm(1 lhrough laboratory experinaents that foam slippage at the pipe wall did not exist, or was insig- nificant.~ Numerical integration. For flow down the drill pipe, a modified Buck- ingham-Reiner equation defines the flow of foam: ,~e (r>./r~t)'~ term in Equation 2 can be shown from experimental work to be small and therefore has been dropped. The static t)ressure head, P, is defined in terms of the t)ressure and density, P -- p + t,gL, and the shear stress at the pipe wall r}t, is R(Po--P~,)/2L. Both are substituted into Equation 3 and solved explicitly for the flow length: Po -- Pi, L -- (4) 8fy 8p, pV ~+.~ -- pg 3R R2 Equation 4 is a linear equation de- scribing the flow length in terms of pressure changes and the rheological properties of the fluid. In finite-differ- ence form the equation may describe the flow of foam in a vertical pipe. i=l i=l 8'fyi 8~piVi 3R Rz (5) Solutions of Equation 5 were ob- tained as follows: The pressure- dependent variables -- flowing density (p) yield stress (fy), and plastic vis- cosity (1'.,) -- were averaged for each pressure increment. A 5-psi pressure differential (P~,~ -- P0, was selected and the incremental pipe length was then calculated. An iteration process was continued until the sum of the in- cremental lengths (L0 equaled the length of the pipe. For flow up the annulus Melrose, et al.,4 have shown that the flow equa- tion for the Bingham plastic fluid in a concentric pipe-annulus arrangement can l)e closely al)l)roximated by tile cqu;~lion which dcscril)es fh)w through II ll~ll'l'()W sh)t. Their flow equation can be written as; EW'-' rw Q --~ × (6) rrR"(Po-P~) [1- 4 fy] (3) Q-- ~ 3 Ty 1 Ty 3 _ __ + -(-) ] 2 r~, 2 THE OIL AND GAS JOURNAI,--FEBI~,UARY 7, 1972 Air, water needs at minimum hydraulic hp Fig. 2 150- 3~ $o- -Pipe size:: 3.S0 in. I, i" Hole size ~ 7.87 in.' -Pipe size== 4.50 in.~ o I ~ 3 - 4 5 6 I 8 9 IO II 12 :. 0 I 2 3 4 s & ; 8 , ~0 11 1~ ~p~h, i,ooo ~ I!~ I I I I .... Hole size ~- 12.5 in, , ~ l --Pipe size=-: 5.$0 in. [ . ~ I ~-- v~ o'~,. i .,.-, ..,.-.,~- 7oo- 2,o~ ee --Pipe size: I $30 in. ~- °o 1 2 3 4 S 6 7 B 9 JO II : Following the same procedure as outlined for flow down the pipe, the annulus equation in terms of flow length is: L -- (7) 48V/% 6fy pg d d (Do -- D~)~ (Do' D0 Where: V -- average flow velocity, fps t, -- flowing density, lbm/CU ft Do -- pipe OD, in. D~ = annulus ID, in. The equation in finite-difference form is: ~ Li -- i=l i--1 PI,I ~ Pi p~g + 48Vi/~.pi 6fyi + (Do--DO (8) A similar procedure, which lead to the solution of flow down the pipe, was used. Itowever, in the annulus, rock particles are being lifted by the foam and adjustments are necessary. The flowing density, quality, and velocity must be adjusted for the mass and the volume of these rock cuttings. If a constant penetration rate is as- sumed, the density of foam and rock mixture in the annulus at a depth z will be: Where: Fig. 3 Circulating pressures 5,000 i4,000 3,000 2,000 1,000 0 1 2 3 4 5 6 7 8 9101112 Depth, 1,000 ft M = mass flow rate, lb,,/sec Q = volume flow rate, cu ft/sec M,.,. + Mr (9) and the velocity of the mixture is: (lO) Where: A -- annular flow area, sq ft Since the calculation of foam quality requires a knowledge of air and water volumes, a correction must be made for the rock-chip volumes in the an- nulus. A volume balance on a section of the annulus yields: Vol,~ + VOlw.,. + Vol,.,,,q¢ -- Vol ......(11) The annular volume for a unit length is: ~-(Do2 -- Vol ...... = (12) Assuming that rock-particles slip- page does nol: occur, then the rock volume fh)wing in a unit length of annular volume is Vol ..... , Qr Vol,,,,,,k -- --- Qt~, + Q,. (13) Substitution of Equations 12 and 13 into Equation 11 gives the air and rilE OIL AND GAS JOURNAL--FEBRUARY 7, 1972 63 w"ater vglumes in a unit length at tht annulus: Q.z Vol,,,,, Vol,,. "- (14) Q~ + Q~ The volume of the air at a depth z in the unit length of the annulus is: Q,z VOlann voL,. = (15) Qt~ + Q~ The quality at z is: Vol~z T,. -- (16) Vol,,,. -t- Volw,. Knowing the foam quality, it is possible to evaluate the yield stress and the plastic viscosity from Fig. 1. All of the variables in Equation 8 are now known, and the incremental flow length in the annulus may be calculated. Example problem. Air-volume rates,. water-volume rates, and injection pres- sures that minimize hydraulic horse- power have been determined in this NELSON COST INDEXES Refinery construction (1946 basis) Explained on Page 97 of the issue 1954 1960 1968 Pumps, compressors, etc ..... 166.5 228.3 284.4 Electrical machinery ........ 160.0 ~195.2 .198.2 Internal-comb. engines ...... 150.5 180.7 198.9 Instruments ............... 154.6 202.5 239.1 Heat exchangers ........... 171.7 194.0 223.4 Misc. equip, average ........ 160.7 200.0 228.8 Materials component ........ 174.6 207.6 224.1 Labor component ........... 183.3 241.9 357.4 Nelson Refinery (Inflation) Index .......... 179.8 228.2 304.1 Construction and Design Productivity ... 1.708 2.211 2.816 :~Nelson Construction (True Cost)Index ......... 105.3 103.2 108.0 of May 15, 1967 Sept., 1969 1970 1970 298.6 313.1 317.2 201.7 208.6 210.6 207.4 217.0 217.7 252.8 278.8 289.4 235.8 253.8 259.0 239.3 254.3 258.8 234.9 250.5 254.0 391.8 441.1 458.7 329.0 364.9 376.8 3.092 3.092 3.193 106.4 118.0 118.0 Aug., Sept., 1971 1971 332.8 332.8 215.4 215.0 228.4 228.6 309.7 309.7 270.4 270.4 271.3 271.5 267.9 267.9 514.4 517.0 415.8 517.4 3.524 3.537 118.0 118.0 Refinery operating (1956 basis) Explained on Page 161 of the issue of Apr. 6, 1964 Sept., Aug., Sept., 1954 1960 1968 1969 1970 1970 1971 1971 Fuel cost ................. 86.5 Labor cost .............. 90.9 WaRes ........... 88.7 P~oduclivity .. 97.1 I,vesl., mainl., otc... 92.0 Chemical costs ...... '.85.7 Nelson operating indexes Refinery .............. ... 88.7 Process units* . ......... 88.4 109.9 ]03.8 107.1 129.2 149.6 100.3 91.8 91.3 101.8 103.0 113.0 ]58.0 171.3 183.1 187.9 112.9 173.1 187.6 179.9 1.82.4 116.9 105.9 1104.3 f115.7 '1'115.7 114.3 124.3 125.9 127.4 132.4 167.0 167.0 104.2 108.3 194.2 199.4 186.4 184.2 '1]]5.7 1115.7 121.1 121.1 108.8 103.5 104.3 113.9 117.4 117.3 119.0 107.2 101.3 102.5 117.6 126.1 133.2 134.4 *Add separate index(es) for chemicals, if any are used. tRevised method which corrects for productivity and refinery complexity, l:For refineries actually built (increased capacity, increased complexity). See Quarterly Costimating, July 4, 1966, p. 110. These indexes are published in the first issue of each month. They are corn,piled by W. L. Nelson, Technical Editor and petroleum refinery consultant, Tulsa. Charts of the indexes are published each year in a late January issue. Indexes of selected individual items of equipment and materials are also published on the Costimating page in the first issue of .the months of January, April, July, and October. s. The results for common drill pipe and hole sizes are shown in Figs. 2 and 3. An annuh,s surface pressure of 14.7 psia (atmospheric) at a quality of 0.96, and an annular velocity at the bottom of the pipe of 90 fpm have been used as boundary conditions. In a practical application, air and water-volume rates are independent of drilling rate. However, as drilling rate increases, the surface injection pressure must be increased. As depth increases, all quantities must be increased according to the appropriate figure. If additional annular velocity--more than 90 fpm--is required to carry the cuttings from the hole, volume of air, water, and injection pressure must be increased. Air is the primary com- ponent affecting the velocity of the foam. If only air is increased, foam quality at the surface could be in the range in which it will turn to mist. If the mist region is entered, foam viscosity and yield stress drop dras- tically. Carrying capacity then de- pends on velocity of the air. Any departure from the specified minimum hydraulic horsepowers re- quires additional energy in order to maintain the boundary conditions..~ For instance, if higher injection pressure is used, annulus pres. sure must be increased above 14.7 psia. As a sample problem, assume the following operating conditions: 4½-in. OD drill pipe in a 77A-in. hole; a drill- ing depth of 4,500 ft; and a drilling rate of 0.5 pfs. Answers to this example can be read directly from Figs. 3 and 4: Water volume -- 122.0 gpm Air volume = 304.0 scfm Injection pressure -- 111.0 psia Bottom-hole circulating pressure -- 1,240 psia References I. Mitchell, B. J., "Viscosity of Foam," doctoral thesis, Univc,'sity of Oklahoma, .lanLu~l y 1970. 2. Itingham, I!. ('., "l"hiidily nmi I'hislic- ity," New Yo,'k, Mc(;raw-Ilill Ilook Co., 1922. 3. ('raft, B. C., Ih)hlcn, J. G., and Graves, F.. D., Jr., "Well l)csign," I'renlice-llall, lnc., l_;.nglewood Cliff, 1962, pp. 34-43. 4. Melrose, J. C., Savin, J. G., Foster, W. R., aral I'arJsh, E. it., "A I)ractical Utilization of the theory of Bingham Plastic Flow in Slalionary l'ipes and Annuli," Trans., AIME, 213, 19:58, pp. 316-24. 5. Krug, J. A., "Air and Water Volume Requircnmnts for Foam Drilling Opera- fions," MS thesis, Colorado School of Mines, l)cccmbcr 1971. 6. Wolhe, I(., private communication, Dresser Magcobar. 64 THE OIL AND GAS JOURNAL--FEBRUARY 7, 1972 COM?~RESSOR COMPRESSORS DISCHARGE / ./- L~N~' ~ ,.---% ~ VALVE I V CONNECTOR CHEC~VE~// ~ ~ CHEMICAL /~~ ~ j JPU~P WITH / ~ ~~SOLID3 INJECTOR ChECM VaLVE~ TO SHUT-IN STAND VALVE ~ _ _ _ PIPE 6 ~ ~ TO'MUD PUMP GENERALIZED s u r- face equipment hookup for air drill- ing under varying hole conditions. Fig. 1. Here is some of the equipment you'll need for effective air drilling THE HORSEPOWER needed to air drill a certain hole size at a given penetration rate in a given area under constant hole conditions can be plotted according to depth. Should this curve be used to find horsepower require- ments for some other area, the job might well be an economic failure. Maintaining a clean hole is the pri- mary duty of horsepower for air- drilling compressors. The amount of horsepower needed to clean the hole depends on many things. The first variable is hole size. Hole size varies in a well where a liner is hung. A soft section may erode while being .drilled and give hole enlarge- ment. The horsepower needed for hole size mtist satisfy the most demanding portion of the hole. A wet hole requires more horse- power Ihan a dry one. Foaming agents have rcch,ccd Ihis re¢lllircmenl; how- ever, Iht iuldili,)iml wciglil Io lift (nil el thc hole rcquil'eS more energy. I}cnclralion rale affccls lhc demand. As cultings are accumuhlIcd faslcr, Iheir total weighl increases and more energy is needed It) lift lhem. Deplh is a faclor in lhat friction increases with del, th :llld thc It}iai weight of millings in tile anntihls .iii- Cl'eascs. The cutting size, shape, and den- Author. is president, Technical l')rilling Services, Midland, "[ex. This article is a conclcrmalJon of a paper presented ;ti 1959 Petroleum Mechanical Conference of ASM E, Houston. sity affect the slippage of the cuttings in the air stream. Heavy, spherical cuttings are extremely difficult to lift. Friction losses in surface connec- tions consume horsepower. Small i.d. drill pipe and drill collars also con- sume horsepower. Jet bits or restricted bits use energy. A small flow line or restricted flow line uses horsepower. Those variables and many others make it almost impossible to plot an accurate curve for horsepower re- quirements for air or gas drilling. At best it would be a wide curve which would only give a minimum and a possible maximum. The maximum for any well would actually be determined by economics. Air inanifolds . . . Air manifolds and air lines should avoi(I undue rcstric- lions and have a safe working pres- s~ll'e. All h)w-l)rCss~irc CtltlilmlCnl sll()~ild Im prelected I~y a 1,51)1)])si. or higher check valve. Each comj}rcssor should bc pi'olcclcd by a valve or check valve for maintenance and lo facililalc chai}ging tinits, l-lamlncr unions speed inslalhdion and pre- vent (hlnmgc Io air Piping when being moved. I?ig. I is ;I roct)nlfnolldOd lay(uti, ~i'llc mud line should have a high- pressure valve between the mud pumps and the air opening lo prevent air from gelling into lhc pumps. Thc air opening in the mud linc should have a high-pressure valve to BY F. W. SMITH be closed when thc air compressors are down and mud drilli.ng is started. A valve is needed at the compressors to close for connections and other- wise control air flow. Additional equipment such as boosters, chemical pumps, injectors, etc., should be protected by valves and check valves. In aerated fluid a double check- valve arrangement is necessary to insure free, ~at'e passage of air to protect the equipment from any fluids or pressures from the rig. Gas nnmifolds . , . '['he gas supply ' line shotild be sized to deliver suffi- cient volume for drilling, with con- sideralion for increased demands for special problen~s. The working pres- sure shoultl he above the maximum j)rcsSlll'c' ()[' Iht 'l'lw n~;~i~l co~lrol valve sh(u~hl be Iocalc,d 15() II. from Iht rig. II sl}ould bc ~ainl;Jincd in pcrfccl working der and everyone on lhc rig should be familiar wilh ils location and opcr- alion in cvcnl of emcrgcncy. !1 should hc easily accessihlc. As i"ig. 2 shows, thc gas linc shotlld lic inlo II~e sl;indpipc on lhc rig 'l'hc.following connections arc from lhe gas supply lo thc standpipe, all of which should he easily observed and controlled on thc floor: A pres- sure gage for Iht gas-supply linc; a valve Io bc uscd for conncclions and OCTOBER 26, 1959--VOL. 57, NO. 44 83 , , SWIV(~ ROTARY~ ao,^a¥~ u u DRILL STABILIZERS OR REAMI ORILL COLLARS otherwise control the gas supply; a choke to regulate the volume of gas; a check valve to prohibit any fluids from being pumped up the gas line; a pressure gage for drilling pressure. A flow meter between the check valve and control valve is recommended but not necessary. Size, weight of compressors . . . Nu- merous factors regulate the size and weight of compressors to be used in air drilling. The variations~ in state regulations lead to confusion in sizing equipment and practically eliminate any type of ~tandardization. The com- pressor~ mtl~t be sized so that equip- menl can be moved ¢)n highwnys. Easy hamlling and mobility on loca- tion is necessary. Generally the com- pressors arc sized lo list: ['1'O111 150 lo 350 hp. to satisfy most limilalitms. When compressors are sized too large in individual units, malfunction in one compressor could shut down the entire air operations until repairs or replacements could bc made. Air drilling may be continued with no loss of time by using smaller units in greater number. One small compressor clown may not affect drilling condi- tions for several hours. Horsepower requirements are an ~ ROTATING I PACI~OFF ~ CHOKE BLOWOUT / ~ 3 I~.) PREVENTER WITH BLIND L RAMS OR MASTER VALVE ~~ P_k FILLUP LINE v..w~ ~ ~ o~ STANDARD ASSEMBLY for two blowout preventers, 3,000- psi. working pressure, 6,000-psi. test. When drilling, use drill-pipe rams for top preventer and blind rams or master valve for bottom preventer. Fig. 3. RIO and downhole assembly equip- ment {:or oir or gas drilling. Fig. 2. essential element in economical air drilling. Penetration rates, volume, pressure, and well conditions depend on available horsepower. Insufficient horsepower results in more rig down time. To determine amount of horse- power required, size and depth of hole, volume and pressures antici- pated, types of formation and size of drill string should be taken into con- sideration. The horsepower of com- pressor equipment could vary from 50 to as much as 1,500 hp. Pressure and temperature . . . Low- pressure compressors of 125 psi. or less arc nol tisually sufficient for air drilling. I iighcr i~i'cssu,'c conlprcssors arc needed. A working pressure of 150 lo 500 psi. is desired in most air- drilled wells. In mist, slug, or aerated fluid drilling, high-si:igc compressor or boosters capable of 1,500 psi. arc required. Compressing air from atmospheric pressure lo air-drilling pressures de- velops high Icmj)cralLIrcs. All air compressors used in air drilling should have intcrcoolers and aflercoolcrs and aulonmtic unloaders. Thc unloaders should hc scl al 10 psi. above maximum compressor working pressure and checked frequently. Maximum temperature for safe air drilling is 150° F. Lower tempera- tures are desirable. Condensation to some extent is present in all air compressors. Each compressor should be equipped with a scrubber or knockout bottle, in order to break out and drain fluids from the air system. In humid sum- mer weather the condensation be- comes greater and requires .frequent drainage of fluids. When condensa- tion is not controlled during dry drilling, enough moisture could reach the formation to cause the cuttings to bali up. Wellhead equipment . . . The well- head equipment required for air or gas drilling depends on hole depth, size, and anticipated pressures. Two types of wellhead hookups are recom- mended with variations. 1. Low pressure well hookup. The accepted wellhead assembly for Iow- pressure areas is a 3,000-psi. working pressure (see Fig. 3). 2. in high-pressure areas, the copied wellhead is a 5,000-psi. pres- stlre (sec I:ig. 4). 'l'l~csc wclll~cad asscml)lics have been proven salisfaclory in practice at,ti should mccl all emergency comli.. tit)lis when JBail~l;Lincd in i~ormal working order. All blowoul preventers should be equipped with closing mani- fold opcraled by hydraulic oil in a closed fluid system. 'l'he flow linc should have an iii- ternal area as large or larger than thc area of Ihe annulus. The minimum length of l'low line should be 150 fl. The fh)w linc should be securely anchored. The drill string used in air or gas THE OIL AND GAS JOURNAL ROTATING STRIPPER HEAD FILLUP LINE' 6 IN. VALVE MINIMUM SIZE 7 IN. BLOW LINE B.O.P. 5,000 PSI. MAXIMUM ,HUT-IN PRESSURE EMERGENCY KILL LINE CHECK VALVE 4 IN. VALVES B.O.PWITH PIPE 5,000 PSI. MAXIMUM SHUT-IN PRESSURE B.O.P. WITH BLIND RAMS 5,000 PSI. SHUT-IN PRESSURE EMERGENCY KILL LINE' 6 IN. VALVE . CROSS BEYOND EDGE L-,~. [ OF DERRICK KE MANIFOLD FLOOR I~ TOP CELLAR WALL CHECK VALVE RECOMMENDED blowout - preventer hookup for air-gas- mist drilling, 5,000- psi. working pres- sure. Fig. 4. drilling is the same as would be used in good drilling practices with fluid. Some consideration should be given to the additional weight involved, as air or gas gives no flotation. Drill pipe . . . The drill pipe should have tapered tool joints or bottle- neck pipe to avoid undue wear on the rotating head rubber. Drill-pipe rubbers are not recommended as they are pulled loose by the stripper rub- ber. The drill pipe should be as large as practical to reduce internal fric- tion and annulus area. This reduces the horsepower needed to clean the hole. Drill collars . . . The drill collars sh()llhl I)c as large as praclic;ll for slal)ilizalion. Em)ugh collars ~hould be used to apply maximum bit weights. A float is essential and should be inspected each trip. Metallic-type Ihread dope is best for drill collar and pipe. Reamers, stabilizers . . . In areas of crooke,I hole, the "packed hole" prin- ciple ms rccomnlendcd. Generally a diamond or roller-type rc'an~cr is run above the bit and a boot-lypc stabilizer or a reamer 30 ft. up. Should hole continue to deviate to maximum limits, the pendulum effect may be used to control inclination from vertical. Bits . . . Bits used in air or gas drill- ing are of the hard formation type. The smaller, harder teeth and larger bearings give longer bit life with no sacrifice in penetration rate. These bits are used in the soft to medium- hard formations. The tungsten carbide insert-type bit is generally used in hard formations and in deeper wells. The insert-type bit gives faster pene- tration rates, longer bit life and more gage protection. llanlmerdrili . . . Thc hammerdrill is used in n~edium-hard to hard forma- lions. Il comlfincs ibc percussion and rotary mclhods of drilli~g. 'i'l~c is run tlircclly al)ovc Iht Ifil. this Iool is rtlll, air or gas and volume are increased. The addi- tional pressure is required to operate the hammer, and additional volume is needed to clean lhe hole, as pene- Iralion is faster and cultis~gs arc l,rge. Surface equipinent . . . The surface equipment should be selected with care. A straight kelly is csscntial and a hexagonal kelly is prcfcrahle. In gas drilling, the rotary hose may bc damaged by deterioration from hy- drocarbons, making it necessary to use an all-purpose steel rotary hose. Instrumentation . . . The drill-time record is thc first indication of a different formation. This instrument is widely accepted and is important for drilling evahiation in air and gas drilling. The torque gage is important in determining a dull or out-of-gage bit, or a hole that is not being cleaned. The weight indicator must be sensi- tive where light weights are run, as in crooked hole. A Iow-pressure gage is necessary on the stand pipe as pressure range in the low hundreds rather than in the lhousands. in gas drilling a flow-line meter is necessary to determine volume. A Icmpcralure gage on the flow linc gives indic;ilion of a wet zone; howcvcr, Ihe ccss;ilitm (,1' tltisl is ~lstlally s~ll'licicnl I0 imlicalc this con- dition. inlcrstagc prcsst~rc gages arc tiscd on lhe compressors lo determine w~lvc mall'~lnclions. A tcmper;dure gage will also imlicalc a ix,I w~lvc. ()lber l,;qimilmlenl 'ibc c, qlliprncnl tisctl wilh choral- calx ill fill' filial gils drilling is varied in al~j~licalion. 15c{~lipmcl~l is Beetled for SClUCCZing walcr zollcs, mist drill- ing, and solid injection of dry chemi- cals. Water shutoff involves equipment generally used in squeeze operations. Logging equipment is sometimes used in squeeze operations to pick the zone of water entry. Packers are used to isolate the zone. Pumps or high- pressure gas is used for the squeeze. When cement, plastics, or gels are used, the techniques and equipment are much the same as a normal squeeze with special mixing equipment . necessary in some cases. With a water- sensitive gas, either a pump and pumP- down plug or high-pressure gas is used as a flush and little other equip- ment is necessary. Foaming agent is injected with a small fluid pump. The pump should have a range of from 2 to 20 bbl. of fluid per hour. A connected steam pump or an air-operated pump is normally used. The pump should have a 500-psi. working pressure or more. A mixing tank to blend the chemicals with water should be mounted near the pump, preferably On the same skid. This tank should be from 5 to 20-bbl. capacity. The pump is mani- folded into the gas stream as shown in Fig. 1. The solids injector is used to inject powders 'for controlling weak water zones or to adjust a powder to reduce torque in deeper wells. The most prac- tical machine used is an endless belt with pistons to inject the powders in a constant-measured amount. This machine is shown tied into the air or gas line in Fig. 1. In some areas where the humiditv is continuously high, an inline scrul~- her is necessary with air compressors to insure that air is dry as possible. This scrubber must be of sufficient .working pressure and large enough to handle the volume. The scrubber .is hooked into the air line near the well to allow the air to cool. A wellhead testing tool is now avail- able to allow testing of all blowout equipment with fluid pressure. With this tool only a minimum amount of water is lost into the hole. After sev- eral days of dry drilling, the tool should be used to determine whether any flanges or connections have worked loose. ()n many wihlcal wells, this proccdtlrc is used al prctlclcr- mined intcrwtls. An automatic driller can mean extra footage in most cases, it is par- ticularly important when light weights tire being run. Deepening anti Cleanout A direct descendant of air and mist drilling is air cleanout and deepening. This method is often the quickest and most effective procedure in remedial work. Equipment requirements for air cleanout and deepening are similar to mist-drilling practices. Compressor requirements · ·. Normal working pressures will vary from 350 to 500 psi. Compressors should be equipped with intercoolers and after- coolers for minimum temperatures. Maximum temperature for air clean- out is 125° F: Volume normally is from 2-3 M.c.f.m. governed by well conditions. Manifold, accessory equip~nent . · · The air manifold and air line should follow the outline used for normal mist drilling. The booster should be located between the compressors and the chemical pump. Connections and valves of 1.500 psi. are re- quired' for booster and chemical pumP. The chemical pump should be connected into the air line between all compressors and the rig. The chem- ical pump should have a shutoff valve and check valve of 1,500 psi. A mixing tank is needed to get the cor- rect mixture of chemicals and give an accurate measurement of fluids in- jected into the air stream. The chem- ical pump should be controlled to reach desired injection rate. Sec Fig. I. Rig requirements . · · The size and type rig used in air cleanout and deepening depends on depth of hole and weight of the drill string. The rig should be a rotary-type rig or equipped with rotary attach- ment. Power swivels are recom- mended in air cleanout and deepen- ing. The drill string will usually con- sist of the production tubing. The tubing 'should be in good condition and checked for holes and damaged joints. When production string of tubing is used, a torque gage should be used on rotary equipment to pre- vent damage to tubing. The drill string should contain a float sub above the jet sub in air cleanout. A float is essential at all times in air cleanout and deepening. A jet sub is recommended for air cleanout. Bits, collars . · . in clcanout opera- lions lilt: Ifil is t~scd very lilllc lo drill and requires no specific design..l Iow- over, the waler courses should be full opening to accommodate greater vol- umes of air. In air-and-gas deepening, it is rec- ommended lhat at leasl 60 fl. or more drill collars be used for stabilization and weight. The sizing of lhe drill collars depends upon the hole size and annulus clearances. A float should be installed in the bottom drill collar just above the bit. Wellhead equipment . · · The well- head equipment used in air cleanout and deepening should be as compact and small as possible due to limited and crowded working area. When blowout preventors are desired, it is recommended that they be installed on the well casing as near ground level as possible. A bleedoff line be- low the blowout prcvcntor is neces- sary. The flow nipple should be in- stalled above Iht blowout prevcntor with fhmges. A rubber-insert-type packoff head is recommended. The packoff head should remain as simple and small as possible. The flow linc should be 6 in. or more in diameter. Lightweight casing or thinwall steel pipe of 500 psi. or more working pressure is used. The flow line should be anchored near the discharge end. In air cleanout and deepening, it is recommcndcd a steel pit be used. This will allow recovery of all oil pro- duced during well operations. It will eliminate thc possibilities of spraying the location and surrounding area with discharged fluids. Thc sleel pit is easily mowtble and requires very little rigup and rigdown time. Proldems and Future Equipment There have been some difficulties with small rotary tables. The table must be large enough to allow pas- sage of the rotating head. Substructures are generally too low to accommodate all the blowout pre- ventors and the rotating head. It is often necessary to raise them to have part of the preventor equipment in the cellar. Compressor weight is an important consideration in transporta- tion. Drill-string strength is a prob- lem in deeper wells. In some cases, thc drill pipe is the limiting factor for the depth that airor gas may be used. The advent of the Hammerdrill has thrown open the door for new bit designs. Several thousand feet per bit may be expected. A top-hole float will be built that will allow slope tests without undue loss of time. A shorter rotating head is expected. This will be prclubricated and rela- tively nminfcnance [rec, A now-type I~hm'out IIt~oktll~ nlalcing tile wcllllcad cquilm~Cnl shorlcr, more coln[~;icl, and easier to install is desired. An efficient separator lo clean Iht dust and cullings from gas so tim gas can be relurncd Io lhc pipeline is needed. New chemicals and chemical injectors will be aw~ilable for walcr proble~¥s lbus crealing numcrot,s new areas for air and gas. A botlom-hole recording gage Io obtain pressure and tcrnpcrature at the bil, both inside and outside, woukl. give more engineering information on future tool designs. · p~o u Preprinted from October 1974 A GULF PUBLISHING COMPANY PUBLICATION P. O. Box 2608 Houston, Texas U.S.A. 77001 COPYRIGHT© 1974 By Gulf Publishing Co. All Rights Reserved l'riutt'd ilx What to consider when selecting drilling fluids What to consider when selecting drilling fluids S. O. Hutchison, Staff Engineer, and G. W. Anderson, Technolog'y Development, Producing' l)el):::'tn~(:nt, ,Stal:tla:'(l Oil Co. of California, Western Operations, Inc., Oil(lalc, I O-second summary Sclecting proper drilling fluids is very frei)arrant for no~nic drilling of wells, for oncc a location is sch,ctcd and drilling equipmcnt is rigged up, care and usc of thc drilling Iluid arc thc most important factors the operator can conlr~l. 5lajor points to consider when choosing a circulating mccli:lm includ(: formation gcology, formation prcssurc, gcothcrnml tt'ml)cratur(:, mal~c-u1) water availability and quality, penetration ]'alcs, formation eval- uation, completion proccdurcs and ecoh)gical consid('rati()ns. SIGNII:ICANT ADVANCES havc beCll l/iii(t{; (tt~vin~- thc t)::st in developing new drilling fluids, and solids and kick control mcnt. And understanding of th(; rclationsl:i1) botxv'co~] bore hr)lc stability and various types of drilling /lt~irl,s hax iml)rO¥c(l. Other rcccnt developments includc low density drillin,g' Nui(ts for fast penetration rates .and improved formation {:valuation. But mud must be tailored to each individual al)l>lication and cquipmcnt should bc provided before tl~c well is Thc following articles discuss: v-- Types of drilling fluids available How d,rilling fluid properties aft;cot x'a:'iot:x drilli]:g v:~:'i:tblcs Equipment needed to evaluate and mai:~tain (l:'illi]~g lluids. Most information is prescutcd in tabular form fo:' case of :'cfc:'- cncc. Some additional explanatory mal¢'rial ix i~{;l~rt~'rt ¢)~ u,sc of recently introduced stable foam circulating' tltlicts, bcclltlse of the general lack of such data in thc publish, cd lit(:raturc. Each drilling fluid has specific application A wide range of drilling fluids is available. Here's ,a summary of some capabilities, costs and limitations Tm:m: ^~E Two main typcs of drilling fiuid systcms-- weighted and nonweighted, bttt therc are many diffcrcnt classes, ran~ing ~ro~n plain water to cxotic chemical solu- tions. To determine what type of fluid to usc, tim engi- neer must first understand what each was designed to accomplish. Drill/nE fluid density The wide range of circulating fluid cle~:sities now avail- able is illustrated in Fig.-1.1)ue to overlaI) of various fluid types, there is a considerable area of choice. Of l)arficular in]crest is the Iow cnd of the dcnsity scale, consisting of fluids such as air, mist, stable foam and aeratcd mud used in balanced or xinderbalanccd drilling. SOLIDS FREE FLUIDS These fluids theoretically can ])c selected ra~:ging in density from 0 to 12 ppg (0 to 90 pcf). llowcvcr, once drilling hegiras, tl~]itls ~n~st ~t~ttr;~izt solids. 'l']~t]s a(lctlL]atc s<)lids rc]~t,val provided ami used il~nxcdiatcly fine, vcgrol~nrl, fon~u~ti{)n s~ditls i~ t}~,' systc~. If arc not ten,ox'cd 1)v at]ctlttatc method of controllin,,' ~ndcsiraldc lniildt~t~ is l~x' ~lilt~tion storage a~td dispos:xl Air and 1)rcforn)cd slal)lc drilling fluids, q'hcy initially contain no s~dids a~d drilh'd formation solids entrai]~cd in rct~rns arc disc]~ar~cd di- rectly to a waste stlnlp. E{lL]ivalcnt circ~latiz~ (]cz~sitics from about 0.5 T~){~ (3.75 pcf) to ,).., i)i>~ (7() l)Cf) can be practically acl~icvcd will) l>ri, ft>r]]u'd slal)h, t'()al~: llt~ids where approl)riate back In'CSSt~rc and rt)kati~ ]Jo:rd t>ack- off equipment is used, since liftin~ ability of t'<)a~ del)ends ~0.0 ~ -- 10'4 Il ~ M50~' . FLUID DENSITY Fig. 1--Theoretically, drilling fluids can be formulated wilh densities ranging from 0 ppg (or pcf) to 20 ppg (150 pcf) using a variety of basic fluids and fluid additives. Various fluids overlap on the density scale, thus providin9 for a wide range of drilling fluid choices. How fluid properties affect drilling variables Different circulating fluids have widely varying effects on penetration rates, hole cleaning, hole stability and formation evaluation I)RILLING FLUIDS sh,ould be selected based on anticipated conditions that will be encountered while drilling. Within a given class, drilling fluids may have drastically different effects on drilling rates, hole stability and formation evaluation. Curves in Fig. 2 compare the effect of individual mud properties on penetration rate. Density and solids content are the most severe rate reducers and are inter-dependent. Density should be kept as close to formation pressure gradient as practical, and solids should be controlled in the optimum range. Viscosity is significant and should be maintained as close to water viscosity as possible for maximum drilling rates. Oil in mud can be beneticial in some instauces-- with about 5 to 7% being the optimum range. Higher fluid losses show slightly increased drilling rates, but hole stability can be a limiting factor. In drilling op- erations, mud properties are all inter-dependent to some degree and all must 'be considered in designing an opti- mum di'illing rate mud system. Shear thinning effects · As mentioned previously, Ol, timum viscosity for maxi- mum drilling rates is at, or near, tile viscosity of water. But a higher viscosity in the annulus is desirable for maxi- mum solids transport efficiency. A shear thinning type fluid, Fig. 3, approaches' both these criteria--very tow viscosity under ultra high shear rates through the bit nozzles and increased viscosity in tile annulus for better ho'le cleaning. Thc only disadvantage to this fluid is high viscosity in the low shear rate area of the mud pits, which prevents solids settling. However, this effect can be overcome easily .by using mechanical solids removal equipment such as desanders, desilters and cen- trifuges for more efficient solids control. Continued on fo/lowing page INCREASING' Fig. 2--With the exception of water loss, increasing drilling fluid properties cause a decline in drilling rat'e. Solids content and density, which are inter-dependent, have the most detri- mental effect on drilling rates. (After Moore). 1000 100 10 CLAY WAT 10 100 1000 10,~00 100,000 SHEAR RATE Fig. 3--Shear thinning effects of a drilling fluid are important to the economics of drilling. While one fluid may exhibit the right properties at high shear rates, it may be unsatisfactory at Iow shear rates. (After Kennedy and Meyer). ~ 60 40 0 I L 100 200 300 400 500 TEMPERATURE Fig. 4--Temperature affects drilling· fluid properties differently for different muds. Water base muds are most affected by tem- perature, while oil base muds are least affected. Foam systems may be used in a wide range of temperatures because of Iow heat capacity. (After McMordie). Temperature effects Extremely high bottom hole temperatures encountered in ultra deep and geothermal drilling makes temperature stability of a mud system an important factor. Water base nmds are useful to about 250°F before requiring excessive thinners at high cost to maintain desirable flow properties. A high concentration lignite mud appears to have the best high temperature properties, Fig. 4. Invert type oil muds are useful to over 400°F before costly maintenance ,becomes a factor. Low-water content oil base niuds h;t~c tim best higl~ tC~nl)eraturc stal)ility known to date. Preformed stal)le fo:un is an effective circulating fluid in 'both low (l)Cr~mt'rost) and high (geother~,:d) tem- perature areas due to its low specific heat capacity. Itigh temperature applications are limited by the inability of rubber pack-off material in BOP equitmwnt to hold pres- sure above 350°F and l)rCscnt :tvail:,bh¢ foaming agents chemically decompose at abrupt 4.70°F. Wet oxygen corro- sion also limits l~refornmd sta'bh~ f~ams usefulness above 350°F when air is used as tlm gaseous phase. Hole cleaning Hole cleaning ability' of a drilling tluid systc~ (see table) is det)emlc~t on viscosity and annular velocity. Annular velocity att:tinal)le d~qmntls o~ h(fi<¢ size and pump capacity, and these factm~ can l)ecmne critical in large diameter ho]es. Incre~ing drilling fluid viscosity may improve ho'lc cleaning, ,but penetration rates will be reduced and I~t circulation may result due to higher ammlar circulation pressures. Sta'ble foam drilling fluids are ideal for large diameter hole drilling since foam bas a very l~igh 'aplmrcnt viscosity with a very low l)otto~ h.ole circ~lating' (hmsity and will transport cuttings at very Iow velocity. Effective hole cleaning with air rmluires annular veloci- ties of 3,000 fpm or n~ore. These velocities are attainable in small to medium size holes, but in large diameter holes the air volume rC(luire~wnt l)econws lo~) CXlmnsive to consider. In unconsolidated formations, hole erosion caused by high annular velocities req~ircd for efficient cleaning with ai~ ..... may be excessive and will cmnl)ound cleaning problems. The excellent lifting ability of preformed stable foam (Fig. 5) is dependent upon foam stability as wt'll as liquid volume fraction (I.VF) and velocity. The stable foam region ranges from I,VF of about 0.02 to 0.25. Below a LVI: of 0.02, foan~ becomes intermittent Hole cleaning capabilities ' / Viscosity, Hole size, Annular Volume, type of Fluid Funnel Inches Velocity, fpm gpm Problem __ Water::.'. .............. i 28 97/~ . ·"120 400 Good cleaning in nominal size holes · 17J~ 45 500' Annular velocity too lmv, requires regrind!n~ · · · of cuttings for cleaning, slowing penetrat~o~ Clay-Mud...: ......... 40 97/{ 100 320 Good cleaning w/normal viscosity · ' 100 17.-.~ 40 500* Fair cleaning w/high viscosity, but result~ · in poor drilling rate and possil)le loss of cir culation Stable foam ........... Thick 9~ 75 300 cfm Excellent cleaning regardless of hole size · Stable 20 gpm Foam · . 173~ 40 300 cfm Adequate hole cleaning. Increasing annulal · ~ ' 20 gpm returnvel°citYti,neimpr°ves lifting ability and reduce~ · Air or' mist...:.. ....... -' 93~ 4,000 '1,650 cfm Adequate clea,fing-medium to Ibm dust cut tings 17~ 3,000 4,500 cfm Air voh.lme to maintain lifting velocity · .... ' large holes requires enormous volume of air . ~ expensive I , , * Maximum output of medium size rig pump Drilling flu~,l classification Cost Density pll Temp. per bbl, . ranlle* range limit, °F unweil4hted Uses and lin~itations .... . 1. Water base muds A. Water--fresh salts (NaCI, KCL, CaCl2) 62.4-00 pcf 7.0-8.0 210 0 -820 Bt:st ~h'lg. fluid if formations wil stand u p --lloccu lan ts help sctt solids B. Clay water, Formation solids fresh or salt Bentonite 0~86 . pcf 7.~8.0 200 $1-$8 Good for lop hole drilling, wil Native clays 8.7-11.5 ppg not tolerate contaminants-- cement, salts, etc. C. Calcium base Ca OH 6~145' pcf (;oo{l viscosity conlrol, not gooc Gypsum surfactant 8.7-19.5 ppg 11.0-12.0 275 $3-$.1 in acid slmlcs, solidifies abov{ 275~ 1: D. Dispersed clay Phosphates 65-145' pcf 7.5-8.0 200 $2 $5 I'hosl)ha/es & tan~i~s good nmd Tannins 8.7-19.5 ppg .).,.-10. o depth thimmrs, ]i~m>sulfonates. Lignites O.&10.0 450 lignites excellent, in hi-wt. LignoSulfonates 9.0-10,0 providing good lc~l), sial). ...... . E. Non dispersed Polyniers 6,~14S* pcf 7.0-9.0 250 $2--$h I.ow s~li{Is I~u~ls I~r¢~vide excel low solidsor Asbestos 8.7-19.5 ppg hint i)enclr;tli{m r,llcs, rCrluir~ optimum solids Extenders mech. solids contrL Surfactants 't50 mu(Is have excellent temp. stab .................... . LOil base muds Oil 51-61 pcf {lse in shallow hole drlg., vise 6.8-8.1 ppg 150 '$2-$8 drops w/temp. Treated crude~2-20% water plus 38-70* pcf "Poor Boy". ~il I)asc, shallow emulsifier 7.75-9.36 ppg 200 $3- $5 drlg. w/llloro {h.,asii y .............................. Invert emulsion~20-7fi% water + 58-1,t5' pcf .100 $!}--$12 I,ow viscosity Ihlhl flow maint emulsifier + oil-wetclays 7,75-19.5 ppg o,ts, cxcclhmt s}l;tlt, control iligh water content permit: limitc(l density ira:teases w/dis. solved salts . ..... Oil bas~2-20% water + emulsifier 58-140' pcf 500 $10~-$15 Excellent dcel) drlg. Ilulrl, cellcnt ICml). stalk low maint + asphalts 7.75'18.7 ppg costs ............. ~ t. Stable foam AEC stiff foam (Atomic Energy Comm.) [ 4-6 pcf 7.0-8.0 250 $2.50.-$8.50 Good penetration tales, excel gel-mud + foaming surfactant i 0.56-0.8 ~ ppg lent large hole cleaning, i wall building. Can hamllc : vol. walcr, will not tolerate water or Preformed stable foam (SOCAL) 34 pcf 4.0-10.0 400 $0.25-$a Excellent penctrati(m rates water + foaming surfactant + additives 0.4-0.8 ppg large hole clcauing. Can hamlh ' large vol~lmCS of water, Iow nular velocity, excelle~/ insula. tion to heat or cold. Can tolerat~ contaminants~-oil, salt, calciun ~ solids, sci(l, solvents, etc. [. Mist Mud + foaming surfac~nt 1-O pcf 7.0-11.0 300 $1.50~$2.50 Good wall l)uil(ling & nloderat~ water vol. l-ligh ammk~r veloc. ity, high air vol. requirement Foaming surfactant + water 0.13-0.8 ppg 350 $0.~,>. $- (Tan hantlh~ motleratc water x'~)l RCqLfi]'cs high air vol. w/big] , ann. velocity. ...................................................................................... i. Air or ~as ~ 0 ~00 Excellent penetrati~m in dr5 ~ , competent formations .... will { ~ tolerate ;vater-dust problems. ..... * With weighting materials WEIGHTED MUD SYSTEMS In ;yell planned drilling fiuid programs, weighted drilling' fluid needs should be anticipated and undesirable solids should be controlled at optimum levels to permit addition of weighting materials witl:out excessive dilution. Cost of building and n~aintai~ing wcigl~tcd ~t~(Is is ~nost significant~weight material ah>nc, r)vcr a.nd above mt:d cost, can range from al)out $5 lwr barrel in a 10.G ppg pcf) 'mud, up to $130 per bat',,., m maximum weig!,t systems. Drillin fluids c/assif/ca z'ion Drilling fluids can 'be divided into five basic types: water base, oil base, stable foam, mist and air (see table), and each type may have several sub-classifications. Cost figures shown are relative and are for unweighted fluids. WATER BASE FLUIDS Water is the simplest and one of the best drilling flnids if formations being drilled are competent and not sensitive to water wetting. Using small percentages of flocculants can greatly enhance water drilling by preventing drilled solids buildup.' Salt water has excellent applications when higher den- sity and formation clay inhibition is desirable. H'owever, they can be very expensive in areas where local natural sources.are not readily available. Cautio,z: Calcium and sodium chloride solutions can cause undesirable stable emulsions in certain crude oils. A simple test to determine emulsions stability is to mix 30 ml of crude oil and 10 ml of salt solution to be used. Observe time required for oil and water to separate. If separation is incomplete within 16 hours, then emulsion-breaking chemicals should be added to the salt solution and retcsted to determine pro- per chemicals and concentrations required. Clay water muds, the oldest form of drilling mud, con- sist of water with solids added for increased viscosity and density. Solids type is important--bentonitic solids are beneficial for viscosity and fluid loss control, but drilled solids or native clays, unless controlled, can be detrimental and result in too much viscosity and density. Calcium muds were popular several years ago and per- formed very well in certain types of shale drilling, l Iow- ever, they tend to solidify above 275° 1" and have lost favor in today's deep drilling. Dispersed muds probably are still the most commonly used drilling fluids. But as solids build up in a clay mud systmn, some type of dispcrsant or thinner must be used to control mud flow properties. In medium depth, normal temperature wells, polyphosphate, tannins and solubilized lignites,' are satisfactory, inexpensive thinners. However, at greater depths (higher bottom hole temperatures and higher densities), stronger dispersants are required--such as solubilized lignites and lignosulfonates--to maintain desirable flow properties. Non-dispersed drilling fluids are gaining popularity in deeper, highly competitive drilling. These fluids depend upon solids control for their excellent flow properties, but they can be low density-low solids or high density- optimum solids systems. Their low dispersion level tends to increase hole stability and make mechanical solids control equipment much more effective. ~[ost of these fluids also have a shear-thinning effect with low viscosity under the high shear rate at the bit, and higher viscosity in the annulus under iow shear rates for excellent pene- tration rates and hole cleaning. OIL BASE FLUIDS Crude oil can be used as a drilling fluid in shallow development drilling. However, oil with enough viscosity to carry solids ~a~:. . ,se its visct~sity raj)idly wlw~ exposed to increased temperat~res. Cad, tie,: ],ive crude oil or crude oil containing entrained gas can i)resent a high fire hazard. Treated crude, or "l'oor-Boy" oil base, is crude oil chemically emulsified with a small volmnc of water to stabilize viscosity. A limited a~n{n~t of tinely grmmd limestone is used for s~nall incremental increases in density. Treated crude uses are practical in a density range of 8.0-9.1 pp.~ (60 to 68 pcf). If greater densities are re- quired, oil base or invert emulsion muds should be used. Invert enmlsion muds are oil base muds containing 20 to 75~ salt water and powerftd e~n~llsilh'tm. The~e relatively Iow viscosity m~ds are easily controlled and exhibit excellent shale stabilizing properties. By balancing salinity, of the internal water phase with salinity, of fo~a- tion water, significant shale stability improvements can be realized. ()il base znmts m~r~allv c~tai~ Ir'ss water tln~z~ invert muds (2-20~) and gem~rally h:we }~igl~cr viscosities with excellent temperature stability for deep, h~)t holes. Both types of oil base ~nuds ~enorally have hi~l~, 'i~itial, per barrel costs, but normally have x low mainte~mnce cost. STABLE FOAM AEC type fo:un (dcvelotwd lw tim .\t,~,ic Energy Comnfissiou), frcq~e~tly referred to as "still"' f{~an~, con- sists of a g('l-l)ase n~t~d c()~ltaini~? c()~palil~lc foa)ning surfactant. When tiffs th~id is inj(.(:tcd into ;t~t air stream, the very viscous foam fornwd )u~s cxcelh,~t hole cleaning and wall building characteristics, llowever, calci~tm, salt water or crude oil contaminati{,~ can~{~t ])e tolerated. Bentonitcs tend to ball up in t}w l)rescn¢'c ¢~f salt water or caMum, a::ct foa~n(-rs cOn~l>atil>l(: wit]~ ]~(.~ti(mitc solids are not usually comI>atil)le with crude oil. Pre-formed stable foam is formed by inje(:tin~ a solu- tion of water (fresh ()r salt) 1)lt~s a fo;t)~in:: st~rfa<'tant into a gaseotls please in a f();t:n g(,mralor, l;y l)rcforming stable foa:n on tim surface and tht't~ circ~lating tlm foan~ down the hole, more contamination from calcium, solids, salt waters and crude oils can be tolerated. This foam has excellent hole clc;t::ing' ability ;tt v(,ry low annuh~ar velocity and has desirable tlwrmal In'Ol}crti<~s for t}erma- frost and high temperature operations. MIST A process where small volmnes of nmd or water, in- cluding a foaming surfactaut, is injected into a high ve- locity gaseous SIl'ealll fei'fils a mist drilling tluid. Its lmr- pose is to carry the fo:u~fing s~lrfactant in t]~c gaseous stream to the bottoln of tim hole wlmrc it )~dxcs with formation water to increase lift cfHdency of the high velocity gaseous stream aud to permit rcx~r)val of water from the hole. AIR Gas or air is an excellent drilling' tlt~id for dry compe- tent formations. Ilowevcr, since lift ability of air is dc- pendent upon annular velocity, air vohtnm requirements become prohibitive as hole size increases. I,iftinlr of AEC and performed stabh' fOillU del)ends uI~Ot~ viscosity a~d velocity of thc liqt~id-g'aseous mixture, w}~ile mist and air depend solely on tim velocity in the annulus. 1ti Evaluati ng and maintaining drilling fluid properties Here's a look at test equipment and rig components for proper use of diflerent types of drilling fluids IF A PARTICULAR drilling fluid's full benefits are to be realized, it must be maintained within certain limits. To determine whether mud properties are within these limits, proper testing equipment must be available. Then, to maintain these lixnits, adequate equipment should be on location 'for controlling density, viscosity, solids con- tent, etc. Another. consideration to be evaluated when selecting a drilling fluid is the ease with which the fluid can be disposed. Certain fluids require more expensive disposal techniques while not providing any substantially better benefits than a fluid which can be disposed of easily. / Fluid testing equipment Equipment required/or testing various types of drilling fluid systems is listed in the table on Page 93. A mini- mum amount of equipment is required for a simple clay water mud used in shallow to mcdiuln depth drilling. However, as drilling fluids become sophisticated, tests re- quired for adequately maintaining the system also be- come more complicated and exacting. In ultra deep drilling, temperature and pressure effects become more i~nportant. Extensive laboratory testing with high pres- sure--high temperature equipment may be needed. Note from the table that most common APl tests and equipment are not applicable to stable foam or air drilling fluids. Being a two-phase system, stable foam is sensitive to pressure and consequently its flow properties and characteristics are constantly changing as it is circu- lated down the work string and up the annulus which makes one-point testing meaningless. The few instru- merits required inclmh~ a calibrated gas hinter and an accurate liquid rate nt{'ter with at)l)rOl)ri;tte lU'essure gages. A co~i~dcr nt~dcl l~as }~'c~ dcvch>l~c{l tt~ cah:u- late injection pressure, downhole circulating pressures and velocities while circulating stabh: foam in a p:u'ticular well configuration, at various gas and liquid rates, with or without a bacl~-t)resst~re on the ann~lus discharge. Mud system equipm, nt Drilling fluid syste~ COml)t)nents req~iretl for ficient control and mai~tcnant:e of various fyi)es of tluids are listed in the first table. BOP equipment requirements depend upon the well being drilled. For air, mist or foam drilling, a rotating head or stripper assembly must be in- stalled to contain and dive.ri returns to a waste sump or tank. A variable choke is needed in the return line to permit controlling bott(m~ hole C(luivahn~t (:irculati~g density if balanced formation pressm'e drilling is to be achieved. Fomn returns may be collected in a relatively small tank wh('n cyclonic type foam sut)I)ressm' is used to dissipate sm'ge energy. Solids co~trol cquii)~cnt sl~ould receive maximum con- sideration for it is the ~()st im])ortant in tim economic control of drilling fluids. For unweighted m~d systems, particularly non-dislwrsctl, :t ba~flq of dcsi]ting con(~s, capa- ble of handling all mud returns, efficiently control solids buildup. It is essential that most solids be removed as they are drilled since r(,c>'cled for~nat[on solids 4lint: are reground and disi~t'rscd into the ~n~M-ar(~ v('ry diffi- cult to remove. For the same reasc)~, solMs control must be initiated as early as ]~ossil>]e a)~(l m:tintaincd continu- ously to prevent~'eg,,r{ mtct-Gne> solids l)t~ihlut). Solids control using cyclone desilters is efficient and economic with mud densities less than about 10.5 ppg (79 pc[). But with hi~l~{u' density muds, barite loss in the desilter increases. New mud cleaning equipment has proven to be an effective method of controlHn~ drilled solids buildup in intermediate weight muds and even Mud system equ:i}ment requirements Equipment Wellhead BOPs Rotating head or ~tripper Variable choke Surge chamber and mud separ- ator Discharge lines Solids removal Shaker screen Sand trap Desander Desilter Mud cleaner Centrifuge Degasser Treatment Mixing hopper Bulk barite Stirring & agitation Waste pit Normal Town lot Offshore Solids disposal Normal ' Town lot Offshore Liquid disposal Normal Town lot Offshore Biodegradability Ecological effects As required for well control -M-~y ~ Used rot under bal. drlg. May be used for back pressure control --Not used Water/l~ght treated clay Dispersed weighted As required for kick control May be used for under bal. drlg. Essential for kick control t%sential for kick con- trol to save gas cut mud Flow line to shakers Flow line to shakers choke line to surge tank and waste sump Dual w/med, screens Dual w/med, to tine screens 20-30 bbl. w/45' bof Be c~,reful not to dump tom-large diam. dump liquid mud Important-run ahead May be used to remove of desiltern coarse material ahead of desilting equipment Important to remove Not used fine stirs for low weight Important to remove Excludes It,. ~olids on fine silts for low weight medium weight mud Not used I~sential for economic control of high wt. muds .___ May be used ahead of Essential in kick eon- treatment if gas eh- trol for true wtz. countered Minimum required for Maximum for rapid wt. mixing day, get, them- increase on kicks teals Not used Essential in high wt. systems and kick con- trol Adequate for lost circ. Essential to prevent material, top guns best settling -- May be small to large Medium, will have depending on depth smaller amount of sol- and if used for settlin~ ids and more liquids large amt. solids ann Non-dispersed I- Unweighted--- ' -'--'~elghted ] _Al r~quired for kick control May be used for under bal. drlg. Oil muds Essential for klck control. May be used for As required for well control Not used Essential for kick back preraure control control F~ssential for kick control to reclaim gas cut E~qential to reclaim ex- mud pensive mud when gas cut Flow line to shskers, choke llne to surge tank Flow linc to shakers, and to waste sump choke line to surge tank and/or separator :)ouble deck w/ Double deek med. & Dual w/med, to flue. med. & fine screens fine screens Double deck w/fine important to settle coarse material ahead Important to sct. th~ of desander-desilter units sand. Be careful of mud Important to prevent overloading desilters or centrifuge Essential for Iow solids muds Essential for drilled ~lids control Preformed stable foam May be used to re- claim liquids and dump drilled solids Not recommended Generally positive, 1 pil)e ram ~ [Iydril Esseotial to diw:rt foam. Use rotating head w/Kelly and a striplmr w/power swivel I,;.~enGal for back pres- (;as. air and mist As required for control l'X~ential to divert tee turns to waste sump Not nsed Clean washed solids may be dumped overboard or hauled to shore on waste barges Non-oily fresh water fluids may be spread on land. Oily or salty fluids must be hauled to aw proved disposal site. May treat liquids to neutralize and dcflocculate to clarity before spreading or pumping into lakes or streams. Liquids may be solidified and mixed with soil. All liquids must be hauled to approved disposal site. Liquid waste is collected and pumped ashore through waste lines or barged ashore for disposal. Not nec&xl blay be used on high Not used wt. systmns Essential to prevent Needed if additive used Not m~edcd settliog and maintain but not after foamer viscosity added Small. will have large Small, will have large Small. solids very fine. amount of solids, very amount of solkts and very small liquid little liquids small amount of liquid Can foam into 500 bbl. Not used duo to dust tank and dcfoam l,robh:m (::in USO existing pro- Not used oormally duction 5~cilitics Solids are very clean Solids very fine but and can be buried clean, can bury Oil wet cuttings may Solidscoflccted in taok Not used. severe dust require different dis- after defoaming and proble,n posal si~e hauled to dump Oil-wet solids must be Solids carried by foam Not used uormally washed w/solvent and tlm~ prod. facillties to detergent to dump waste Methods of inciner- ;mall am'ts of liquids, l,ittle to no fluids for atingoily waste are be- May reclaim fluids disposal lng investigated after foam breaks on long time drilling jobs All solids must be hauled [o an approved disposal site. Disposal cost may be more than mud costs more solids. Solids are left in bottom of sump after liquids are removed and buried. Defloceulation treatmeut of liquids may help settle All waste collected in small steel tanks for treatment before disposal. liquids ..................... Most use small steel ~n-ks and haul all solids and liquids to an approved disposal site. Volumes of solids and liquids critical to both storage space and trucking costs. Useful on Medium weight muds Essential for high wt. mud control Essential for good kick control practict blaximum required to mix polymers: located after solids removal Not used IEssential in kick control Important to maintain uniform system Medium, will have large amount of solids and smaller amount of liquids Can be used by dump- lng into taok of solvent Not used Not used Can be used to reduce wt. Can be used if gas cut- ting a prohtem Maxinmm required for mixing new mud e~ ;lipment needed. Norms ly, foam is one-pa~ system, foani and solids go to w~te 8ulnp ()att use gas trap to st'p- arate gas and liquids Not required unle~q additives used -~o~ degradable Fresh water clay muds can be very beneficial to soils, particularly sandy soils. Sodium polyphosphatca used a~ thinners degrade to ortho phosphate fertil- izer. Lignite, lignins and tannins arc humic acids Lignosulfonates biode- Most polymers, starches, CMC are biode- gradable at low pH . _gradab'e ......... _._2__ Lignosulfonate muds Polymer muds should not be harmful as long should not be harmful as chromic compounds and chlorophenate provided chromates are ] bacteriaeides are excluded. not used Oil or oils' w~st.e may Small volumes of liq- l,itth? or no fluids to require a di~crc,t dis- uids can be discharged disp~xse of posal site or method into existing prod. fa- cilities _ -Not degradable Foamers, additives are Foamers used in mist are biodegradable biodcgradahlo Oil muds are no more l,'oam drilling compat- Air drlg. can result in hazardous than oil and iblc with ecology sioce serious dust problem should present no pro- relatively small vol- sincccuttingsareground blems with adequate umes of' liquids are very fine and blown out controls against spill- used. l)rld, cuttings are with air. Addition of age cud au adequate largeandnodustisgcn- foamer hellm, but does disposal system crated uot cure completely May uso Iow pre.~ure tral') to rcclahu gas Not nc,eded sure cnntro[ Surge chamber or cy- Not ns~4 chine type foam sup- presser wheu foaming into a tank ................................................................. Blowy llne to waste or Blowy line to w~to surge tank sump ........................ No snlids removal No~olidsremovalequil~ mont urn'd. Air ami mdhls to w~ BUHIp Hole stab~iizing capabilities Fluids Problem tlole Enlargement Water Base Oil Base Stable Foam Air or Mist , Soluble salts or solid Good if saturated with Excellent, unless material Good if foam base satu- Excellent if dry hydrocarbons salts oil soluble rated w/salts. Less water contact Erosion Can be excessive around packed hole assmnblies if Excellent control clue to Excessive near top of hole annular velocity in turbulence low annular velocity where expausion results high ann, veloc. Swelling Formations , Massive Good if properly Excellent with controlled Good with proper Excellent if dry inhibited salinity additives Interbedded, soft + Good if properly Excellent with controlled Good with proper l'oor due to excessive ero- hard inhibited salinity , additives sion or soft material Plastic shales, Poor Good using balanced Poor due I(} Iow hydro- l'oor due lo low hydro- geo-stressed salinity control static head static head , -- Sloullhtn~l Unconsolidated sand, Good w/sullqcient hydro- Good w/sutticient hydro- Good using pill technique l'oor due to excessive ero- gravel & breccia static head static head &back pressure technique sion, low hydrostatic head Micro-fractured shales Good if asphalt added to Excellent with asphalt Good with asplmlt add- Good unless wet plug fractures and balanced salinity itive Abnormal pressure/ Good w/sufficient Excellent with balanced Poor due to low Poor due to Iow shales hydrostatic salinity at reduced mud hydrostatic head hydrostatic head weights consisting of slugs of foam with bubbles of gas in between. Above a LVF of 0.25, foam becomes very wet and ap- proaches the lifting ability of water (LVF-1). Relative lifting force of sta~ble foam in the 0.025 LVF range is 10 times the lifting force of water at the same relative velocity. Lifting ability of 'foam also is dependent upon velocity, but to a lesser degree. Doubling foam velocity in the 0.025 LVF range results in 2¼-fold increase in lifting ability. Ho/e s tab ility Drilling fluids are categorized in the accompanying table by their ability to maintain hole stability in various types of troublesome formations. Additives which may be required to extend the range of preformed stable foam in these categories might include NaC1, KCL or CaCI2 foam solu- tions for salt and swelling formation drilling. Water loss additives include sodium carboxymethyl cellulose, poly- anionic cellulose and sodium polyacrylate and water dis- persible asphalts in micro-fractured shale drilling. Sloughing of unconsolidated sands and gravels after foam circulation is stopped has been successfully elimi- nated by spotting sufficient fluid on bottom to balance static formation pressure before coming out of the hole. Formation evaluation An important functi'on of a drilling fluid system--other than mechanically making a stable hole at an economic rate--is to make positive identification of the presence of water, oil, gas or steam possible while maintaining original well productivity (see ruble). Drill cuttings are important to formation identification WET FOAM LIFTING FORCE ON 3/16-INCH DIAMETER SPHERE DRY STABLE FOAM FOAM I t,o I 0.6 I 0.4 RELAI lYE VELOCITY 0[I , I ~ . 0 0; 0'.a [VF = LI0U[O VOLUME klO~lO VOL~ME + fiAS VOL~ME (at P ~ T) Fig. 5~Relative lifting force of preformed stable foam in- creases as its liquid volume decreases. Wet foam, which contains larger volumes of liquid, does not have as much lifting ability. (After Beyer, Millhone and Foote). How fluids affect ~'ormation evaluation Fluids Parameter Water Base Oil Base Stable Foam Air-Mist / 1 Cuttings Mush to ?~", water wet ~.~ to ~., oil wet to ~", no recycling, Dust to 4c, , no recycling minimum welt lng non-wetting Wtrelino logging Conductive fluids Non- Conductive fluids Non-conti, uous fluids No fluids 3~-875°F Temp. IES or Induction (w/SP) Induction (w/o SP) Induction (w/o Limit New tools Neutron Density Density l)ensit'y to 400° Sonic . NML Gamma Ray Gall/llla Ray Density Dipmeter Caliper Caliper Gamma Ray (w/knife contacts) Neutron (SN I') Neutron (SN I') DiPmeter Caliper i)ipmeler I)ipn~eter Caliper Neutron (w/knife c~mlacts) (w/knife contacts) Gamma Ray Sonic Identification Gas and oil Poor w/overbalance, may Poor w/overbalance, may Excellent, oil colors foam, 15xcellent but hazardous, kick w/underbalance kick w/underbalance gas encapsulated in p(~ssil>le a~o ignition water tilm, s;~t'(,r w/re- tm'ns diverted lo sump l)y pack,,ff head Steam Poor, masked by mud Poor, masked by mud Good, visible, s{mm ill)- ILxccllc~t, visible and overbalance and overbalance sorption Temperature Poor, absorbed by nmd Poor, absorbed by nmd Good, foam good insu- tLxcellent, f;tM return time lator Productivity testin~ Poor, requires isolation/ Poor, requires isolation/ Excellent, due to l~w l.;xcelhml, dt~c to low head, tools to reduce head tools to reduce head head h a za rd o u s w/h y d ro- carl)ohs Coring Poor, ttuids flush cores, P~r, fluids flush cores, Excellenl, g~o(I drilling C,~o(l, but high velocities water wet oil xvet rates, no tluid invasion, may cause erosion. Viii (;ood siituraiion oval- it prol)l(,,n ,m trips where uation. Fill a I~r()l)lem unconsolidated forma- on trips whcl'e tlII('OllSO- l. iOllS are encountered lidated for nations are encou n feted . ,,,.., , ,, .............. , ........ thus, consideration must be given to size, wetting and recycle. Stable foam is important since it offers maximum cutting size, minimum wetting and no recycling. With air there is no recycle and it is non-wetting but cuttings size tends to be very small, limiting their usefulness in deter- mining rgse~woir characteristics. A wide range of wireline logging tools are available for Mter-depenc ent to some degree and mu,9? 8ff De cons~tiered/n an op /mum &J///ng mud sysi'eng.' use in both conductive m~d ntm~co~cltmtivc ttt~itls. Stable foam and air are botl~ ~lon-conductive tlt~irts aml require contact type tools, l lowevcr, if a ~,~rmal strife of logs is essential, then a pill of apprOl)riate tlt~itl or nn~d could be spotted across the interval of i~terest before l(~gging and unloaded into a storage tank before drilling is resumed with air or foam. I)ctection ;n~d i(h'~tiii('atit~ ,ff l~ytlmcarl>,,t~s, gases steam in drilling fluid returns are essential to evaluation. Water base or oil base th~ids with excessive ()vm'balancit~g densities tend to mask (dl, gas or stca~n i~ returns and make identification ditlic'ull xx'itl~,~t~t t.l:tl),)rate i,~strt~mt'n- ration. Stable foam or air with low circulati~g densities, make hydrocarbon kte.~ttiticati(m si~u)le witl~ a ~finimum of equipment. But llw c(>~nl)inalio~ (>f l~ydrocarl)(ms and air under higt~ l)ressurc can })e lmzardot~s. At~t.() igl~ition may cause possible down hole fires. In a stable foam cir- culating system, oil mixcs with the foam for easy identifica- tion while formation.~,,ms. is incapsulated with air in a fihn of water. Since foam retluires a diverting l)ar'k-(>ff head at the surface and relatively large diaiueter disc:l~argc linc to the st~mi), all gas and }~y~lrocarbo~s are discharged at a safe distance from the rig. A l)ilot ligl~t ca~ l)e used to ignite any gas in the foan~ rctur~s. system equipm mt requlrementsm.~ at'd) [ I Non-dispersed · Equipment 'Water/lil~ht treated clay Dispersed weighted Unwelghted ! Weighted i ()il muds l'rcformed stable foam (/as, air and mist ., , LiquldActiveStOrage May be small to very Must bo adequate to Must be adeqnatp to fill hole on trips, nor- ~ Adeqmd,e to fill boh, on 20 to 100 hhl dMd,'d 10 1o 21) bid. foame~ t~ge, dependsondepth fill hole on tri ~s: nor- ~ really 300 to 700 bbls. ~ trips la.k m,c,h,d so . al ank f.r mi~ting and l~t circulation really 300 to 700 bbls. ' foamabh~ ~]ution emi [ be mix(d & t sod all,,r- May ~ small to very J Shouhl be adequate to 8honld be adequate to disptaec cement and Mavrcquiretwota.ks; ','N~,/,~I~ medcd if waL~,r None Rescue large ifu~M for ~ttling displace eemen~ for l~t circulation one'for new It, wt. m~ d supply mleqm~h', may i o,c for heavier mud [,.uscd to recycle foam con~amdrld.~hdsand smaller volumes of of hole solkls and smaller volumes of w~te solids dump,d, expen- cent. sin surging foam conLain W~e Mus~.. be adequate, to Adequate. to contain. Must be ,adequate to. con~ain large volume, M ioimal, , .since only. I.na, p ~ altair,t,, fie to. Dr'. ~ dna~ d flicu i to t waste liqui&~ ] drld. solids aud liquids [ liquids stye mud saved returns Dry storage Adequate lot mud and ~ Proper height and size ] Should be proper height, size mid location Ade,lUah~ for mtnl and NoL normally nettled NoL needed ehemieals , essential ~ for mud and chemical , chemical ' ,. .. Testing equipment for drilling fluids Water base ()il muds Properties -[~ ...................... measured or Non-dispersed Inverted em,lsion Preformed stable tested Normal melhod Clay dispersed clay ami polymer (ill base foam Air or mist Density & gradient APl beam balance, ppg Importan[in blowout control and lost circulation E~sen[ial for well conlrol l"lmv line d~',sity not No~ applicalfle or pcf. t~i/ft, mca,inghfl dne to Drc~qil)ilil,y of fluid Vlscosi(r ' ' ' Adequate for top hole and Marsh funnel 1,500 mi in~l quart ou~ Generally run, but not Generally run, hut not Nnt measurabk~ duc Lo No~ applicabh: shMlow clay muds ) meaningful meaningful Iow densit.y and high vis- 1~ cosity thru a small orifice Ro~tionalv~c~ime~r Rate of shear aC 300 and Required for dispersed { E~ntial for non- Import. an; in deep hot No~ applicable NeC applicabh~ ~00 rpm muds med. to deep drlg. ~ disl~rsed mud wells at. tcmperatur,~ Gel strength Shearometer.vi~osimc~er rotational Imlmrktn~ on deep wells [ disper~dhnp°rtan~ in non- "" hnport:m~wells a~ tempera~ur¢in deep ho~ Nu; applicable NoL applicable Filter loss Mw temp. and pres. · 1~ psi for 30 min.Adequate for top hole and medium depths No~ applicable most No~ apt licahlc Not applicable muds have no [o~q ¢~3 100 psi High temp. and pr~. ~00 psi for 30 min. up to ]g~ential on deep hot wells E~entlal in mud control Not npplieable Not applicable 400° F max. Filtrate tests Alkalinky Acid titration w/phenol- E~ential ou lign~ulf~ Im~rtan; on some l?iltra~e t.s; can be rue May be nsed on fo:sm so- Can bc tl~xt on luis~ phthalcin and methylhate systems i polymer sys[ents after extractiou with lut)on for corrosion con- soluti., orange proper solvent [.roi Salinity Silver nkra[e titration hnportant hnportaut Ibmd o. foam snlul, ion Not applicable and relurns 1.o determine formation dilution factor' Total hsrdne~ Versenate tkra~ion Important for Ca++ EswnLial on Ca++ sen- No~ applicable control sitive polymers pH CoIorimetric paint Adequate shallow wells, E~sential on polymer Not applicable Alqdical)le for corrosion C:m l~ us(al on mLst solu, electromet rte e~ential on (t~l~med systems (.trot roi t ion h,r cornmion control .. Resistivity Resis~ivky meter lmporhm[ to evaluation logging Non-conductive fluids Not applicabh~ Not alq)lic;tble Liquid-solids cement Eteetric retort Imporlan[ iu solkls control, weighted and lnw st3lids l';~cntial for dct,crmining A 1'1 cquqm~enl, m~[ alqfli~ A I'1 equipmeo/ not appli. systems oil and water contents cable, By collecting a cable solids-difficult tc ................ larger knmvn volume, dc- trap duo to size and high Sand conteng ~nd coutent tube Im~rtant cheek of desanding equipment Applicable using solvent foaming liquids and ~flids vvhx. ity 200 mes]l screen w~h ('all I)(' lilt'satired ............................................. , Cation exchange Methylene blue fi[ration important in high wt. I E~sentia[ in polymer Not applicable Not applieabh~ Not applicable capacity systems ~:...., ~ [ system Water-ln-oil emulsion Elee~rome[rie ~o[ applicable Not applicable Importan~ t,o measure- Not applicable No~ applicable stabilily ment of emulsion strength Circulalion rate Gpm--Strokes per Min. x Important for proof hole cleaning and jet drilling hnpor~antforpropcrhole Il.lc clcani,g ability llole cleaning dependent Gal. per stroke or programs cleaning and je~ drilling g.od at Iow rates. In- Ill)on very high air rates rpm x gal. per rev. design ('r,asing rate improves Sefm~l)ifferenfial meter li[6m~ alfilily and short- Hydrostatic Pressure (]radien[ x del)ih Amer- ]mpori.allt for blowout preventiol/and opLiultllll drill- J llij)orJ,itlJL for well Vt,tv iow, PIIll J)(, ct)n- Very Ii)w, (,:tllllO[ lie con- ada bmnb and Schlum- lng rate control tr.l~cd by { angi a ~;ts lr.lhM pr;u.tic:dly berger gradiometer and li(Itfi,l nd(~ and I)ack ............................... ; .................. i Circulating densitytlydrostatie plus eireu- Important for balanced hnportant w/shear thiu- Important. due to s]i{,~ Can be {,.nH}tlh. d by Very difficult [o determine lathJg annular pr~m.drilling and l~t circula- ning polymer muds thinning of oil (~ temp. computer nmdcl ' . tion ................ Circulation time Carbide, nitrates, dyes, Carbide, nit,rat, es, flake material and radioactive trac- Flake mat. trial :md radio- I)ye may give fair cite. l)itli('~ilt, to determine ] ' ae~ivefaceftake throughma~erialSchemicat~hefr°m°rsys~emradi°-sur' ers effective active tracers effective tracer time rcsults.ma~crialsRadi,aclive ............ , , , 'smh~ high-weight syste~ns. \.Vc]g~tcd ]xmd 1)asses ti~ ' throngh a bank of dcsilting cones and the undcrflow from the desilters is dropped onto a tine mesh vibrating screen. Barites can go through thc screen but, coarser drilled solids are discharged to the waste sump. Decant- ing centrifuges .usually are an effective, economic method of controlling drilled solids in drilling fluids heavier than 12 ppg (90 pcf). Mud treating and mixing equipment required for spe- cific drilling fluids should be carefully considered. Some systems may require ultra high shear rates for proper mixing and if the use of lost circulation materials is an- ticipated, then top guns should be provided. Bulk mud and barite handling facilities are necessary for quickly achieving uniform mud density needed for efficient kick control and to minimize transportation and rig labor costs. The time to get required mud !mndling equip~nent installed and operating properly is before th{: well is spudded. An effective method of getting requi.red About the authors .--~.~,~' Hutchison Anderson STANLEY O. HUTCHISON ?'cceivcd a U,.S. dcg?'ce in petroleum engineering from the University of California in 1951 a.~ld ha.s b,cen employed by SOCAL since tha~ ~imc. Prior ~o his assign- men~ ets projec~ engineer in charge of develop- ing new remedial techniques, he was engag.cd in various engineering jobs dealing with drill- ing .and producing operations. Mr. Hutchison is ~$resently a staff engineer in SOCAL's Tech- nological Dcv,elopmen~ Section at Oildale, Calif. GLEN W. ANDERSON joined Standard Oil Co. of California in 1964 as Northern Division drilling fl?rids engineer (t.f~cr g, ining experi- ence ~)ith Wilshire Oil Co., the S?t. pcrt;or Oil Co., Brown Mhd Co. and (ts a consult~;ng mud engineer. In 1969, h,c was on special assign- men~ to the Alaska Dis~ric~ designing and engineering drilling fl~tid sysgcms used by SOCAL in its North. Slope operations. He has developed foam testi~o and cc(tbtation pro- cedures, a,~d has cond~tcl'cd field tv'iaIs of ~h.e process in Crtlif ornia, Colorado, Text s and Cern- ada. M~'. A~derson is 1941 p,ctrolenm engineer- ing grad?ta~C of ~he Uni~:crsi~y of C~tli.fornia crt ' Berkeley, and is cwrrently in SOCAL's 7 cc ~- nological Dev.eloPm cn~ Section in Oildale, Calif. · letters recluesti~g tlrilli~g bids. 'l'he clrilli~g co~tract should not 1)c awarch'd t~ntil tim r(,q~ix'cd ('tl~til)~nc~t has been inspected and pr()ven to be itt ol)erating condition. Dis)osal co sicleralio,s l)rilling tluids a~,l cutti~gs (lisl~¢~s;tl, 1)t>tl~ tlt~t'i~g and after a well is drilled, are receiving lllOl't~ serious con- sideration in this age of ecological consci{)~sncss, l~ocal environmental protection regulations ~tay ~ake selection of the most desirable drilling fluid system inq)ractical or vcxy costly due to disl~osal rcstrictio~s, l"~r i~stancc, town lot drilling r)t)erations, diSl~(~sal costs ~:ty often ex- ceed actual drilling tluid costs. On locations whe.re water supply is lin~itcd, considera- tion should be given to thc usc of solitls removal C(luip- men{ in conjun(:ti(m with tloc(:~flating clw~ficals to claim w~tcr for reuse aml at the saint: ti~nc redt~cc dis- posal x'olumcs. , tanks'bv using a cyclone type fomn St~l)prcssor and by , . . . spraying with dtto:un~ng agent t() accelerat{: tlm release of the gaseous phase from foa~}al)le solutions. ()r, foam- able solution can be reclai~ed zuid recycled if foam turns arc passed through a large lilt allowi~g -% to escapc and solids to settle. But dcfoaming c}wmicals can- not bc used in this process. BIBI,IO(;RAIqlY "Drilling Fluids File," Il'odd Oil, .l;muarv 197't. Bobo, Roy "Surface mud ~y~tems," Oil C4 Gas Jou,nal..lan. 1~1, l:,'b. 1, Feb. 8, March 8, 1971. Binktcy Jolm F. "(:om'e]~t~ic drill ilt>v/alr llft-Nc~ ~,ay to crab lost circulatio;1" IV~ id' t~ I ~ ~34 lum ~16g. . Goins, W. C., and O'B~[en, T: J;., "New bh tl,-sik'ns drill h.,d faster," B'odd Oil, p. g3, lune .19~0; · ' , ',~'---" rmr t'rtr Bates, R. E., Ir., "Field results ol pcrcussmn a~r t~.,m<. ¢' · ' Tcch.. March 1995. McMordie, l)r. W. C., Jr., "Viscomctcr tests mud to 650° F," ()il Gas Journal, May 1 I,mnmus, J. I,. " new look at lost circulatlon," l'ttrolt~utn Engineer, Nm'ember 1~57. 1,renu{us J. I,., "Stir!coTe slmrics for I¢~,1 circulation ~,m~,d." I',t~,,leum Enk, ineer, September 19)8. ~[urrav 1. W. "Parasite tul~ing string solves lost chculathm probh'ms," Oil & C~} Jour., ~ay 27, 196~1. Kennedy. W. A.. ami Meyer, R. L., "I,ow-solids fluids r~,duce costs," Oil & Gas ]ourz Jul~ 15, 191)~. - ...... ,rzti~s of oll well drilling fluids," Gulf I u~lishing Co , lhmstm (1963). Eckel, John'R. "Ilow mud and hydraulics affect drill r:*le," Oil & Gas Jour., June 17, 1968. Moo[e, Dr. l'resmn, "l)rilling for th,' man on the ti<," 10-part scrles, Oil & Gas Jour., Scp~ 27t 19657;1an.' 17, 1966. Si~npson, lay P-, "Drilhng flums-'fro(my and tomorrow," ]our. o/ l'etr. Tech., Novdmber 1971. Chenevert, M. E., "Shah' cm)trol with balanced-aclivlty oil-contimmus nm(Is" Jour o/ Pt:tr. Trch., Oclobcr 1970. Me}hven. N. E., and B:u'flu'l, llorst, "Shale drillim: with oil muds," SPE paper 3679, November 197P. Anderson, G. W., llar~ison. T. F., and llutchlson. S. ()., "The use of stable foam circulatin< fluids," AA()DG Rotary Drilling (]onh'rence Trans- actions Air/Gas I)' iu<, Feb. 1966. Chambers, 'K., "Mud misting ht'll)s control watcr-scu,itix,' shnh'," Oil Gas ]our., March 6. 19t;7. Crews, S. II., "Bi< Itoh' drilling l)*ola'ess keyed I,~ vngim'erln~,' l'ct,olcum E,[,in,'er, October 196'1. Smiih. V., "New lecbnhlucS expand a '/~;a.~ h Illn,:," I'rt~,,I,'um December 1065. Ormsby Cleor<e,' "Pro ~'~ rigglm: boosts efficivncy o[ s~,l ( ~-removing equil)' mcnt" IA1)C Rotary hillim; (lmference Ih usto ~ M:uch Records{ L. R.. '"Mud syslems and well control,s' two-part series, l'ctro- [rum E~gtncer, March and April 1972. . (;oldsmitb, Rih'y, "(';]'aph spots cxt:ess[ve l}~('~;su~e ~,u~<cs ,,n ri,r," Oil Gas [ou~.. March 5, 1973. "Non-dispersed weighted mud pays off in th'cp drilling," liS, Id Oil, November 1972, p. West E R and O'B' cn T B.. "Mud selmrattus a~e x'ital to effective well c~ntr~*,'"'Wmld Oil. F[.b. I, 1973, p. 27. Wright T. R. lr. "On-site tlislmsal of mud," lffoHd Oil, ()ctobcr 1973, .p. 61. Millhone, R. S., llaskin, C. A., and Borer, A. lI., "Faclm's affecting foam c 'ct lation in oil wells," SPE paper ,B~OI, Oct, fl)er 1972. Anderson G. W. "Sl:tble foam circulalion cuts surface hole costs," Il'odd Oil, Septcm ~e) 1.071 I~ 3~-,12. . , .. lIutchison, S. O., and Ande~on G. W., ' l'ref(~z']m'( s ;I ,lc lO.ID al(IS work over drilling," ()il O: (';o~ Jour,. May 15, 1~72 pp 7-1-7'L Robinson, I,. 'Il.. and lh'ilhecker, J. K.. "S, lids c~,~trol in wci<hted drilling fluids," SPE paper ,16,t,1, October 1973. Beret A 11., M lbrme R. S. nnd From' R. W,, "Flow behavior of foam as a well clrculatin< fluid" 'SPE pq)er 3996. ()ctober 1~'177. Cromllng, J., "tlow geothermal wells are drilh'd and completed," Oil, December 1973, pp 43-45. OIL&GAS JOURNAL Near-gauge holes t:hrough permafrost Reprinted from the September 20, 1971 edition r THE ANNUAL JOURNA, DRILLING REP©i~:T Near-gauge. holes through permafrost The author... Glen W. Anderson is project engineer, Tech- nology Development Group, Standard Oil Co. of California, Western Operations Inc., Taft, Calif. He obtained a BS in petroleum engi- neering from University of California at Berke- ley in December 1941. Anderson joined Seca[ in 1964 as Northern vision drilling fluids Glen W. Anderson engineer after service with Wilshire Oil Co., The Superior Oil Co., Brown Mud Co., and as a consulting mud engineer. He spent the summer of 1969 on special assignment to the Alaska district, designing and engineering the drilling-fluid system used by Socal in their North Slope operation. Anderson has worked with stable foam since its conception in 1964 developing testing and evaluation procedures. He conducted field trials of the stab'.e- foam process in California, Colorado, Texas, and Canada since joining the technology de- velopment group in 1970. IN TWO w(,lls drilled in the Arctic Yukon of Canada, use of cold stable foam has achieved ttwsc results: · Increased penetration rates 2~/2-3 times that achieved with light-weight get mud. · Drilled near-gauge holes which showCtd insij4~ificanI waMn'd-out Ii(mN lhrot~gh ll,,. l)ern~afrosl. · Drilled full-size hole without devi- ation problems. A full-size rubber stabilizer 60 ft above the bit helped maintain straight hole. · Required only a minimun~ amount of extra equipment compared to a convenl ional rig. · Made 800 ft of large surface hole lhrough permafrost and achieved a savings of $12,000 compared to drilling with light-weight gel mud. A proved technique. For sew~ral years Standard Oil Co. of California (Socal) has been developing and per- fecting the technique of circulating a low-density, non-damaging, fluid called stable foam. TI'tis fluid has 1.)ten us{M for a wide range of applicali{m, such · l.incr drill-ins. · Drilling in tho producing zone. · Inner siring cleanouts of multiple completions. · Drilling loss-circulation intervals. · As hot foam, for pulling liners, stimulation, and paraffin removal. During hot-foam-developn~ent work the thermal properties of stable foam were investigated. It was discovered th, at stable foam has excellent insv' lng properties, as well as a low capaclty and poor heat conductance. Experience in drilling on the North Slope of Alaska during tlie winter and summer of 1969 made it apparent that a faster and more economic method of drilling permafrost is needed. Since stable foam had already demonstrated ,excellent hole-cleaning ability and fast penetration rates, we decided to i~5- vestigate its cold thermal properties in simulated permafrost cores. Cold-foam tests. In the laboratory, permafrost formation was simulated by forming hollow cores of coarse sand, saturating them with water, and freezing thern. Cooling coils were fab- ricated for our laboratory stable-foam generating equipment to enable pre- cooling both the foam solution and the preformed foam before circulation past the simulated permafrost. At first, it was assumed that freez- inz-.po:.nt suppressants would be re- quired'in the foam solution, tIowever, tests with 10 to 20 vol % isopropyl al- cohol and ethylene glycol in the foam colution cfiused severe erosion when circulated in the simulated permafrost cores. Similar tests with sodium chlo- ride foam solutions indicated thai 15- 20 xvt % caused some hole enlarge- meat in permafrost cores, 10ut not as severe as the alcohols. Stable foams formed with 10 to 15 wt % NaC1 solu- tions gave nominal hole enlargement and formed very stable foams. It is thought that the alcohols and concen- trated brines have a deicing effect on the permafrost, causing melting and a resultant hole enlargement. The next tests were performed with- out freeze-point suppressants. It was found that by controlling the temPer- ature o(the foam solution just above freezing (35°-45° F.) a stable foam could be formed. When circulated past the simulated 'permafrost core, this caused very little h01e enlargement. However, after standing for 1[,~ hr without circulation, the freshwater foam was frozen in the simulated core. The top half was light foam frozen in a cellular state, and the bottom half-- below the end of the circulation tube-- was solid ice. From these limited tests it was. con- cluded that cold stable foam could be circulated past simulated permafrost without serious melting or erosion, pro- vided injection temperature is main- tained a few degrees above the freez- ing point of the foaming solution. In pile holes and slt:.,!.low conductor holes, temperature-con! 'olled freshwater foams could be used. In the deeper holes, however, where trip time and casing-running time are extensive, the use of 10% sodium chloride foams might be required to prevent down- hole freezing and bridging. The field trial. Our next problem was to find a well in the permafrost area for a field trial. With the lim- ited drilling activity on the North Slope after the lease sale, our hopes were dimmed. Then, Chevron-Standard Ltd., Socal's Canadian affiliatae, became 'interested in the use of stable foam for drilling permafrost. After study and discussion with the Socal technology development group, Chevron-Standard decided to give stable foam a field test in their 1971 Arctic drilling pro- gram in the Eagle Plains area, Yu- kon, Terr. Late in 1970, two drilling rigs and one set of stable-foam equipment were moved by truck from Edmonton, Alta., 1,900 miles north, via Whitehorse, Yu- kon, Terr., to the Eagle Plains loca- tions a few miles south of the Arctic Circle. First well to use cold stable foam was D-22 Shaeffer Creek. Twenty- in conduclor pipe had been prex'io'dslv "mented at 78 ft with a small rig. tlI'ing rig-up and lhe stable-foam drilling of the surface hoh:, the lem- peralure ranged from 30" to 70° F, bt'low zcm, A critical part of lbo stable-foam drilling process in Ibis sut)zoro envir- onment was preventing the freshwater foam from freezing in the 150-ft line from the foam-generating equipment to the rig stand pipe. This problem ~w~s solved by circnlating lhe foam through a line in the hot suitcase walk- xvay rtmning alongside the rig. This hot suitcase is an insulated t0ox con- taining all BOI'-conlrol lines, water lines, air tine~, ami steam lines from auxiliary eqnipmont lo tho rig floor. All foam-solution water was drawn from lbo sleamq~ealod rig sim'age lank. Tho tomporaluro of the waleF w[/s very erratic as cold water was added, periodically from a xvater-haul- ing truck. Drilling resulls. The well was spu(lded Jan. ~2, with a lTd,-in, three- cone bil and one 10-in. drill collar. Foam circulalion was established with 400 scfm air an(t 20 ~pm of ~,5% fresh- water f():~m s(flulion al l.tO psi. Good Eagle Plains location tar pipe was cleaned out, re tng ce~ment and slushy ice. Penetration rate was slow initially due to lack of weight on the large bit and the slow rotation. It increased when 10-in. drill collars were clear of tile conductor. After clearing the conductor pipe with the 10-in. collars, connections were made with 7-in. drill collars and the rotary speed was increased to 120 cpm with bit weights of 5,000 to 10,000 lb. Penetration averaged 34 ft/hr with intervals as high as 60 ft/hr. This was phenomenally high for this area. The stable foam returns contained an abundance of fine silt and sand. Average air rate was 300 scfm with 15 to 20 gpm of ½% foam solution at pressures of 145 to 180 psi. Foam so- lution temperature varied from 50° to 70° F. because equipment was not available for more precise control of storage-water temperature. The tem- perature of the return foam was 38°- 45° F. Foam disposal was not a problem. It froze almost immediately into a por- ous, brittle mass which was destroyed by the slightest disturbance after con- tact with the subzero air. The sump was shallow and small due to inabil- ity to dig the frozen ground. None I less, a fine spray of diesel ()il contain- lng a foam suppressant was very ef- fective in destroying the foam, even after it was frozen. Formation sampling and gas detec- tion were problems in this subzero environment. The cold stable foam would not drop formation samples in the blooie line and, of course, the foam froze as soon as it hit the air. The best method of securing formation samples was to collect a drum of foam at the blooie line and haul it to a heated area where the foam collapsed and formation samples could be col- lected. Several methods for collecting gas samples were attempted. None were satisfactory due to freezing in the gas trap or in the small line to the log- ging unit. Safety of stable foam. While taking a deviation survey at 699 ft, formation gas unloaded the stable foam from the annulus and was then detected at the end of the. blooie line. For safety, the gas was flared at the blooie line which was 150 ft from the rig. A check valve installed tiigh in the drill string prevented back flow, and the rotating head diverted all returns oul Ihe blooie line. APlmrenlly tile sta- bh: foan~ enlr~l)ped all formation gas while circulating, I)ut there was suffi- cient formalion pressure for the gas to unload the well. This is an excellent example of the safely lhat can be realized by using slable forum, tlowever, since equipment was not available on this first field Irial eiflmr for safety round tripping a bil, or for delco[lng formalion gas i~ tl~e returns, it was decided to kill the well with mud before drilling ahead. The hazard potential of encountering shalloxv gas sands was further indicat- ed when 200 bbl of 8.8-1b/gal mud was lost inlo the formation before cir- culation was established. As a result of this problem of gas dc~ection, a new gas separalor was designed for the second well. The' gas Irap off ~he blooie line was enclosed in a box and heated with steam. This rangement proved very satisfactory for gas detection on the second well. Stable foam vs. mud. As a result of the changeover to mud drilling, an excellent drilling rate comparison can be made. A total of 618 ft of 17~-in. hole was drilled wifl~ stable foan~ in 18½ hr for an average of 3t ft/hr. Deviation of Cold-foam system t'lg. 2 Rig-steam J / Meter J lO-bbl foam-A ~ ~ I solution ,:1 I,,',,-~EL' I (') drum k,.J Foam f~ generdor ~ Recording p ....... : I I meter~ ~ ~u'~['~ J Compressor, J J~J t~ : J 800cfm, I 300 psi J ~ Thermometers~-t ' ' ~ Adjustable : flow bean J I · __ t "' Enclosure for Excess- winter air vent operations 1 Foonl bleed-off line Hot suilcase "°Ormafro __ Rotating bead Gas to logging unit ~team chest gas separator Blooio line drum L[GEND ---:::: ;,:, .... 'the hole was maintained und wittmut drill-string stabilization. Bit No. 2 was run in both foam and mud and 128 ft was drilled with stable foam in 33A hr (34.2 ft/hr). After changing over to 8.8-1b/gal gel mud, 241 ft was drilled in 17~A hr (14.0 ft/ hr), and hole deviation went from 7/a° to i~A°. After bit No. 2 was pulled, it was decided to rat hole ahead with 121`4-in. hole to try to straighten the hole. The 12~¼-in. hole was drilled to 1,202 ft, making 262 ft in 171,4 hr (15.2 ft/hr) with no reduction in deviation. Opening hole to 17½-in. required two bits and a total of 241,4 hr; final deviation was 1½°. Second field trial. After completion of foam'drilling at the Shaeffer Creek well, the foam-generating equipment was trucked 75 miles south to the: 1-13 East Porcupine location. During rig-up and drilling at the new location, out- side temperature was much improved, ranging from --5° to --30° F., which speeded work. The well was spudded Feb. 10 with the same drilling assembly and foam- circulating rates as the previous well. Drilling proceeded smoothly, but pene- tration rates were not as spectacular as at the first location, ranging from 8 to 22 ft/hr. Apparently, the forma- tions in this area are much more com- pacted than in the first area. Also, we were limited to a maximum of 70 rpm by severe whipping of the drill pipe in the conductor pipe. On the second bit run, a 17½-in. rubber stabilizer was placed on top of the 10-in. collars, 60 ft above the bit. This did not solve the whipping problem, but did help straighten the hole from 1° to ~,4o at the 799.ft TD. The ~table foam performed with 300 scfm air and 15-20 gpm of 3A% fresh- water foam solution at 150-psi injec- tion pressure yielded abundant foam returns which had excellent carrying capacity. Foam inlet temperature av- eraged 65° F.; foam outlet, 45° F. Three 17½-in. bits were run for a total footage of 739 ft in 54aA rotating hours (13.5 ft/hr). After displacing with gel mud before logging, an additional 5 ft of hole was drilled in 1~,4 hr (4 ft/hr). The bits run during foam drilling showed only slight tooth wear, nor- mai bearing wear, and were in gauge. However, they had abnormal skirt wear with a smooth 3~-in. wide by ~/4-in. deep groove about 2 in. above Foam vs mud drilling - @ 78 ft, dev. 11/4 ~ 't ' Bit No. 1, ---1493 ~tin 14¥4 hr;{ · l ~'5'in-[ I Ave~age33.4ft/hr/ / ~T. I ~----1 ....128 ft in 33/4 hr; J. ~1 I . [ Average 34.2fi/hr ......... '- --C~angea to ~ 8 Ih'/g~l gel mud Bit No, 2 I / [ [ .... '~ ' I / I I Mud drilled - ,.:,-:-4-4-4-. ....... t- I i - - .... ~ pros ~wo /I t ~ / ~-T .... 1 .... ] .... ~ } ...... l foam drilling ,1, 1, / I I I I I I '1 I 0 10 20 30 40 50 60 Rolating time, hr Dam collected at J Mud drilled - 1 2 ~/4-in. hole; opened to 17~/~ in. Average 6.3 It/hr Aclutd time, foam and mud drilling ' 70 80 SWEEP efficiency of displacing foam with water is demonstrated here. Bulks are 12-in. diameter; model simulates 27/8-in. casing with 48-in. washouts. SIMULATED permafrost core (top) was tested on laboratory cold-foam equipment (below). Tests included evaluation of freeze-point suppressants. can bc solved 19, runnin.~ I~its with e×- ti) the bottom of the ht)h~ for carry anything it can gc't under, but docs not have a g~d jet impact ef- fect because it is a compressible fluid. Caliper in permafrost. The first well was logged at 1,202 ft and indicated permafrost to approximately 3(~) ft. A two-armed hole caliper measured a maximun~ hole size of 20 in. near the surfaco, lat>erin~ 17~4~ in. al 200 fl, and then ~auge hole to 1,200 ft with no washc'.d-out sections. In the second well, lhe botlom of the pc, rmafrost was picked at 350 fl. ttole caliper indicated a tataercd hole rang- thc Stll'fa('c, lo 21 in. at Ibc of Ibc permafrost, lo 19 in. at 500 fi, and then g'mLc lo 700 fl. Our inability to maintain thc foam solution temper- ature in the desired 35:'-d5' F. range and the slower penetration rate on the second well probably contributed to thc slighlly lar3zcr hoh' size. Cost o[ slable foam. 'l'lw st:~bl{' process rc(luircs a n/inin~um (>[ extra ('(luipmcnt su(rh as: air fo:~n~-inje, ction t) umP, foam-solution ill/(t lkluid Iilclcl's, l'ol;l!illJ1 head, alqd ('()st of drilling in this run~ote area with n~ud was calculated Io be $227/hr. (;(>st of drilling with stablo fo:~m was $275/hr, 10ut rcsultod in 2~,52-3 times moro hole. It is eslimatud lhal Ih(, usc of stable fo:~m on thc mw(oral well resulted in a s:~vin~ of S12,000, cvt'n aflcr allowing for Ibc ('osl of Iransporlation and sl:~ndby limo duo Io weathor. Another operalor drilled in this area using straighl air. Itc had ~ood Nme- tratio~l talcs without excessive hole enlargement, trot air roquirements wore five limes lhost~ used with stable fo3m. On a 1G-hr/d:zy opcralin?, basis, , thc (;()sls roi' ail' drillim~ would bc ''( as compnred Io $4{;g for stable-foam drilling. 'l'he Iranspm'lalion ('ost in alld out of Il]is remote aru:t would, propof tionatoly, favor stab]c' foam since it rccluires only two trails as comp:ri'ed to six units for air (lt'illing. Recommended for future. On fulure jobs, improvements could likely be made by using: · A (;-in. s~oam-jackotcd blooie line fabricated for winter opcrntions. The 12-in. blooio line froze up internally to an effective diameter of only after:, 6 days of winter operations at 60°-70© F. below zero. * A more flexible compressor com- bination, such as: a high-volume, low- pressure compressor, plus a high- pressure booster or two high-pressure, medium-volume units to permit deeper drilling with adequate pressure for good hole cleaning. · .An independent water supply for the stable foam process with controls to maintain the foam solution temper- ature in the'35°-45° F. range. ~ Extended-nozzle bits to improve bottom-hole cleaning. Two-cone bits permit the use of sturdy extended noz- zles and have demonstrated excellent top-hole penetration rates. ~ A foam-disposal sump with a slop- ing ramp from the end of the blooie line into a wide area for foam expan- sion and collapse. Types of permafrost. The permafrost formation in Yukon, Terr., is fine grained silts and sand. When frozen it presents a firm formation which is difficult to drill with large-diameter bits. This formation is competent and does not wash' out or erode unless ex- posed to excessive heat. In contrast, the permafrost forma- tion on the North Slope of Alaska is coarse gravel to sand and does not present too much of a problem pene- tration-wise. This coarse formation tends to erode and wash out easily, and as hole size increases, it becomes difficult to get adequate hole cleaning due to the size of the gravel. Cold stable foam should be bene- ficial on both problems mentioned above. The low heat content and poor heat conductance of stable foam should prevent ,hole enlargement. The high viscosity of foam should result in bet- ter hole cleaning. Another advantage is that foam returns are discharged directly to the sump, eliminating the problems of handling large volumes of cuttings at the surface. Importance of hole gauge. It has re- cently been brought' to our attention that serious surface-casing problems are developing in the completed North Slope wells. Reason is the refreezing of water-base muds left in the annulus washed-out areas. Diligent efforts have been made to displace the annulus be- tween the 20-in. casing and the per- mafrost formation with either cement or an oil-base pack fluid. However, these viscous fluids tend to channel through the wash-outs and leave freez- FROZEN foam piles up in the sump. Note the 12-in. blooie line which has frozen internally to an effective diameter of only 3-in. SUPERIOR carrying capacity of the cold stable foam for large-diameter holes is demonstrated here by the returns from drilling. FOR detecting gas in foam returns, a "hot box" arrangement was rigged up. Gas trap off the blooie line is enclosed and heated with steam. THIS disposal sump design proved very satisfactory. Note the sample barrel and excellent returns Of the stable foam. le fluids in the annulus. Stable-foam drilling should provide an excellent answer to this problem. A hole drilled wilh stable foam should prevent excessive hole enlargement and when displaced with a denser fluid, such as cement or oil-base pack, should give 100% sweep efficiency. Laboratory tests indicate that even wa- ter will float out foam from large bulbs efficiently. Even if a small amount of foam should conceivably be trapped in the hole, it should not present a refrcezing problem, since it contains less than 2% water by volume. The ability to drill a hole lhrough pt, rmafrost with slat)lc foan~ should rcsull in lar?,c savings in Iht' cos[ of coin(mi or Ih(' ()il-base pack. fluids used to fill lhe annulus between the surface casing and thc open hole. As mu'ch as $10f),000 has been spent for cement on washed-out holes through permafrost. One well cored cement 50 fl frolll lhe ctmler of lhc h{)le allot Slope. Ecology. Since stable fmtm contains only air, fresh waler, and a small percentage of fonming agent which is biod(,gradablc, it shouht not affect ccoh)gy. Other applications. Drilling and meriting of large conductor pipe in permafrost is slow and costly when drilled dry with an ice bucket. Con- veniional rotary bits could speed pen- ctration if a small 'rig were adapted to stable-foam drilling. Sill(:c all pc. rn~alqCl]t structures on [)cri~lafrost nltlSt bc sci Olq piling, a g~'cat number of pile holt,s must be drilh~cl, tIerc, Ioo, ~l~tbl(~ fo:tm could be easily adaplcd and should speed operations. I)ccpcr scislno?,r',~phic and core holes lhrough permafrost and wet forma- tions could be drilled with minimum air volume by a simple adaptation of existing rigs to slable-fo:~m drilling. Acknowletlgment The author thanks Standard Oil Co. of California for permission to publish this article. Thanks also to S. O. ttutchinson, R. S. Millhone, and C. A. ttaskin for their assistance in develop- ing information for this article. Spe- cial appreciation is expressed to R. C. Richardson and R. K. Connon of (~hevron-Standard Ltd. for their splen- did c~peration in this first field trial of stable-foam permafrost drilling. Air, mist and foam drilling: A look at latest techniques R. A. Hook and L. W. Cooper, Amoco Production Co., and B. R. 'Payne, E. W. Moran Drilling Co., Inc. ,10-second summary Advantages and disadvantages of mist and foam drilling, are dis- cussed in this first half of a two-part article. Special .equipment used in air drilling is described and air require- ments for air, mist and foam drilling are given. Also, a procedure for un- loading and drying the hole is out- lined. "Air and gas drilling techniques can reduce drilling time and cut costs. 'Other advantages include immediate !and continuous hydrocarbon detection, i. mifiimum damage to liquid sensitive 2ay zones, better control of lost circu- :ion and recovery of clca~mr cores. 0f air drilli~q;, zz~dilicatit,~s sttcl~ as mist or foa~ drilling, t~ni¢luC C¢lt~il>- meat re¢l~irc~,:nts arid {lowt~l~ole }r0bh,~s tl~;tt h;tvc 1~¢',¢'~ e~ct~t~ntcrc¢l. ~eclal attention is given to l)rcs{,~ting techniques developed to 'pr~ent or trol downhole probletns. ADVANTAGES AND DISADVANTAGES Air is the ultimate low density drill- media. To achieve Ol~tinmm re- sults and greatest economy from air drilling, there are several factors which should be considered. Hard forma- tions which are dry or produce rela- tively few formation liquids providc the best results while air drilling. When the formation is completely dry, or the influx of liquids is slight enough to be absorbed in the air stream, the drill cuttings return to thc surface in the forn~ of dust. Also, this allows for immediate and continuous evaluation of hydrocarbons. Other proven advantages for thc use o£ air are: · Low cost 10 ~ 6 INDIANA LIMESTONE , 150-450 MD. PERMEABILITY 1%IN.TWO-CONE ROCK BI' 6,000 PSI OVERBURDEN 50 RPM 1,000 LB. BIT WT. 1,000 2,000 3,000 4,000 5,000 DIFFERENTIAL PRESSURE - PSI Fig. l~As differontial prossuro (fluid col- umn prossure in tho boroholo In oxcoss of formation poro prossuro) incroasos, penetration rate decreases. Tt~us air drill- ing, which reduces differential pressure to a minimum, usually results in much higher drilling rates. · Increased penetration rate · Longer bit life · Better control in cavernous and lost circulation areas · Minimum damage to liquid sen- sitive pay zones. 'l'}~c fact tl~at the drill string will always I)c on bottott~ when gas is countered is a big advat~tage in well control. If the hole is gas free when a trip is made, it will be gas free when t}~e new bit is returned to bottom. Nlud-filled holes will sometimes allow gas to enter the wellbore on trips, due to reduced hydrostatic I)ressure, and create well'control {,'oblcms. (las al- ready I~enctratcd d~ring air drilling ol~erati~ms will enter the wcllbore on trips. I lowcvcr, tills gas is always a k~own quantity and can easily he jcttc~l away fro~ tlw ri~ and olmrat- i,,l~ i.',s,,,,,,,'{ I,>. ,,si,,g .leis .t~ tim ~q~cr:~ti~,~ will I~e tliscum'd lalcr. When water is encou~tercd, mist I>c ~sc{I. Xlist {Irilli~g can handle ~1)~ lo al){n~t 2(~0 I>arrcls per I~om' water~ i~l~x. WIm~ s~rface In'Csst~res exceed tim li~it of Ihe air cm~l~ressor equip- 150 on Roader Service Card 95 BEST GAGE CONE BLANK SHOULD GO HERE SECOND BEST GAGE CONE Fig. 2wBlanking in one jet of a three cone bit can improve bit life by restricting air flow through jets and forcing more air through air tubes and across bearings. ment, aerated or slug drilling can ac- commodate larger volumes of water. Other disadvantages to ai'r drilling arc: · Downhole fires and explosions · Sloughing of formations (when dry or wet) · Soft formations. These disadvantages will reduce the efficiency of air drilling but with equip:nent available today, they can be handled. Increased penetration rate is anmng static l>rcssurc a:id aids fractt:ri::g. ])ill'crc:tit;ti i>r,tsst:~c irt is the difference between fluid column (l:'ilH~ ]:J::(l. ActuaZ rock relllovaJ or cuttin~ done b7 subjecting the rock to com- pressive loads,greater than its ultimate strength. As the bit rotates, rock is caused to fail or £racture under this dynamic loading. Grushcd formation or chips literally explode off bottom and are swept into the air stream and are carried to the surface. This ex- plosion or rapid manner in which chips are removed from bottom is a result of maximum differential pres- sure into the well,re. Chips which are removed from tim bottom exist in a range of sizes from fine to coarse. ~ these particles start u/) the anr]ulus, the larger sizes are ground and pulverized by the drill string. Also, the ])igh velocity forces 11:(' itt tlic [aster p('nctrati(m rates wJtii air, thai ;: (I,lill-<dl' {('si lic ('~,~({:t(:l(,(l <)v('r ;~t lilt wcJ~l:I ;:::(I rot;~:'y Sl~CC(l ov('r 61/ feet and average the })enctratio:~ rate. q'}m:: change either bit weight or rpm nd repeat the process. Tl:is procedure averages out illin forlnation changes 'i and will provide thc optimum pene- trati(m l';~tc. Bit lX'rfo,':nancc is a:t irnportant factor in any drilli:lg olx'ration. For air drilling, select the bit with the best gauge protection. In some cases, this will necessitate counting and com- {~aring the outer row of inserts or teeth. Tl:e bit with the most outer row inserts or teeth will give the best per- fori~:ance by holding its gage longer. Bits going out of gage are most prow:lent :wi:er: hard, abrasive quartz- ire sands are drilled. Reaming behind an out-of-gage .bit onuses premature bearing failure of the bit being used to ream. This is cat:sed by a pincl:ed bit when the bit reaches bottom after reaming. Premature bearing failure shortens bit life and necessitates the use of more bits per well, }lard formation insert type bits are used in most air drilling operations. Today's market offers bits made for air drilling with some manufactured for mining operations. These mining bits have OD tolerances ranging from - zero to + ~ inch, a 7~-inch bit could be no smaller than 7}~ inch but could be as large as 8~ inch. Alsh some bits are manufactured for oil field air drilling. These bits have out- side diameter spehi(icat~ons wlq[ch are j~J the same as bits horn:ally used to drill When an air bit is used, experience has shown that bit life and penetra- tion rate can be improved by blanking one jet nozzle. When a blank is used in a jet nozzle, the blank should ~ lx:twcc, n tim cones with the most gage inserts, Fig. 2. q'lm reason is that thc cones (m each side of tim blank will }war :nest of t}le c::tting load while drilli~:l(. '['}tcr(:forc, these cones should have tire tm)st inserts and best gauge:: {)l'OtC('I{Oll. LIlllder ll():'lIlal conditJons, j <'1""' ,,,1 i,.~l,.,l will: 20/32-i::ch or 2'l/:l;~-l,:: I: ici,, I~it lilt' [x'ciu~st' it restricts :dr flow ,~{~,~' ;ti,' IIs,',,::l,,{i tls,' ::ir ti:Ires and ::ci'~ss t{Ic I:c;:ri:~gs. 'l']:is kce}>s the {,~'~:,'i:,/5 t'~,,h'r ;::,l ch.ti:ir:' ;~ml will (.xtl.lit/ I)il life. '['}m {)l'l,[Slll'('. incrca~ dm' t, l,l:~:~ki:~g o::e l)il jet,' is ab0u 10 to 15 psig. Conl/'nuod on pageI VALVE MANIFOLD OPTIONAL . SOAP PUMP FLOWMETER BOOSTER COMPRESSORS Fig. 3--A valve manifold is welded to the standpipe, downstream of compressors to feed compressed air to blooie line gas jets during trips. MOVING SEAL HERE 1 GAS OR AIR DOWN THRU KELLY ROTATES WITH KELLY ~ BLOW OFF ,// CUTTINGS A DISTANCE FROM RIG Fig. 4--A rotating drilling head is required, to seal tho annulus at the surface and divert air and dust through the blooie line away from the rig, 'l'llt; scccmci adVa~t;:ge I{) a jcl i~ Imller I,,h' ch:a,~i~u~, Ill()S[ C;~$(~S by f;islCl' l)CIl('.[l';lli()ll, 'l'Jw. blank ~cL [orccs the air Lo flow across tile bit face, relnoving ctitti~lgs from tile C('IIIO, I' Iii tile l)it ;lll(t ~ould I)e tral)l)Cd under the I)i[. melriral .italini can, i~l(ler ccrlain bit center. Effects vary witl~ forma- tions and possible advantag~ must be weiglmd against negatives, such as reduced bit-bearing cooling. AIR DRILLING EQUIPMENT ri~.,, l~ ;~ air (Irilli~g ~l~(,r;~lJ(m si,nixie. M,~st liqt~i~l ami solids l~andling C~lUilmmnt slmuld consist of In:i:ll~ ;uid al)(mt 1,5()0 I)arrels waler storage (sLeel mud pits can be used). A valve manilold is welded to thc ~"ntll)ipe on the rig floor, Fig. 3. The .'dware, valves and lines in this :::anifold si:or:Id be sized and pressure :'atcd t~> i~rovitle :~:i::i:::::::: f:'iction h)sscs and z~axi~nu~n ol)erating pres- Stl I'CS. A rotating ch'illing head is essential, l"ig. 4. 'l'}m rotatist!.; head znaintains a const;tnt se:ti l;tl'Otlncl all rotating elc~mnts in the drill string except large diameter pieces such as large drill collars, reamers and the bit. The rubber seal unit will seal around any shape (kelly or drill pipe). The Pack- lng element rotates with the drill string. Tiffs allows the drill cuttings or dust to be directed out the flanged ot~tlet and away from the rig through the bl~ie line. Prol)er align:ncnt of the rotating }mad is essential, to save time on con- nec:tions and ])rcvcnt ~nctue wear on the rubber element aiid t)earing struc- ture. A method for proper alignment of the head is to set a drill collar on the slips in the rotary table and center tim collar in the rotating head. Centering can i)e done i)y using a steel tape line and measuring from the ID of the rotating head to the OD of the drill collar. Corrections in Mign- mcnt can be nm(lc with chains and boomers. When thc rotating head is i)ropcrly aligned and centered, braces can be attached to {he head and to the sub-structure. Welding these })races will prevent movement and misalign- mcnt during drilling operations. The life of the rubber element in the rotating head can ~ extended by keeping the kelly well lubricated while drilling. Tills is easily done by pour- lng water or li(luid SOal) o~l top of tim rubber element after each connec- tion. Oil can be used for kelly lubri- cation, })ut it ten(Is to pack cuttings in ti,: rotating head which can re- strict air flow. ()Il:er I)h)w()llt (:~)nt:'()l ('(l::il)~lmnt is st;:ck siz('(l I(> ~Jmel :u~ticil~alcd I)rcs- si~re retlt~ire~le~lts is sull'icie~lt. Air Cmnl.'Cssm's are ;tv:~il;tl~le xvl~ich l)r(witle a(JCtltlatc air volu~ms along ~js,'(I ,~il liul(l :Jlr ('~,~l~'~'ss{)~' is ;~ I~osi- tire (lislfla('c~uent, (l(}tll)l(' acting, re- cilmx'ati~g, two or tl~ree-stage i~nit. 'l'l~is tyl)c oll'ers a wide range of sizes a~d press~u'e rati~gs' necessary for an Circle 152 on Reader Service Card ~ A PR I L 1 977 /~ FLANGE F /lNG TO FLUID '- GAS SNIFFER PI.~LOT LIGHT SAMPLE CATCHER "~ / x PRIMARY JET ~ \ / SECONDARY JET - ' -' / RESERVE / ~ ~// ,ROTATING HEAD J ~" DE-DUSTER ~i PIT WALL 3b,' '~-=-'-'-' ' _ .: ....: - IR LINE FROM ' I ' I' ) · (RESERVE PUMP )~ %Io~L.~J~, ,-, .,.~, ~. MANIFOLD ~- ......... ~"~::.. - :',s0, To ~00, 2" AIR LINE FROM/'""~'~'-~-~ ' t L_J OPTIONAL HOOK UP STANDPIPE '"".) I '/ FOR MUD. Fig. 5--The blooie line should be 150 to 200 feet long and end at a burn pit. Steel pits and reserve pits should be provided to allow conversion to mud drilling. 1" COLLAR SQUEEZED ; -~--~- J i WATER FROM FOR SPRAY EFFECT --18"-- ~ WATER PUMP "'%., ,/ J----~"-.~-' , ' ~ ~ METAL SHIELD BLOOIE LINE ' END VIEW ANGLE IRON INSIDE BLOOIE LINE' 2" NIPPLE 2" UNION~, AIR FROM STANDPIPE MANIFQLD, · 4" X 2" SWEDGE .-.... ~ r"'-- 2" UNION 'A" PLATE --~"'~ ( %,7 TQ 1" TUBING ' COVERED WITH o 4" COLLAR CUT IN HALF ..... '~ ~2~ ...... 2 .... ~ 20 7 AIR AIR FLOW FLOW ~ BLOOIE LINE I [ BLOOIE LINE Fig. 6--Important parts of the blooie line include the primary and secondary jots (boHom-lofl and right, respectively), do-dusler (lop) and sample cnlchor ]ltllllb('f (if (t()IIIJ)I'('S~()I% ill ;I will ~l<,l)(,~l ~,l II~(, ;~ir wd,~,:m (luired to d,'il{ cllicie~tly. o,m air co,,~p,'esso,- h,,' oil field will provide '100 to {,20()(',,b~c fee( of air ])(,t' tt~i~t~te at 300 to 320 l~sig J{n u m l)rcsstlrc. A 1.)~ilive (li~l)lac(,~),,~ll ~.,~f;,cl~r'<'r~ carl v(,l~,]~,, (n~tl)~t a( v;,ryi~ lm~]lmd is to actually ~mast]re tim i~ easily (Imw I~y ]~()l(li~ sure on tim co~npressor (100 to 200 .,~(' witl~ it Jl()VVlllCler or orifice well A~otlmr type ~aking its entry into air ~lrilling is the hi,~(}~ lm'ss~re helical screw, tw()-st;U~c C()Ill])I'CSSOI', Tllis tyl~e is it i~ositix'e disl)lace~nent' oil- fl{,r~(l lubricated, co,t~l>rCssor that pro- rides a constant volu~ne at variable pressures. 'l'he sere., type compressor ~s rated at 750 to 800 ct~bic feet per ~inute at 300 psig , · A lmostcr is rcquirc(l if drilling l>~essures exceed tim j)russure capa- shot~ld be sized to handle the entire co~nl)re, ssor volu~ne being used. Oil lield boosters will increase pressure fr(un al)rn~t 300 l~si~ to al)out 1,500 l)sig and is necessary insurance should hole trouble (levoh)i). Various in- stances wl~ere a I)ooster is necessary arc disr't~sscd later. An air i):t(:kage will also include a n~isl or f()a~ u~it consisting of a 40 to 50 }~orsel)ower triplex plunger t)un~p cai)able of delivering 25 to 35 gt)~n. The l)t~mp takes suction from a 12-barrel tank that is used to ac- curately ~neasure. water injection rates. Also, an air operated (:heroical injection l)ump cai)able of injecting about 10 to 15 gpl~ is required for foaming agent (sea.i)) injection. The chemical lot]rnl~ allows accurate mca- sure~m~t of injected foa~ning agent. Fig. B illt~strates }~ow the co~npressors, booster and znist unit are t~ooked-up for an air drilling operation. A 7 to lO-inch Il) flow lint'., blooie line, carries the ctrill cuttings away frm~ the rig. 'l'lm blooie line is norm- ally 1~0 to 200 feet in length and should be well anchored, flanged and welded, ICier. 5. It is v('ry important cm~lmcti<ms--'t.5-(h,,grec or 90-degree bends--becat~se dust will cut-out the li~m m' cslahlisl~ a thin wall condition al tim be~{I. Also, I~{.ca~sc of tim pres. I,~'ss~'s t':~, },:~t tim libra. St~rMe. I~res- I'~,~,~ tim I~{~h. witl~ air ~r il' t~ex. ('(,l~)~('r('(i ;~(I al(', I)r(n~gl~t t(~ tim sur. Ih'si(l('s I)('irU~ slr;,i)..,l~l, [[a~U,,('(I, anti w('lth'd, lira I~l(~<,ie li=m I~;~s six other ~;t.j{)~' ('()[~})o~m]~ts, including: · (;;ts ()r air j('t Continued on page 106 102 Circle, 154 on Roader Service De-duster · Drill cutting sample catcher · Hook-up for a gas sniffer · Hook-up for' going to fluid dril- ling · Pilot light. Gas or air jets are used to keep gas off the rig tloor and away from per- sonnel during trips. As illustrated in Fig. 6-1oI), the jets are of two dili'er- ent designs .and sctx, c two functions. The jet at the end of the blooie line is the primary jet and is used on round trips. The secondary jet, lo- 'cated nearer the rig is used only if the primary jet fails to function prop- erly due to being cut-out by dust- 'cutting action. Also, the secondary jet is used to bleed off air pressure prior to making connections. The primary jet should be located four 1)ipe diameters from the end of the }dooie line for best results. For example, if a 7-inch blooic line is being used, the jet should be 28 inches from the end of the blooie line. Actual field measurements have shown that the primary jet will pull 6 pounds of vacuum on the blooie line. The sec- ondary jet will pull only 2 pounds of vacuum. Although it is not clearly defined, it is believed that the primary jet will safely keep 3 to 5 MMcfd gas pro- duction from the rig floor while round trips are being made. This is assum- ing the rotating rubber has been pulled. Greater volumes of gas may necessitate stripping in and out of the hole by leaving the rotating rubber in place. The de-duster is used to suppress drill cutting dust while drilling, In rcn~ote areas the de-duster is used only when the wind carries the dust in the direc- tion of t}.' rig or other equilmmnt. In I)()[)tllat('d are;ts necessary. Water (lust can be ]>ickcd ~l~ J>y llw l~t~l~ fr(~ tlw rescrw' ~,r I)un~ lilt :t~tt cir- ct~l'atc{l t~r re-t~se., 'l'lm de-(luster is easily co~slructed and installed on tim l)looie lixm. 'i't~e tlesign sl~xvn i~ Fig, 6-cc~ler, can over 100 feet l)cr I~our. A sample catcher of the type shown in Fig. (;-I~otto~n is i~stallcd on tim blooie line to catch drill cutting sam- pies. It also serves a more important function fox' drilling }mt)pie--it allows o})servation of tim dust when tim dc- duster is being used. This is necessary because, should dust disappear, damp or wet downhole conditions exist and trouble is pending or has already oc- curred. This' trouble comes in the form of downhole fires or a stuck drill string. A gas sniffer unit similar to those used in mud drilling can be i~to tim })looie li~m to detect very small gas entries (n' I)ackground gas, l:ig. 6. For convenience and case of handling, a hook-up similar to that shown in Fig. 5, can be used if it becomes necessary to use mud. A pilot light or small flame should be maintained at-the end of the blooie line. This will ignite any gas which is encountered. Two chart type prc~sure recorders are required to properly ~nonitor air pres- sure. One recorder should be on the rig floor, and a second immediately downstream of the air compressors. The rig floor chart type recorder should be a 0 to 500 psig, 12 or 24- hour pressure recorder. Thc recorder at the ai.r compressors is a part of an orifice meter run where constant pres- sure and differential are measured. This will allow easy calculation of air volume outlmt at any time, which is very important should tim air pres- sure drop or increase. For example, if an increase in air presure is not accompanied by a corresponding in- crease in air volume output, pending trouble is indicated. This trouble could be in the form of a wet or damp hole condition, gas or other hydrocarbons or improper hole clean- lng. A high-pressure Mann should bc in- stalled on the rig floor. This alarm sl~()ttltl be set to indicate any increase i~ ¢lrilli~g I~ressttre (5 lo 10 l~Sig'). A spring-loaded, dart tyim i)l;,,ccl i~,'¢liately al)ore tim Ifil I~re- vt'l/Is I}le Imck II~>xv of gas ~,' air wl,ile A I~il stol){>r }>(>tto~z~ I,~lc drill I~lltcc(I i~ :~ s;~l)I,)recl f~)[' tl~is {h):tl. A flal~lmr fyi,, tloitt I)la('etl i~ t}~, of tl~e drill string in,proves air drilling efficiency. The string tloat shortens connection . I)y t,'al)l)ing air volume and pres- ,,~rc, between it and the bottom hole tloal. 'l'l~t~s, less time is rect~ired to get this co~q)ressible ~nedium back to clrilli~g conditions. The string float, by trapl)ing air below it, keeps air n~oving around lhe bit while connec- ti(ms arc being n~ade. It is absolutely necessary to have air circulating around the bit before drilling is started, This l~revents d~ (Irilli~g and l~r()longs bit life. Because air is ('o~}l)ressil)h', a l>eriod of time is tC(lt~ircd t(> esl;tl)lish air (.irc~lation an)t~(I t}w I)it after a connection is ~ade. (lirct~lation is establislmd if there are returns coming from the blooie line or if air pressure has reached the normal drilling pressure. Drilling shotdd not begin after a con- nection until one of these two condi- tions is met. Short trips can be made to rmnove the string tloat for running deviation surveys or to keeI) the string tloat as }~igl~ in tlm string as possible. Also, more than one string float can be run if a short trip is undesirable. The float should be of sufficient ID to allow free point and back-off tools to loe run throug}~ it, should fishing operations be necessary. Thc string float can be held open to bleed off pressure by using a bar on a wire line. Also, a small hole can I), I~(,'ed in tim fiaplmr which will allow pressure to slowly bleed off. The string tloat will present no problem should tislting operations be necessary. The pit design for an air drilling op- eration should provide for a burn pit }){,l~i~d t}m standard mud drilling re- serve pit, Fig. 5. The blooie line should extend past the reserve pit and exhaust into the hum pit. This will l)rCvent a~y hydrocar})on li(luids fi'mn burning or flowing into the re- serve lilt and prevent a reserve pit tire near the rig. ~. Comln~ noxl monlh: Eli~ninaling dow~h.,h' air drilling l)roldm~s. ............. I,ITERATUItl5 CITED ~ {h,.,~i.~h,.n/ R. A, nmi I';c,J.h, J, troy blu,ly ~,. vllc~t ~,1 ,)v¢~l,md~',, {mmalh,. and mud ¢.lu,,~a ,,~...u,e ,m drllli.~ '109,1.(;, I"all Mm.I hq, AIMI'; ~ Auqrl, R. R., "V~,luuw ~as d~illinq", :l'ran,. Al MI5 ( IO5~7). ~ I',,cllm,,ml. I", II. nmi Ih'umnu, W. I~, ~ ( :J( ~'( )Wi, El )( ;M I",N' J' T ~ ~ c, wa~ takc~ I~¢,m the ~,~ 1977 I)f ~ '1'. m,,I-uy (;.M,,,v.~. }whl })y Iht I I..,fli,,.al A~o('iaf,-r'l-f Ihdti.q Contract0rl N(,w (hh:an~, l.a,, Ma~ch 16-18, 1977. Part 2 Air, mist and foam drilling:. A look at latest techniques R. A. Hook and L. W. Cooper, Amoco Production Co., and B. R. Pay'ne, E. W. Moran Drilling Co., Inc. 1 5-second summary Air requirements for air, mist and foam drilling are given and a pro- cedure for unloading and drying the hole is outlined. Some downhole drill- ing problems, such as burn offs, are unique only to air drilling, but other common difficulties may be present and even aggravated by air techni- ques. Discussed are methods devel- oped to prevent or control these ob- structions to drilling efficiency. THE SINGLE most important factor to consider in setting up an air, foam or mist drilling operation is the vol- ume of air necessary. ~~Clrcle 118 on Reader Service Care Air drilling. No upper limit has been established for air drilling re- cluircn~c;~ts---thcre is no such tliing as too much air. On the other hand, the reason air drilling fails is often in- sufficient air volulne to clean the hole efficiently ~}cl(:r a 'varied ;';.~ge of drillingS[ Aftra' air clrilli~; ow'r 3 ~illlt,~ feet of Imle witli :~l over-all :~vm'ng'e trati~m rate of I,()()0 feet l~er day i)er n)i~le is a(l.(lU;~(' t- ]c(~'l~ the hole ch'an a=~d (Irill ~'~l'i~'i{'~ly .v(,r wide r;~',, (,f ('<,~diti,,~s. 'l'l~is (;f air is I,~s('<l o,~ 7~ i~.'l~.l~-I. will r('(It~ire ]note v()l~m, w]~ile small hole sizes will rC(luirc less, A good rule AIR OR FOAM WAVY lO0 20O 30O 40O LBS. PER SQ. IN. Fig. 7 .... [J~liko tim tlrn(,(itl'~ (.;u~vo ol)tl~Ino(I (lmlnsI .Ir-du,.d drtlllnll n~ld Iho .qll{ihtly w/ivy curve obtained with loam, tho curve for tho undesirable sltl('l drilling ia highly urratlc, nit is I)~,i~,~.,r t~s~'(I is I() sl(~1) clrilli~ ~(';~s~t~'(' tim ti~e n'(l~i~'(I f~)r tim cl~lst I,, sl{)l~ m' ch'nn ~1) ;il {].' 1.1~(I ()J' tim I1~,, I.,h. sl~,~t~ltl ~)(~1 ~',.:~lly ('xceed mm A ~o()d startin~ I)oint for cl(qert~in- i~ ;fir r(:(luire~w.~)tS is based ()~ work I)y R. R, A~ll,?l,'~ !'[('(:I) in ~i~(I tl~at l}~n~) wl~;~l is ;~('l~nlly ~.,.(le(l ~() drill ,X,l<li~i~,~;~l I)~ess~,,'e is ~<'<','ss;~ry for I)l()w tile drill stri~ h)nse shm~ld a 83 tered. In some cases, 'tim addi' ' pressure can l)revent a stuck stri,.o.. Mist drilling. When formation water I)roct~ction cannc~t l)e clricd u]) or hy- (ll'()Cal'})ous are ellC()lllltCl'(N[) fO;till Of mist ch'illing is necessary. Mist drilli~g will require about 30 to 407o ~nore air than dusting and standl)ipe l)res- s~res will be greater. Mist drilling t,'esst~res range fro;~ 200 t0' 400 psig as cm~ll)arcd to 100 to 300 for dust drilling. The additional air volume and pressure are required because of the weight of the water being lifted. Foaming agents, soap and injected water requirements for mist drilling are discussed later. Mist drilling can easily become a slug drilling process if drilling pres- sure is not continuously monitored and soap and water injection volumes are not balanced to meet the existing drill- ing conditions. Fig. 7 illustrates the pressure behavior of mist and slug drilling. Pressure surges in the hole caused by heading are detrimental to bole conditions. For this reason, slug drill- ing~moving alternate columns of water and air up the hole~should be avoided as a continuous operation. Too little ~r volume is the prima~ cause of slug drilling. To conduct a proper mist drilling operation, enough air volume should be available to keep the hole Clean and continuously un- loaded. Drill .cuttings not removed fall back and bridge when connections are made. When this condition exists, one of the foll6wing should be performed: * Add more air volume * Sweep the hole with a soap slug just prior to making connection. An increase in soap concentration will create a stiffer foam that can better clean the hole and remove the heavier drill cuttings ~ Alwnys blow t]"~ hole t~nti] lhe I'pllll/i IlliSl ;t~l~l air arc ch.;,li ])ri~)r I~) Itl;tki~sg c~,t~mcli~,ss. 'l'lu'sc sit,il)lc I~r~- ~or~lod fluid drilllng. Wlw.~ the aerated Iluid drilli~g is used to reduce the density of the return fluid column and Iwdrostntic pressure on the 'for- marion by injecting air and fluid into the standpipe simultaneoUsly. Air volui~ms ~':~'d for acr;tth~ arc ~,' ~nisti~g and arc II~ougl~t of in ct~l)ic feet of air imf barrel of ~l~cl. A way Io eSli~ilte air for aeration is (lis<'t~sscd 'l']~e air volt~lne for i)rol)er aeratio~ of a fluid column can be controlled with jet subs and'by regulating air volt,me. 'l'he ideal aeratetl [lt~id con~lfines air and flt~i(l into a st;tbh', foa~n that does not ])reak down and separate until it reaches the pits the surface. Air must break out at the surface prior to reaching the ~nud pumps. UNLOADING AND DRYING THE HOLE The proven'method, for unloading the hole of fluid, drying it and start- ing air 'dust drilling is as follows: · Run thc drill string COml)lete with desired bottom hole assembly anti bit to bottom. · Start mud pure1) and run as slow as Imssible. Pt,nll~ fluid at a rate of 1/~ to 2 barrels per minute to reduce fluid friction pressures to a minimum and to pump at minimum standpipe pressure for circulation. Standard fluid hydraulic calculations will indicate what the standpipe pressure should be at 1/~ to 2 bpm. · Bring one con~prcssor and booster on linc, to aerate fluid being pumped down thc hole. About 100 to 150 scfm per barrel of fluid should be sufficient for aeration. If too much air volume is being used, standpipe pressure will exceed the pressure rating of the compressor and/or bo~ter. Therefore, slow thc compressor down until air is being injected and mixed with the fluid going down hole. Also, the mist pump and soap in- jection in~l> sl~m~ld l~c injccti~g a~tl 3 i,.l~l~., r,'al.'~'llvoly. '1'1~' will li~, linc II,~itl ;~l ;~ir I~q,,~'ll,'r ;t~l lii,,l~tc~,'~l, sta~tllfilW l,'Csst~rc will tl~e fluid colu~,~ ;~tl u~load ti,'. Thc aeration procethtrc Js far pcrior wlwn coral)areal to tim slt~g ~net}~o(1 of t~loarli~g the }~ole. slug method is accomplished by pump- 4 altt'r=mtc sltigs ()f water and air (l(,w~! tllc Imlc ~sntil air can be usecl ('~,lti~m,isly. Air is first injected t~l to a~ arhitrary maximum l)ressure, tl~c~ 'walcr is i~Ljccl('(I to lower the i)n'ss~rc t,) ~()~lc arl)itrary i)rcssure. 'l'llis I)r()cedtlre is relocated ~til air can be injected conti~uously. l lt~wcvcr, thc aeration ln'ocedure re- (it~ircs less ti~m, does not cause s,~ry, i~sg of tim hole due lo lieading, <l,,,.s ,mt ('~tt m,t l)it walls sturges are eli~inatcd and can bc done generally at lower operating px'essures. * When the hole is unloaded, the mist and soap injection l)mnl)S should remain in operation. This provides a mist (1/2 barrel of water per hour per inch of hole diameter and /2 to 4 gallons of soap per hour) which can clean the hole of sloughing for- mations. * At tl~is i)oi~t drilling using air or n~ist can co=~en(:e. ])rill 20 to 100 feet to allow any sloughing hole to be cleaned up. e After the ]~ole has stabilized (no slox~gl~iz~g), stop drilling and blow the hole wit}x air inist to clean the hole of drill cuttings. About 15 to ~0 min- utes is sufficient or until the air mist is clean. Clean air mist is usually a fine spray and whit~ in color. e Put the kelly back on and set the bit on bottom. Since the hole is now full of air, the soap and water will run to bottoz~. A proper soap sweep cannot be achieved unless it is mixed with air and pumped tip the annulus. This cannot be done if the drill bit is above the soap and water.. * With the bit directly on bottom, start air down the hole. Pump straight nit at normal drilling volumes until tl~e soal) sweep comes to the surface. q'he soap will appear at the end the blooie line and look like shaving o (',(.~li~l~(' I~) I~]~xv IIH' ],ftc wil]l ~() I'~'~'1 ;irc rC~lt~ircd f~n' (ltssl Io nl~l~ear I1' I}w, llt~h' tl(w,s ll()l tlllsl after this i~r~ccclure llas been followed, pump a~mllmr SOal) slt~g arot~n(1. 'If a clustlng co~(li~im~ ('anll()l be achieved, mist drilling Illay be ~lecessary. W~')gll") (")11 · Mnv 1977 Depending on the depth, this cfdure from start to dusting reqmres about 2 to 6 hours. Iloles have been unloaded using the aeration method from {lel~ths of over 11,000 l'eet. Also, a well can be dusted, mist drilled, dried up and returned to dust drilling. The key to drying a hole is have it clean. In some cases, drying agents have been tried with little success. To date, the best drying agent available is in the hole below the drill bit. Formation · is an excellent drying material. UNDERGAGE BITS As mentioned in Part 1, out of gage bits are a serious problem. Those that offer the most gage protection are used to achieve longer bit life and minimize reaming long sections of hole. Over-sized insert air bits can eliminate reaming and pinched bits. For example, an 8-inch mining type air bit can be run first, pulled as much as ¼-inch out of gage and still be followed by 7~-inch .bit without any risk of a pinched condition. Ball and roller, non-sealed bits, not specifically designed for air drilling, will pack dust (drill cuttings) in the bearings and lock the cones. For this reason this type is not desirable for air dust drilling. However, the non-sealed bit can be used when air misting. Other types such as journal or sealed bearing bits have been used with sat- isfactory results in all air drilling op- erations. One of the most common mistakes is starting to drill as soon as the bit hits bottom. It is vital to establish air flow before drilling so that initial cutting build-up is prevented and bearings are kept cool .and clean. HOLE DEVIATION Hole deviation can be a serious problem in any drilling operation, but it can be controlled in most air-drilled holes tllrm~gh tim ~s(: a~(l pr(q)cr ap- Plicatlon of two basic in'i~,cilflCs. 'l'}mse pri n c il) lcs are the i)cmlulum ell'cot and tim i)acked or stiff hole assembly. The tools necessary to effectively carry out either of these two prin- cip]es include: · Square drill collar · Reamers~string and near bit · Stabilizers with tungsten carbide insert replaceable wear pads · Air percussion hammers · Large diameter round drill collam 1 1 Fig. 8~Bottomhole assemblies used for deviation control in air drilling opera- tions: 1-round drill collar, 2-square drill collar, 3-reamer, 4-stabilizer with replaco- able woar pads, 5-short squaro drill col- lar, 6-jot sub, 7-air porcusslon hnmmor. 'l'ln' i~ackcrl m' still' ]~oh, drillJ,lg assc~nbly, found most effective in air drilling, slm~kl be ~seti lo eliminate or ~ni~imize doglegs. If {h'illing off linc lease is not a l~roblmn, t}m }role shot,Id be allowed to deviate. 21'}~is }~as pro- vided the lowest cost holes possible when air drilling wells from 8,000 to 10,000 feet TD. On the otlwr hand, deviation should be controlled in the upper part of the hole when drilling deeper air holes. ,oglegs in the upper hole create ex- (:cssive drag and excessive wear on drill pipe and tool joints. Tills is espe- cially tr~m as tl~c wc. ll is drilled deeper. lhe square drill collar, with its in- hermit higlier rigidity, provides three advantages: I. l')cvialion control (sq~mre collam add 60% ~lore strength than round collars and help avoid dogtegging) 2. A reaming ell'cot 'behind the bit 3. Indication of bit OD wear. Square collars are 1 / 16-inch smaller on diagonal titan the bit gage so that any unusual torque build-up will alert a driller to possible bit gage wear. Square collars will inherently wear at the bottom and top. T0 minimize this wear, tungsten carbide inserts or tungsten carbide pads have been placed in these areas. Tl~cse inserts or pads, 12 to 18 inches in length, extend the usable life of the square collar. $lobilizers witl~ tu~gsten carbide in- sert replaceable wear pads are essen- tially short squarc collars. The advan- tage to this tool is that the pads can be replaced in the field. ~ir hnmmer. An excellent tool, proven to control severe deviation and maintain a straight hole; is the air per- cussion hammer. It is used to main- tain a straight hole and achieve a rea- sonable penetration ratc while running light weight (1,000 to 5,000 pounds) on the bit. The air }~amt'ner is used in conjunction with the pendtllum effect. To acco~nplish this, a stabilizer usually is run 60 feet above the bit. The reamer placement will depend on the size of the drill collar being used. The reason for this is that a greater pendu- lum effect or lateral force on the bit can be achieved dtm to lhe stiffness of tlw various sized drill collars. When an air ha~nmer is used, there arc several tecl~niques which should im'.w.~l i~l~?,l[i~g I}~c air i~,ox,c all rt~st a~<l flakes fro~u inside ~-i~tcr~mlly coated drill pipe by rattling tl~c drill ifilm and dope tim l,i~ c~(I, not Ibc I)ox, wl~cn running (lrill c~:llars a~(1 drill ifilm. To In'event the air l~a~u~ier h'mn scrc. w('(I wl~ile g~)i~g i~ tim ]lole, make each con,motion up drill collar tight. Also, the air hammer should be testc(I on tim rig floor using thc air w)l~m(', normally ilscrl for drilling, Note tJ~e pressure at which the air hammer operates at the normal drill- 'ing air volume. This will Mlo%~a_.ny malfunction in the operation e · hah)mcr to be detected while d .... Air hammer operation should be checked periodically--stop drilling, leave weight on the bit and air on hole, place a steel object against the kelly and near the ear and listen. A faint buzzing sound will be heard if the air hmnmer is working properly. Air hammer manufacturers recom- mend pouring a small amount of oil down the drill pipe periodically to lu'bricate the moving parts of the hammer. With proper care and han- dling, an air hammer can run 150 to 300 hours. Bottomhole drilling .assemblies used to control deviation in air drilling are shown in Fig. 8. DRILL STRING WEAR Drill pipe and collar wear in air- drilled holes does not appear excessive and may even be less than wear in mud drilled holes. For example, one string of pipe has been in continuous air drilling service for 1/= years with over 380,000 feet of cumulative hole, and annular air velocities have been 9,000 FPM. This string of 4/=-inch, 16.60 ppf, Grade E, X-hole drill pipe reflects a minimum wear of 0.067 inch (20%) loss of tube wall thickness, 0.53 inch (9%) loss of tool joint OD, and 0.31 inch (57%) loss of shoulder width. A periodic inspection of drill pipe is good drilling practice because drill pipe failure in an air hole can result in a junked hole. The inspection of this string of drill pipe reve~aled that 297 joints (91%) of 327 joints were still premium pipe. Ten joints were rejected due to thin average wall thickness. This particular string of drill pipe was internally coated and hard-banded Another drill pipe string is known to have I>een in cc)~ti~tm~s air clrJlling ~,lwr;~li,,~} for f~,,'c I,,i~,g n,l~h,'~,~l, ~, II,,,xililt,,,~ ('xallll)l(' (,f (I,'ill Ix~i~t ot~t II,at nit {Irilli~ig is ,,~t exccs- sivcl)' d:t~,~agi~g I,'eca~,lio,~s and l,;u~clli~g tecl~,~iqtms are Evicle~x:e has slmWn tl~at drill pipe crosioll (';111 ()(;(:tlr band and tim tool joint ~lmtal xvhc,i the box end is hard-'banded. This ero- sion is due to drill trotting boinbarcl- ment similar to smxl blasting. This type erosion can affect the life of a.~.of formation wedged between the hole joint of drill pipr'. .nd drill string or when excessive dog- I)esign work for drill pipe to b~ legging exists. used for air drilling has not kept l~ace with other advances in technology. ]~ossibly, if hard-banded drill pipe is desirable, the hard I)and should bc put o,~ thc pin end rather than thc box thereby minimizing tool joint wear due to erosion at the hard band-tool joint interface. But this may require longer tool joints. Excessive wear on a square collar can cause deviation problems due to changes in 'bending and stabilization characteristics. Therefore, a square collar should not be allovced to.wear excessively before it is replaced. The fact that a square drill collar was used ahead of the previously men- tioned, long Wearing drill pipe helps explain' its exceptional performance. Square. drill collars rninimize doglegs and doglegs wear drill pipe, partic- ularly when they are in a sharp, abra- sive sand. ' SUPERVISION IS IMPORTANT Air. drilling in any form requires 24-hour supervision because trouble can occur quickly and compound so fast that air drilling economics are lost and expensive fishing operations result. Avoiding problems and expensive fishing operations can be accomplished through proper supervision and ap- plication of proven air drilling tech- niques. For example, to avoid run- ning bit cones off, bit torque should be monitored continuously. Checking hole torctue off bottom and bit torque on bottom will provide an accurate measure of a bit's.ability to turn properly. Insufficient air volume to clean the hole can result in stuck drill strings. ']"}~is problem is most likely to occur wt~ile n~ist drilling or wlmn slm~ghing air ]()~;, I() 3(}~;, great('r tlla~l iii Ill,itl f~ril,'r c(,~l)~)~xh Illcse (lead loads. AI),~()n)ml l)OSsible sign ()f lx~ndiag troulfle sucl~ as a sl~l('k ()~' i)art(.xl (I,'ill s(ring. '.I'}~is lyl)c drag o(;(ua's wlmn tlm I~ole is'not being cleaned and cutting load is M,ilding t~p, wlmn a sloughing hole condition is l)resent witl~ large c]~m~ks STUCK PIPE Wl~en an al)hernial drag condition cxlsts, il is possible that the drill string will bec(mm stuck. To prevent the (trill string frown sticking, due to pull- ing into and packing dry drill cuttings, never pull on the string without air circulation. The air will keel) the cut- tings moving and allow them to work past the drill string. Should the drill string become stuck, excesive pulling usually will not help free the pipe. A good proven practice is to blow the pipe free with nitrogen under high pressure. This is easily accoml)lishecl with liquid nitrogen available for oil field use. But, this procedure will work only if the drill string has not been pulled excessively and the cuttings packed tight. Hole drag and torque can be mini- mized by using graphite for lubrica- tion. I3~ chemical injectors are used to inject graphite directly into the air stream. A hole occurring in the drill string while drilling, is a ve~ dangerous con- dition and is noted by a drop in stand- pipe t)ressure. When this ~curs, stop drilling and set 4might on the bit. I,eaving bottmn wifi~ a partially-parted drill string may result in expensive tishing operations or a junked hole. There is little chance to recover the dropped pipe due to corkscrewing and breaking of the drill string. Also, any attempt to try to part the drill string with the bit on bottom can pro-- duce the same results as dropping the string. A proven procedure is to set the bit on bottom, l(~.ate the hole by reverse circulating and running a horizontal sl)inner s~rvey. By knowing the exact (Icl)Ih of t}l(' ]~ole, tim drill string can 1,, scl i~ a ~(,~l~';~l wcig}~t i)i~silioz= and WATER ENTRY ," W:,,,',' ,',,,,'y i,,,,, ,I,,' },,,I,, is a ,,,ajor :,;~ ~d' wet~,'ss ra~cs I'r~,~ (I;t~l~ Io water fh~ws. I);t~l~l~ or Imrlial]Y wet condi- ]~ lion,s can Ix: dried up by usin~ soap slt)gs ~c.)~tion('(I earlier. As long as a c()nlint~(x~s drilli~g ol)cratio~ exists, : t}m ]~.ole sl,mhl re~)~ain relatively d~. /. 86 Circle 119 on Reader Service However. after each trip, the hol-~-may have to be redried. Large water flows may require aera- tion for air drilling to continue. Should a water flow be encountered, indi'cated by increase in standpipe presst,re and loss of drill string weight, the drill string should be pulled immediately, under certain conditions, to prevent sticking caused by sloughing, water sensitive shales when the formation water is relatively fresh. Many materials such as cement, plastics and chemicals are capable of shutting off water, but the difficulty is in the proper evaluation of the water producing zone and the ultimate ability to place the shut-off material where needed. Readjusting the casing pro- grams, to fit air requirements is the answer to water problems in many areas. When a hole makes water and it cannot be dried, .mist or foam drilling should proceed by injecting a foaming agent into the air stream. A good foaming agent, soap, which generates a stable foam with enough film strength to' keep the hole clean and relatively free of produced water should be used. A good rule of thumb is to inject 1~ barrels of water .per hour per inch of hole diameter plus /2 gallon to 6 gal- lons of soap per hour. Soap should be injected with a separate injection pump. The volume of soap should be kept at a minimum value sufficient to clean the hole. An increase in soap concentration gives the foam more stability and increases its carrying capacity. Mist injection water should inhibit shales and the pH should be alkaline. In some instances, corrosion inhibitor should be used. Depending upon con- ditions, particularly the volume of water flowing into the well, soap con- centration may need to be changed. If insufficient soap is used, there will be considerable heading. If too much S{ml~ is t~s{',tl, tim well will Im:ul wilh slugs of Ileavy foan~ a~ld no li{lt~id dis- cltargc. Tim lowest conce~t,'atlon of soal~ that gives a stendy flow from the blooie line and a steady standpipe pressure is the amount desired. DOWNHOLE FIRES AND EXPLOSIONS When gas is encountered during air drilling, the first two conditions of the three necessary to create a fire (fuel, 88 400 ~"'~NFLAMMABLE AREA' :~ ": "~' '~"' ', EFFECT , ~;~;~;~;~/OF PRESSURE ;,~Sg: / upou ,.[ ;i~:: 'J:~;:Sff'_~ I OF INFLAMMABILITY :~¢t: .~t~ir.~ OF PITTSBURGH 360 320 280 240 200 160 120 8O 40, 0 0 8 16 24 32 40 NATURAL GAS IN MIXTURE, % BY VOLUME Fig. 9--Downhole fires or explosions can occur even with Iow percentages of natural gas present during air drilling when a pressure chamber is formed by a mud ring. oxygen and ignition) are present. Thus, the ~nain concern, when gas is encountered while drilling with air, is to prevent' ignition. Three things will cause ignition during an air drilling operation, namely: · A mud ring (seal between bore hole and drill string · Downhole sparks · Small hole in the drill string. Mud rings are the primary cause of ignition, causing downhole fires or burn-offs. Ignition will occur, with proper fuel to air ratio, when a seal around the drilling assembly is formed. This seal is in the form of a mud ring created by drill cuttings and moisture. Wlmn tim mu(I ring is fornmd, air cir- si]ni.lar to tl~e ig~ition ('l~a~l)('r i~) a (ti('s{'l e~gine, lgt)itiot) then ~;curs in this chamber when the gas to air ratio is in the 5% to 15% range, Fig. 92 Tlmrefore, by sealing off the air circu- lation a~d m~ricl~ing tim gas ~ixturc, burn-off can occur with very small gas entries. Experience from several downbole fires indicates that most burn-offs cc- cur in the drill collar string. Also, most burn-offs occur at the top of the gas entry zone. In ahnost every case, at tim time of a burn-off, the drill string bas been stuck, indicating the presence of a ]~ud ring. The two other sources of ignition for which there is little or no control while dust drilling are downhole sparks and small holes in the drill string. When drilling hard quartzite sands, sparks are caused when tungsten car- bide bit inser:s, drill collars and drill pipe tool joints strike the hard face of the bore hole. These sparks are a source of ignition in the proper fuel to air mixture. The other source of ignition is a small pinpoint hole which can develop in a drill string. It has 'been demon- strated that when air (200 to 400 psig) is flowed through a pinpoint size hole that friction across this hole creates enoug'a heat to cause a hot spot. This hot spot can aid ignition of the righ: air-gas mixture. f)ownhole lires and explosion cause extensive damage to the downhole equipment. Drill collars and pipe are melted and slag has been blown up- hole several hundred feet. Even though downhole equipment is damaged or destroyed, there is no damage to sur- face equipment. Most of the time, the only surface indication is a stuck string and a surface recording temperature survey may have to be run through drill string to determine if a fire oc- curred. Because of damages to downhole equipment after a burn-off, fishing operations are difficult and sidetrack operations are usually necessary to drill deeper. This operation is expen- sive and tithe consuming, thus, the prevention of a downhole fire or ex- plosion is of l~rit~mry importance. Provontlng downholo tiros. 'l'lmre are two l)ositive ~mtl~(~.ls to prevent (h,w~l~,)h: fires. 'l'lm Iirst is to drill wit}~ tlt~icl, but tills ~nctl~od is n~uch too expensive and slow for marginal gas plays. Tl~e second metb~ is to drill l>ote~tial pay zmms with gas, also ex- pe~sive at today's gas prices. From a practicnl standpoint, a well could be air drilled to top of potential 't ;4' gas pay zones, then gas drilled through ..!.~ the pay. However, gas is not always . Circle 121 on Reader Service Card available and drilling every potentia gas pay with gas c. an be expensive an, will be more so as the price of natural gas increases. At present, mist drilling is the most common method used in preventing a burn-off when gas is en- countered. There may be no ab.solute method to prevent a downhole fire while drill- lng with air, but certain mea~sures can be taken to lessen the chance of a burn-off. Constant supervision is an absolute necessity in any air drilling operation. Pressure recorders with high pressure alarms able to sense .5 to 10 psig increases in standpipe pressure are 'necessary. The pressure recorder denotes the formation of a mud ring or back pressure from gas entry through pressure increase on the standpipe. When a ga.s show or an increase in standpipe pressure is noted, several steps must be taken to prevent a burn- off. These steps are' 1. Immediately stop drilling 2. Shut air off and monitor gas flare A. If gas flare sustains, determine whether or not gas is wet by noting: a. Wetness of cuttings at sample catcher b. Black smoke and/or yellow color of burning gas, indicating distillate in gas c. Sparks at end of blooie line, indicating drill cuttings are damp with distillate B. If gas flare will r~ot sustain or burn with air off proceed to step :3. 3. Put air back on the hole and deter- ~nine if gas is wet A. Do not drill at this time, ;~s new ~:uttings may form mud ring !1, Will~ air in'tyrant tim l'tn'~mti~n~ of a IIIIItI ring 4.. If gas is wet (water or distillate) as indic, atcd i~ 2-A, 2-1~ or 3, ~nist drill or drill witl~ gas 5. If gas is dry, or no sparks, no black smok% or ~o wet sa~nl)les at surface A. Drill 5 to 10 feet B. Pass tool jOints to avoid pressure increase by mud rings C. Continue to drill at 5 to 10 feet intervals until it is determined that a wet gas condition does not exist Dt~ring all these steps, while air is on the hole, monitor standpipe pres- sure constantly. As long as standpipe prcss~lre is above normal drilling pres- sure, the prospects of a burn-off are good when' gas is encountered. Re- member, i: takes only a very small amount of gas to ignite a burn-off when a mud ring is present. Partial mud ring or closure in the' annular space restricts air flow causing standpipe pressure to increase. Com- plete closure can occur quickly and will not be noted immediately at the surface due to the compressibility of air. For this reason, quick action is necessary to prevent a burn-off which · starts with stol) drilling. Assuming that drilling is not stopped when a gas show or pressure increase is noted, the following events will OCCUF: · A small increase in standpipe pressure occurs · Drill cuttings become damp due to distillate or water and will begin to pack together to' form a mud ring around the drill string · As the mt~d ring closes, pressure will further increase to the operating capacity of the compressor · The drill string will .stick, indi- cating a mud ring has formed · Ignition of a downhole fire then occtlrs. Based on field experience of actual downhole tires, it requires no more than 4.0 feet of drill cuttings to gcn- Pr;liP (:l~¢H~gll (l~sl I~ create a nnKl ring I.I'I'I,;ItATI I It I~ (;ITEl) ~ Cunni,~gham, R. A. and Eeuink, J. G.. logy.allldy o~ elhqt o[ overburden., formation,, , and md column I}rCssure on (Irllhng rate, ] aD ,r HfH-G, Fall Meeling, ~IME,, lima,nm,. 195~. a Anrcl, R R., "V* h [ ,' ~cqmrcmrnll Ior itlr or d illinr" 'l'ran~. AIME (1957). . ~',,eltm:um' ~ 1: II. m.I Br~mnn, W, 1~,t ,,f ,I,'illin~ ~' ..... Is' rrd ..... d I,v air rejection," %V(IIII.II (111., Aug. 1, 1955. . · , ~ Jtcprinled frnm iturenu of Min~ Rel}ort ol ~n- w,,t{ffali{m~ 37911, ACKNOWI.EI)(;MENT 'l'lii~ article wa.~ Ii}ken btm) the paper, "Air. gas a,,I foam d~illin~ lec/mitlm'S,' Ihe authors incscnted to the 1977 1)~ lln~ Tcch ~o o~y Con- h. rcnce hchl by the International Association ol Drilling Comracton in New Orleans, La.. March 11¢ 18. 1977. ~lrelo 1~3 on ~aader Somlco Oard~' AIR, GAS AHD FOAM DRILLIHG TECttliIQUES ,. BY MR. R. A. HOOK, A~IOCO PRODUCTION CO[.iPAIiY, MR. L. W. COOPER, AMOCO PRODUCTION COMPAF~Y,. and MR. B. R. PAYNE, 'E. W. MORAN DRILLIi/G COMPA[iY~ II'~CORPORATED AIR, GAS AND FOAM DRILLItlG TECttNI(/UES BY FIR. R. A. ttOOK, AMOCO PRODUCTION COMPAIiY, MR. L. W. COOPER, AMOCO PRODUCTION COI.1I~A.qY, and MR. B. R, PAYHE, E. ti. MORAN DRILLII'IG COMPANY, II,ICORPORATED · . INTRODUCTION The'use of air or gas as a circulating medium was introduced in the earlb< 1950's. Even though initial attempts'were crude, significant increases in penetration rate and bit life were obtained. Since these initial attempts, development of air and gas drilling techniques have expanded and are widely accepted today as a method to reduce drilling times and cut cost of many wells. Along with the time and resultant dollar savings, other advantages such as immediate and continuous hydrocarbon detection, I~il~imuln dalnage liquid sensitive pay zones, better control of lost circulation, and cleaner .. cores are obtained. .. Today's air drilling tecl]nology is attributed to many drilling people whose initiative and accumulative experience have refined the method and deternlined situations where the technique is most applicable. The lack of undersbanding, rather than experience, is often the reason for not accepting air drilling. ' Drilling with air does 'i~volve special conside~'at'io~ in Lt~e ~.se of [~(itiil~lnellt and drilling techniques I:t~at are not commonly e~c:ounte~'e~l w~th ol.~er d~'illi~g media. For exan~ple, air, unlike flexi,Is, coml),'.,.-~es, ~..~., rea~lily a~(I ~'(,.q~l~res a somewhat more sophisticated engineering approach to acl~eve t~e desired results. This paper discusses the mechanics of air drilling, modifications such as ,list or foam drilling, unique equipment requirements, and downhole problems that have been encountered. Special attention is given to presenting techniques developed to prevent or control downhole problemS. · DISCUSSION Mechanics of Air Drilling Air is the ultimate low density drilling media. In order to achieve optimum results and greatest economy from air drilling, there are several factors which should be considered. Hard formations which are dry or produce re- latively few formation liquids provide the best results while air drilling. When the .formation is completely dry~ or tl~e influx of liq~ids.is slight enough to be absorbed in the air stream, the drill cuttings return to the surface in the form of dust. Also, this allows for immediate and continuous evaluation of hydrocarbons. Other proven advantages for the use of air are' (1) low cost, (2) increased penetration rate, (3) longer bit life, (4-) better control in cavernous and lost circulation areas, and (5) minimum damage to liquid sensitive pay zones. The fact that the drill string will always, be on bottom wt~en gas is encountered is a big advantage in well control. If the hole is gas Free wl~e~ a trip is made, it will be gas free when the new bit is returi~ed Lo bottom. Mud-filled holes will sometJlnes allow gas to unknowi~lgly enter tile wellbore oll trips, dtle to reduced hydrostal:ic t)~'essu,'e, and create well cont.~'ol I)~'ot~len~s. Gas already penetrated <t~lring air (trilli~lg ot)el'ations will e~t(;r tll(~ wellt~o~'e on trips; however, this gas is always a known quantity and can easily be jetted away fronl the rig and operating personnel by using jets on the blooie line. · This jetting'procedure and operation ~.Jill be discussed later. · The biggest enemy air drilling has is large, water-bearing formations. The rate of 'Formation waLc, r influx which can be ~la~lle(I 'is n~: ~lc'Fin~:d. Wt~r.,~ water is encountered, mist (foam), aerated or slug drilling can be used. Mist drilling can handle up to about 200 barrels per hour w~l:er influx. When surface pressures exceed the limit of the air compressor equil)~?~ent, aerated or slug drilling can accommodate larger volumes of water. Other disadvantages to air drilling are: (1) downhole fires and explosions are possible, (2) sloughing of formations (When dry or wet), and (3) soft formatioHs. These disadvantages will reduce the efficiency of' air drilling; howeVer, with air equipment available today, they can be handled. Increased penetration rate is among the first benefits ~oticed when air is used as a circulating medium.. This increased penetration rate is clue to the low density of air or gas which minimizes hydrostatic t)ressure and aids fracturing at all. times. The effect of fluid column pressure o~ pene- tration is illustrated in Figure 1.1 Differential pressure in this examt]l'e is the difference between fluid column pressure and pore fluid pressure using drilling mud. ActUal rock removal or cutting is done by subjecting the rock to compressive loads greater than its ultimate strengtt~. As the bits rotates, the rock is · caused to fail or fracture under this dynanlic loading. Crushed formation or chips literally explode off bottom and are swept into the a-ir stream and are carried to the surface. This explosion or rapid mariner in which cl~ips are removed from bottom is a result of maximum differential l~ressure into the wel lbore.. . o Chips which are removed-from the bottom exist in a range of sizes from fine to coarse. As 'these particles start up the annulus, the larger sizes are ground and pulverized by the drill string. Also', the high velocity forces the cuttings to collide with each other, the tool joints, and the wall of the hole. These actions reduce tt~e drill cutting sizes to the s~na'll dust-- like particles seen at the surface. Routing drNll-off tests can be run to obtain the optimum I)eneLraLion rate. It is suggested, because of the faster penetration rates with air, that a drill-off test be conducted over at least 60 feet. That is, apply the same weight on the bit and rotary speed over 60 feet and average the penetration rate. Then change either W.O.B. or R.P.M. and repeat the process. This procedure averages out thin formation changes and will provide the optimum penetration rate. Bit performance is an important factor in any drilling ot~eration. In air drilling, select the bit with the best gauge protection. This will, in some cases, ne'~,'(.c..,si t. aI;(? counL'ing and COl~tl-~nt'i~g t.l~e otll.(~' ~-c)w oF i~,.;e~'t.s c~r teeth. The bit with tl~e most outer row insert~:, or t(~et:l~, v~'i'll give ti~e best performance by holding its gauge longer. One of the detriments 'in air drilling is bits going out of gat~go, l'his problem is most prevalent when hard, abrasive quartzite sands are drilled. Reaming behind an out'of-gauge bit causes Premature bearing failure of tile bit being used to r'eam. This is caused by a ~inched bit when the bit reaches bottom after reaming. Premature bearing failure shortens bit life and neces- sitates the use of more bits per. well. Hard formation insert type bits are used in most air drilling operations. Today's market offers bits made for air drilling. Some of these bits, however, are manufactured for mining operations. These mining bits have outside dia- meters which range from - zero to + ¼"; i.e., a 7-7/8" bit could be no smaller than 7-7/8" but could be as large as 8-1/8''. Also, some bits are manufactured for oilfield air drilling. These bits have outside diameter specifications which are tile same as bits normally used to drill with mud. i~hen an air bit is used, experience has shown that bit life and penetration rate· can be improved by blanking one jet nozzle. When a blank is used in a jet nozzle, the blank.should go between the cones with the most gauge inserts (see .Figure 2). Tile reason for this is that the cones oil each side of tile blank will bear most of the cutting load while drilling. Therefore, these . · cones should have tile most inserts and best gauge protection. LInder normal conditions, the other two open jets should be left ope'n or jetted with 20/32" or 24/32" jets. The blank jet, in an air bit, improves bit life because tile blaiIk restricts air flow through the jet llozzles. This increases tt~e back pressure at ttle bit and forces more air th~-ough tile air tubes and across the bearings. This keeps tile bearings cooler and cleaner and will extend bit life. '[t~e pre'.tsure increase, due to blankil~g oi~e bit jet, is about 10 to 15 psig. ,. The second advantage to a blank jet is better hole cleaning, noted in most 'cases by faster penetration. The blank jet forces tt~e air to flow'across the bit face~ thereby removing cuttings from the center of the bit and t~reventing any regrinding of cuttings which would be trapped under the bi C. Symmetrical jetting can, under certain conditions, build-up cuttings in tl:e bit ce~lter. Effects vary with various formations; however, possible advantages t~ave to be weighed against negatives, such as reduced bit-bearing cooling. Equipment Required for Air Drilling Conversion of a conventional rotary rig to an air drilling operation is a simple matter. Most of the liquid and solids handling equipment, normally used for mud drilling, can be removed. For an air drilling operation, the .liquid handling equipment should consist of one mud pump, a centrifugal transfer pump and about 1,500 barrels of water storage (steel mud pits can be used for water storage). A valve manifold is welded to the standpipe on the rig floor (see Figure 3). The hardware, valves, and lines in tt~is manifold sl~ould [)e sized ai~(l pi'es- sure' rated to provide minimum friCtion losses and nlaximunl ol~eratinrj pressures. A rotating dr"illilltl tl~;,id (l"otaLit~g blowout l~l'~:v~:l~Let')'i'.; ~:',t~ lll.'i,~l Figure 4). l'l~e totalling head maintaii~s a co~stal~C seal ,~'u~l~l all elements in the drill string except large diameter' pieces s~ct~ as larue dri 11 col 1 ars, reamers and dril I bi t. l'he rubber seal u~i L wi 1 1 seal ,, around any shape (kelly or dr~ill pipe). This packing elemen-t rotates with the drill string. This allows the drill cutting or dust to be directed out ..the flanged outlet ai~d ay~ay from the rig via "blooie line." Proper alig~lnerlt of tt~e'rotating head is essential. Tt~is will save time on connections a~/d prevent undue wear on the A'method for proper alignment.of the rotating head is to set a drill collar on the slips in the rotary table and center the drill collar in the rotating head. Centering can be done by using a steel tape line and measuring from the inside diameter of the rotating head to the outside diameter of the drill collar. CorreCtions in alignment can be made with chains and boomers. ~,lhen the 'rotating head is properly aligned and centered, braces can be attached to the head and to the substructure. Welding these braces will prevent movement and misalignment during drilling operations. The'life of the rubber element in the rotating head can be extended by keeping the kelly well lubr.icated while drilling. This is easily done by pouring water and/or liqUid soap on top of the rubber element after each connection. Oil can be used for kelly lubrication; however, oil tends to pack cuttings in the rotating head whict~ can restrict a'ir flow. Oti~er blow-out control equipment is no different from tl~at n(-)r,nally used for n~ud drilling. A double ram BOP stack sized to meet anticipated press~re requiren~ents is sufficient. .., For today's air drilling operations, air compressors are available wl~ich provide adequate air volumes along with pol'tability. Tl~e most conlmonly used oilfield air conlpressol' is a positive displacement, double actinet, i, recip- rocating, two or three-stage type conlpressor. This type compressor offers a Wide flange of sizes and pre~ Are .ratings necessary for an ef'ficie~t drilling operation. Also, th.is type co~nl)ressor has been designed For continuous operation. , number of compressors in a package will depend on tt~e air volulne recluired to drill .the hole efficiently. Generally, one air compressor, available on today's market, for oilfield drilling will put out from ilO0 to 1200 cubic feet of air per minute at 300 to 320 psig maximum pressure. The positive displacement type air con~pressor is rated accor~ting to piston size and the output is dependent upon the altitude at wl~ich the compressor will operate. The compressor manufacturers can provide data on volume output at varying operating pressures. However, a sure way to know what air volume is being pumped is to actually measure the air output at drilling pressures. l'his is easily done by holding back pressure on the compressor (100 to 200 psig) and measuring the output volume with a flow meter or orifice well tester. This is the only way to be sure of the actual-volunle bein!l delivered to the bit, ' AnOther type compressor which is making its entry into air drilling is the high pressure helical screw, two-stage conipressor. TIiis type compressor is a positive displacement, oilflood lubricated, type compressor which provides a constant volume at variable pressures. The screw-type compressor is rated at 750 to 800 cubic feet per minute at 300 psig. A booster is required if drilling Pressures exceed the press'ure capabilities of the compressors. The booster should be sized to handle all the compressor volume being used. .'File oilfield booster will iiIcrease pre'.~s~re From about 300 psig to about ]500 psig. The booster is necessary insurance on an air drilling operation shoul'd hole t~ouble develop. The various instances where a is necessary are d'isct~m,.;ed under "Air Re(lt:irement5" Other equipment necessary in an air package for an air drilling operation is a mist or foam unit. This unit consists of a 40 to 50 horsepower triplex plunger pump capable of delivering 25 to 35 GPM. The tripl.ex pump takes suction from a 12-barrel tank which is used to accurately measure water injection rate. Also, an air operated chemical injection pump capable of an injection rate of about 10 to 15 gallons per hour is required for foaming agent (soap) injection. The chemical pump allows accurate mea~urentent of injected foaming agent. Figure 5 illustrates how the compressors, booster and mist unit are hooked-up for an air drilling operation' A 7 to 10 inch ID flow tine, "BLOOIE LINE", carries the drill cuttings, "DUST", away from the rig. The blooie line is normally 150 to 200 feet length and should be well anchored, flanged, and welded (see Figure 6). It is very important that the blooie line have no angled connections; i.e., 45o or 90o bends. Any angled connection in the blooie line is da~gerous because dust will cut-out the line or establish a thin wall condition at the'bend. Also, because of the I)ressure drop around these bends, surge t)ressures can part the line. These surge pressures occur wl/ile unloading liq~i(I from tile hole wittl air or if unexpected formation liquids are encountered a~d are surface by the air. Besides being straight, flanged, and welded, the. blooie line has six other major components. These components are: (1) a gas or air jet, (2) a de- duster, (3) a drill c~ltting sample catcller, (4) a t~ook-~p for a gas sniffer, (5) a hook-up for going to fluid drilling, and (6) a pilot light. IU The gas or air jets are used to keep gas off of the rig floor and away from rig operating personnel during trips. .As illustrated in F'i!]~re 7, I:lle jets are of two different designs and serve two functions. Tt~e jet at the end of the blooie line is the primary jet and is used on round trips. The secondary jet, located nearer the rig is used only if the primary jet fails to function properly 'due to being cut-out by dust-cutting action. Also, the secondary jet iS.used to bleed off the air pressure prior to making connections. The primary jet should be located four pipe diameters from the end of tt~e blooie line for best results. For example, 'if a.7" blooie line is being use[t, the.jet should go 28 inches (7" X 4 ) from the end of the blooie l i~e. The theory behind the location of this jet is not relevant to this paper. It is known, however, tj~at when properly installed, it is far superior to any other jetting method. Actual field measurements have shown that the primary jet will pull 6 pounds of vacuum Oil the blooie' line. The .secondary jet will pull only 2 pounds of vacuum. These measurements were made usi~g the capacity of one 'air compressor (about 1200 CFM) through a 2 inch line and a vacuum gauge installed between the secondary jet and the rig. Air was passed through each , jet at different times, anti the aI/Iou~t of vacuu~n created by cacti jet was noted. Although it is not clearly defined, it is believed 'Lt~at the primary jet will safely keep 3 to 5 MI,1CFD gas production from the rig Floor wllile round trips are being made. Ttli-s is.assu~ning that the rotaLi~g rul~l~er I~as been pulled. Greater volumes of gas may necessitate stripping in and ont o'F 1.11e hole by · leaving the rotating rubber 'in place. The "de-duster" is used to suppress drill cutting dust while drilling. In remote areas the de-duster is used only when the wind carries tl/e dust in tile direction of the rig or other equipment. In populated areas or areas wt~ere dust is not desired, continuous operation is necessary. Water used to suppress the dust can be picked up by a pump 'from the reserve or burn pit and circulated for re-use. The de-duster is easily constructed and installed on the blooie line. The cie- '' duster design shown in Figure 8 can suppress dust at a penetration rate of over 100 feet per hour. , · A "sample catcher" of the type shown in Figure 9 is installed on the blooie line'to catch drill cutting sanlples. The sample catct~er also serves a more important function for drilling people. It allows observation of the dust . . ~ .... , should the dust when the de-duster is being ~sed This is necessary beca~ "disappear, damp or wet down,hole condition exists and 'trouble is t)e~ding or has already occurred. This trouble comes in the form of downhole fires a~ct/or a stuck drill string. The detection and control of these problems are discussed II , · under "Downhole Problems" anti Downhole Fires and Explosions" ,' -. · · A gas sniffer unit, similar to those used, in mud drilling, c~n be t~ooI:ed into the blooie line to detect very small gas entries or background gas (see Figure 6). For convenience' and ease of handling, a h~)ok-up similar to that shown il/ Figure 10 can .be used if. it becomes .necessary to go to mud. A small flat[' ~.'~ :l,:iiot light" should be maintained at tile end of the blooie line. l'his will ignite any gas which'is encountered. One of the most important aspects in air drilling is constant monitoring of drilling pressure. A' minimum of two chart type pressure recorders is required to properly monitor air pressure. One pressure recorder should be on the rig floor, and a second recorder immediately downstream of the air compressors. The rig floor chart type pressure recorder should be a 0 to 500 psig, 12 or 24,hour pressure recorder. The pressure .recorder at the air compressors is a part of an orifice meter run N~here constant pressure and differential are measured. This will allow easy calculation of air volume output at any point in time'which is very important should the air pressure drop or increase. For example, if an increase in air pressure is not accolnpanied by a correspondil~g increase in air volume output, pending trouble is indicated. This trouble could be in tl~e fornl of a wet or damp t/ole condi'L'io~ arbons have been encou~'te~'ed or the t~ole is not beil~g l~'ot)el'ly cle,~e(I. A high-pressure alarm sl~ould be installed on ttle rig floor, This alarm should be set to indicate any increase in drillinq' pressure. (5 [o l0 t~si.g). The action whicl~ sl~ould be taken S]loulcI a pressure i~crease o~' decl'eas'e l~c: eh- countered will be discussed later in this paper. A spring-loaded, dart type float placed immediately above tile bit prevents tile back flow of gas and/or air while making connections or round trips. A bit o sub or bottom Hole drill collar is bored out to hold tile bottom hole float. A flappe'r type float placed in the top-of tt~e drill string inlproves air drilling efficiency. Tt~e flapper or "str. ing float" is placed in a sub bored for this float. lhe string float shortens connecl~ion time by trapping ai~' volt~n~e a~cl t)~'ess~re, between it and the bottonl hole float. Therefore, less tinge is required to get this compressible medium back to drilling conditions. The string float, by trapping air below it, keeps air moving 'around the bit while connections are being made. It is absolutely necessary to have air circulating around the bit before drilling is started. This prevents dry drilling and prolongs bit life. .. Because air, unlike inud, is compressible, a period of time is require¢l to establish air circulation around the bit after a con~/ection is made. Cir- culation aroLlnd the bit is established if there is returns comi~g from the blooie line or the air pressure has reached the normal drilli~g ~)ress~re. Drilling should not begin after a connection until one of these two conditions is met. Short trips can be made to remove tl~e stri~/g 'Float for surveys or to keep tl~e string float as hig}~ in tile string as l)ossible. Also, mo~e than one string float ca~l be run if a short trip is float should be of sufficient ID to allow free point and back-ofF tools to be run through it, should fishing operations be necessary. The string, flapper type float can be held open to bleed off pressure by using 'a bar on a wire' line. Also, a small hole can be bored in the flapper which will allow pressure to slowly bleed off. The string float will present no problem should fishing operations be necessary. As mentioned above, tl~e advantages of the string float far outweigh .the disadvantages. The reserve pit design for an air drilling operation shoUld'provide for a burn pit behind the'standard mud drilling reserve pit (see Figure ll). The "blooie line" should extend past the reserve pit and exhaust'into the burn pit. This will prevent any hydrocarbon liquids from burning and/or flowing into the reserve pit and prevent a reserve pit fire near the rig. Air Requirements · The single most important factor to consider in setting LIp a~l air drilling operation is the volume of'air necessary to do the work. No upper limit has been established for air'drilling requirements; i.e., there 'is i~o suctl~ thing as too much air aVailable. On the other hand, tl~e reason air drilling fails is very often insufficient air volume to clean the hole efficiently under a varied range of drilling conditions. The theory bet/ind the use of air as a circulaci~/g med'iuln ~'alaLi~g Lo such things as lifting powet' and al~nular velocity will I~ot he ~ti',~ctlr;se(l. Wl~i~t is important is the air volume necessary to get tt~e job clone ef'ficient:ly a~cl with the least aIlloL~llt of trowble. An air drilling operation is in trouble iF t~tere is insufficient volume available to handle wet hole, sloughi'ng shales, and mist o.r foam drilling conditions. After air drilling over 3,000,000 feet of. hole with an over-all average pene- tration rate o~ 1,000 feet per day per rig in hard rock, it is knoi, Jn that an air volume of~2,000 to 2,400 cubic feet per minute is adequate to keep the hole clean and drill efficient~ly over a wide range of drilling conditions. This volume of air (2,000 to 2,400 CFM) is based on 7-7/8" hole using 4:2" drill pipe. Larger hole sizes will require more volume, whi.le small hole sizes will require less air volume. A good rule of thumb tO indicate whettier enough air is being used is to stop drilling, and nleasure the time required for the dust to stop or 'clean-up at the end of the blooie line. The time .required to clean the hole.should~not greatly exceed one minute per 1,000 feet of depth. Table 12 indicates a good starting point for determining air requirements. It, should be kept in mind that experience has shown that most of these air volume requirements are lower than what is actually needed to drill an ef'Fi- cient trouble-free hole. As mentioned earlier, most oil field compressors used for drilling will have a maximum pressure output of from 300 to 320 psig. Additional pressure will have to l)e a(:l~iev('.~t by ~;i~g a boosLer, l'l~e bo(~'.;l.el' drilling operations and to blov~ tile drill str'i~g 'loase sl/~uld a sluugl~'i~y sllalo p'r°blcm be fi~'~cou~/t,~red, In,some cases, prevon~ a stuck dr~ 11 string. When formation water production cannot be dried up or hydrocarbons are en- countered, foam or "mist" drilling is necessary. Mist drilling will require about 30% to 40% more air than dusting. Standpipe pressures will be greater. Mist drilling pressures.will range from 200 to 400 psig as compared to 100 to · 300 for dust d~illing. The additional air volume and pressure are required ., because of the weight of the water being lifted. Foaming agents, "soap", and injected v~ater.requirements for mist drilling are discussed under "Downhole Problems". A mist drilling operation can easily become a slug drilling process if drillil!g pressure is not continuously ~,aonitored and soap and ~,~ater injection volumes are not balanced to meet the.existing drilling conditions. Figure 12 illu- strates the pressure behavi, or of mist and slug drilling: Pressure surges .in the hole, caused by heading, are detrinlental to ho'lc condi- tions. For this reason, slug drilling, which is nothing more than moving alternate columns of water and. air up the hole, should be avoided as a con- tinuous operation. Too little air volume is the primary cause o-F slug drilling. In order to conduct a proper mist drilling operation, enough air volume should be available to keep the hole clean and continuously unloaded. Drill cuttings not removed fall back and bridge ~l~(.~n con,~ectio~s are made. When this condition, exists, several things can be doI~e' (1) add n/ore air volunle, (2) sv~ae.l~ t. tle hole with a soap sltlg An increase 'in soap co~centratio~ N,~ill create a stiF'Fel' foam whict~ can b(.~tter cle~n the I~ole and rcinove tt~a heavier drill curt'ling a,~d (3) ~llways l~low tile · hole Umil tile returr),'~mist and air are clean prior to making co~nectio~s. Ihese simp'~, l)rocedtll'es can el.i'minate a stuck drill string.. 17 When the influx of formation water becomes too great to handle by mist drillirlg or lo~t circulation is a problem, aerated fluid drilli~g is used l:o red,Ice the density of the return Fluid column and hydrostatic pressure on ttle Formation by injecting air and fluid into the standpipe simultaneously. · Air volumes used for aeration'are smaller than those used for dusting or misting and are thought of in cubic feet of air per barrel of mud. Figure 133 provides a way to estimate the air volume requirements 'For aeration. The required air volume for proper aeration of a fluid column can be con- trolled with jet subs and by regulating air volume. The ideal aerated fluid conlbines air and fluid into a stable, homogeneous foam that does not break down and separate until it reaches the pits on the surface. The air must break out at the surface prior to reaching the mud pu~nps. Unloading and Drying the Hole The method, proven in actual field operations, to unload the hole of fluid, dry the hole and start air dust drilling.is given below' · Run the drill string, complete with desired drilling hole assembly and bit', to bottom. 2~ Start mud pump and run as slow as possible. Punlp fluid at a rate of 1~ to 2 barrels per minute. This may necessitate crippling the pump to get this rate. This is done to reduce fluid friction pressures to a minimunl and pulnp at a n~ininlun] standpipe pressure for circulation. Standa~'(t fltlid llyd~'aulic calculations will indicate what the standp!pe pressure should be at 1'~-~ to 2 BPM. Bring one compressor and booster on line. This will aerate the f, luid being pumped down the hole. About 100 [o 150 SCFM per barrel of fluid should be sufficient for aeration. If too much air volume is being used, the standpipe pressure will exceed the pressure rating of tile compressor and/or booster. Therefore, slow the compressor down until air is being injected and mixed with the fluid go'ing down hole. e Also, the mist pump and soap injection punlp should be injecting water and soap at a rate of about 12 bbl./hr, and 3 gal./hr., · respectively. The soap will tie the fluid and air together and provide better aeration properties. As the annular fluid column is lightened, the standpipe pressure will drop and additional compressors or air volume can be added to further lighten tile fluid column and unload the tlole. The aeration procedure is far superior when compared to the slug method of unloading the hole. The slug method is acconlt)l'islled by t)U~nl~i~lg al tel'na/:e sl~gs oF w,'~[(~' ,~(.I a i~' (Iown the hole until air can be used continuously. Air is first injected up to an arbitrary maximum pressure, then wator is injected to lower tl~e pressure back to some al'bitrary m'[nin~uin pressure. This procedure is repeated until air can be injected co~ti~uot~sly, l't~e aeration l)rOce~lure rcq~i~'(~s l~)ss tin~), does e 6~ 7, not cause undue surging of the hole due to heading, does not cut .out pit walls because surges are eliminated and can be done generally.at lower operating pressures. When the hole'is unloaded, the mist pump and soap injection pump should remain in operation. This provides a mist BW/hr. per inch of hole diameter and -~i to 4 gal. soap/hr.) which can clean the ho'le of sloughing formations. At this point drilling, usi.ng air mist, can co~l~mence. Drill 20 to 100 feet to allow any sloughing hole to be Cleaiie(t After tile hole has stabilized (no sloughing), stop drilling and blow the hole with air mist to clean the hole of drill cuttings. About 15 to 20 minutes 'is su'fficient or until the air mist is clean. Clean air mist is usually a fine. spray and white in color. ge When the hole is clean, stop air misting, break off tile kelly and pour 10 to 20 gallons of soap followed by 2 to 4 barrels of water directly down the drill pipe. Do not mix soap and~,~ater in mist pumt)'and inject it that way. Pourin.q the soap and water directly down the drill pipe has proven to greater dryi~g effect. 9~ Put the ke. lly back on and set the bit on bottoln. Since hole is now full of air, the soap and water will run to A proper soap sweep cannot be achieved unless it is mixed 1'0. '11. 12. with air and pumped up the 'annulus. This cannot be done if the drill bit is above the soap and water. With the bit directly on bottom, start, ail' down the hole. Pump.,straight'air at normal drilling volumes until the soap sweep, comes to the surface. The soap will appear at the end of the blooie line and look like shavin~ crea~. Continue to blow the hole with air for about 1/2 to I hour. Start drilling and the.hole should dust after 5 to l0 feet have been drilled. Sometimes as much as 60. to 90 feet are required for dust to appear at the surface. 20 If the hole' does not dust .after this procedure' has been followed, pump another so-ap slug around (starting at step 8). If a dusting condition cannot be achieved, mist drilling may be necessary. -. Depending on the depth, tt~is procedure, from start to dusting, requires about 2 to 6 hours. HOles have been unloaded using the aeration mett~od, from depths of over 11,000 feet. Also, a well can be dusted, mist 'drilled, dried up and returned to ~1~,.,I. ~lt'i'l'lillfl. '1t~, k~,y I.o ~ll'yil~!l ;~ I1~'1~'. i" I~,~v~' il. ~"1~',~. In some cases, drying agents I~ave I)(?.e~ tr'ie(l wil:t~ little success. To date, the best drying age,iL ava'ilal~le is , hole below the drill bit. Fol'nlation is al~ excelle~t d~'ying materi a 1. [)ovillhr)l c: [)rr)t)'l /',s mentioned earlier, out-of-gauge bits are a ser'io~is i)r(¢l)l(:~n, l/iLt; ~.Ji~i(:l~ offer the nlo~t gauge protection are used to achieve longest l~'iL 'l'i mil'~'i~iz[, reaming long sections of hole. .Over-~.,i::,,~ today's market~ can e'li~:~i~nt, e re~ni~,'l ~,~,~ ~ ...... s. For example, an 8" mining-type air bi't can ~:.[~ ~"un fi~'st- ']~,,. ,'," l~it can be pulled 1/~)" out of gauge and still be followed by 7-7/8" without any risk of a pinched bit condition due to reaming. Ball and roller, non-sealed type bits, not specifically designed to be used for air drilling, will pack dust (drill cuttings) in the bearings and lock the cones. For this reason, this type bit is not desirable for air dust drilling. The non-sealed bit, ho,,,,'c:ver, can be used ~hen air misting. Other bit types · such as journal or sealed bearil~g bits have been used with satisfactory results in all air drilling operations. One of the most common mi stakes is starting to drill as soon as the bit hits bottom. It is vital to keep air flow so that initial cutting build-up is prevented and bearings are kept cool and clean. Hole deviation can be a serious problem in any drilling Ol~el'ation. In this ·' regard, deviaLion can be colltl'olle¢l, in nlost cases, in a'ir-clrill(~(l t~ole.q through the use and proper application ciples are the "pendulum effect" anct the "packed or sLiff l~ole assembly." The tools necessary to effectively carry out either of these two principles are available on today's market. Some of these tools are' (1) sqLiare drill collar, (2) reamers--string and near bit, (3) stabilizers w'itl~ tungsten carbide insert replaceable wiper pads, (4) air percussio~l tlalnnlers, and (5) large diameter, round drill collars. -11~(., l;,J[,!'.~..~i (,? hi:iff hole drilling assembly has been found most effecLive in air drilling, 'The stiff assom!)l~/ r,t~,:;,',Jl~ '.;: used to eliminate or minimize "doglegs." If drilling off the lease is not a problem, the hole should be allowed to deviate. This procedure has provided the lowest cost holes pos- sible ~.~hen air drilling wells with. total depth of 8,000 to 10,000 feet. On the other hand, deviation should be controlled in the upper part of the hole when drilling deeper air t~oles. "Doglegs" in the Upl)er hole create excessive drag and excessive ¥~ear on drill pipe and tool joints. This is especially true as the well is drilled deeper. The bottom hole square drill collar, with its inherent higt]er rigidity, pro- vides three advantages' (1) deviation control (square collars add 60% nlore strength than round collars and help avoid doglegging), (2) a reaming effect behind the bit, and (3) indication of bit OD wear. Square collars are 1/16" smaller on diagonal than the bit gauge so that any'unusual torque build-up will alert a driller to possible wear on bit gauge. Sql~are collars will inhol'(~.ntly wear at tll~? l~ott'.oi~/ a~.t top of order to minimize this ~,ear, tungste~ carbide 'il~se~'Ls ~l~.l/[.~' pads have bee~ l)lace(t i~ ttlese areas of excessive wc~a¥', 'l'}~(~n(~ in,.;e~'l:s a~]/or pads, 12" to 18" in length, will oxtend the usa[~le life of tl~e squ;~'~ collar. l'he sta-bilizer with tu~lcjsten carbide insel-t l'el)laceable lvit.~c)~' I)acts is essen- tially a shoi-L squ~l~'e collar-, l'l~e a(tv~-tntafle to tills tool 'is t. llat tile wiper pads can be replaced in the field. 23 An excellent tool, proven in actual operations, to control severe deviation and maintain a straighl; hole, is the air percussion hal~,ner. 'l't~'is tool is used 'to maintain a s'traight hole and achieve a reasonable penetration rate wt~ile running ligllt weigh~; (1000 to 5000 lbs.) on tt~e bit. '1'1~ air tla,,ner 'is in conjunction with the "pendulum effect." To accomplish .Lhis, a stabilizer usually is run 60 feet above the bit. The p.lacement of tile reamer will depend on the size of the drill collar being used. The reason for this is that a greater "pendulum effect" or lateral force on tile bit can be achieved due to the stiffness of the various-size drill collars. When an air hammer is being used, there are several techniques which si~ould be used to insure a successful run. To prevent plugging the air t]ammer, remove all rust and flakes from inside non-internally coated drill pipe by rattling the drill pipe and dope the pin end and not tile box when running drill collars and drill pipe in the. hole. To prevent the air hammer from coming unscrewed while going in the hole, make'eacl~ connection up drill collar tigt]t. Also, the air hammer should be tested on the rig floor, using tt~e air volume nor- mally used for drilling. Note the pressure at whict~ the air halnmer operates at the normal drilling air volume. This will allow any malfunction in the operation of the air hammer to 'be detected wt~ile drilling. Tt~e ot-)eration o'F the air hammer should be checked periodica'lly. Stop al'tilling, leave weigi~t on the bit and.air on the hole, place a steel object against the kelly and near the ear and listen;.a faint buzzing sound will be heard if tile air hammer is working properly. Air bare, ncr manufacturers recom~nen(l I)ouri~g a small amount of oil down tl~e (trill pipe periodically to lubricate t,i~e m(,ving i'~rts of tt~: ~ ~ 24 air hammer, l,lith proper care and handling, an air hamlner can r~ln 150 to 300 hours. Bottom hole drilling assemblies which are. being used to control deviation in air drilling afc illustrated in Figure 14. Drill pipe and drill collar wear in air-drilled holes does not appear excessive and may even be less than wear in mud-drilled holes. For example, one string of pipe'has been in continuous air drilling service for l!i years with over 380,000 feet of cumulative hole, and annular air velocities'have been 9000 FPM. This string of 4~-i'', 16.60 pounds, Grade E, X-hole drill pipe reflects a minimum wear of 0.067" (20%) loss of tube wall thickness, 0.53" (9%) loss of 'tool joint OD, and 0.31" (57%) loss of shoulder width. A periodic inspection of drill pipe is good drilling practice because drill l)ipe failure in an air hole can result in a junked hole. The inspection of this string of drill pipe revealed that 297 joints (91%) of 327 joints were still premium pipe. Ten joints were rejected due to thin average wall thickness. This particular string of drill pipe is in.ter~ially coated and hard-banded. A dri.ll pipe string has been known to have been in continuous air drilling operation for about 1,000,000 feet before being replaced. This is probably a maximtlm example of drill pipe use in air drilling. However, this does point out that air drilling is not excessively d~maging to drill pipe if proper precautions-and handling techniques are employed. Air drilling evidence has shown that drill pipe erosion can occur between the hard band and the tool joint metal wt~en tile box end is llard-banded. 'This erosion is due to drill ct~tting bombar<t~nent similar to sand blastii~g. This type erosion can affect' the life of a joint of dr'ill pipe. Design work for drill pipe to be used for air drilling has not kept pace w'itt) other advances in the technology. Maybe, if hard-banded drill pipe is cte- sirable, the ha'rd band Should be put on the pin end raL))er ti)an tl)e box end thereby mininlizing tool joint wear due to erosio~l at tile hard ba)l(l, tool joint interface. This may require 1. onger tool joints. Excessive'wear on a square collar can cause deviation problems due to changes in bending and stabilization characteristics. Therefore, a square collar should not be allowed to wear excessively before changing it out. The fact that a square drill collar was used ahead of the above-mentioned drill piP'e helps explain the exceptional perfornlance of this string of pipe. Square drill collars minimize "doglegs" and "doglegs" wear drill pipe. This is particularly true when "doglegs" are in a sharp, abrasive sand. Air drilling in any form ~equires 24-hour supervision. Constant supervision must be maintained because trouble can occur quickly and compound so fast that air drilling econoniics are lost and expensive fishing operations i"esult. 'Avoiding problems and expensive fishing operations can be accomplished througi~ proper supervision and application of prov-en air drill-lng techniqLles. For example, to avoid running bit cones off, bit torque should be monitored continuously. Checking hole torque off bottom and bit torque on bottom will provide an accurate measure of a bit's ability to turn properly. 26 Insufficient, air volume to clean the hole can and does result in stuck drill strings.. This problem is most likely to occur while mist drilling or due to sloUghing, of wet and'/or dry sands and shales. 'The lack of arl,~ buoyancy effect in an air hole creates dc~ad loads' of froln 10% the drill string and the bole'further compounds these dead loads. Abnorn~al drag is dangerous and a, possible sign of pending trouble such as a stuck or parted drill string. This type of drag occurs when the hole is not being cleaned and cutting load is building up or when a sloughing' hole condition is present and large ,chunks of formation are wedged between the hole and drill string or excessive doglegging exists. When an abnormal drag condition exists, it is possible that the drill string will become stuck. In order to prevent the drill string from becoming stuck, due to pulling into and packing dry drill cuttings, never pull on the string without air circulation. The air will keep the cuttings ~noving and allow them to work past the drill string'. ,, Should. the drill string become stuck, excessive pulling ustlally will not help free the .pipe. A good practice, proven in several field operations, is to ~blow the pipe free with nitrogen under high pressure. This operation is easily accomplished witt~ liquid nitrogen available fei'L oil Field use. Also, this procedure will only work if the drill string has not been pulled ex- cessively and the cuttings packed tight. tlole, dr. ag and torque can be nlinimized by using g~'aphite for lubrication. Dry chenlical injectors are available to i~ject graptlite directly into tt~e air stream. A hole can occur in the drill string while drilling. This very dangerous condition is noted by a drop in standpipe pressure. When this occurs, stop drilling and se~ weight on the bit. Leaving bottom with a partially-parted drill string m~y result in expensive fishing operations or a junked hole. There is little chance to recover the dropped pipe due to the cork-screwing and breaking of the drill string. Also, any attempt to try to part the drill string with the bit on bottom can produce the same results as dropping the string. . A procedure, proven in field operations, is to set the bit on bottom, locate the hole by reverse circulating and running a horizontal spinner survey. By knowing the exact depth of the hole, the 'drill string can be set in a neutral weight position and backed-off below the hole. After back-off is accomplished, the string can be fished with conventional methods. Water entry into the hole is a major deterrent to an air drilling operation. The degree of wetness ranges from damp to water flows. Damp or partially wet conditions can be dried-up by using soap slugs mentioned earlier. As long as a continuous drilling operation exists, the hole should remain relatively dry. tlowever, after each trip, the hole may have to l)e redried. Large water flows may require aeration for air (Irilli~!l ~f~e~'a[io~s to co~- tinue. Should a water flow be drilled into, indicated by 'i~lcrease in stand- pipe pressure and loss of drill string weig}lt, tl~e d~'ill sl;ri~g sl~onld l~e pulled 'immediately under certain co~ditions. The reaso~ Fc~r tl~is 'is ~o prevent sticking of the drill stri~g, caused by slougt~ing, water sensitive, shales when the for~nat:'ion wal:(:r is relat:ively Fresll. Many materials such as cement, plastics, and chemicals are capable of s}~uLting off water. The difficulty is in the proper evaluation of the water producir~g zone and the ul'timate ability to place the shut-off material where the .desired results are achieved. Readjustment' of the casing programs to fit air require- merits is the answer to water shut-off in many ,areas. Wt~en a hole makes water arid it cannot be dried, "mist" or Foam drill'iilg proceed by injecting a foaming agent into the air strea~n. A good Foaming agent, "soap", which generates a stable foam with enougl~ film s'Lrer~gttl to keep the hole c~ean and relatively free of produced water st~ould be used. A good rule of thumb is to inject 1-~ barrels of water per hour per inch of t~ole diameter plus 1/2 gallon to 6 gallons of soap 'per t]our. Soap should be injected with a separate injection pump. The volume oF soal~ st/ould .be kal){: at a minimum value sufficient to clean the hole. An increase in the concentration of soap gives the foam more stability and increases its carrying capacity. Mist injection water should inhibit shales and the pl-I should be on the basic side. In some instances, corrosion inhibitor should be used. Depending upon conditions, particularly.tile volume of water flowing into tt~e well, tt~e con- · . centration of soap may need to be changed. I'f insufFicie~t soap is used, there will be considerable'tleadil~g. If too I~lLlcl~ soap 'is w:,(;d, LI~(; well will head with slugs of heavy Foam and ilo liq~'id d'is(:l~arge. '1t1~ l(~we,.~t col~ce~- tration of soap that gives a steady flow from tile blooie line and a steady standpipe pressure is tile anlount desired. Downhole Fires and Explosions - "Burn Offs" It is a'well-known fact that three conditions must be met in order to start a fire. There must be fuel, oxygen., and ignition or combustion. Wtren gas is encoUntered during air drilling, the first two conditions are Inet--Fuel in the 'form of natural' gas and oxygen in the form of compressed air. ,. The main concern, when gas is encountered while drilling with air, is to prevent ignition. In order to do this, the causes of ignition while drilling with air must be known. Three things~will cause ignition during an air drilling operation. These are' (1) a "mud ring" (seal beLween bare t~ole and drill string), (2) downhole sparks, and (3) a small hole in the drill string. -. Mud rings are the primary cause of ignition which causes downhole Fires or "burn-offs." Ignition will occur, with proper fuel to air ratio, when a seal around the drilling assembly is formed. This seal is in the form of a "mud ring" created by drill cuttings and moisture. When the mud ring is -Formed, air circulation is stopped, and gas continues to accumulate in a pressure · · chamber, similar to the ignition chamber in a diesel engine. Ignition then occurs in this chamber when the gas-to-air ratio is in the 5,,°°' to 15°~,~ range, · Figure 15.4 Therefore, by sealing off the air circulation and enriching the gas mixture, burn-off can occur witt~ very small gas entries. Based o~ actua'l exl~er iel~ce. Fralll sevel'al (lowl'~tlo'lu F it'~;~;, ~l,~l.i~ 'J~,li~:,~l.~,'.; 1.1~,~1, most burn-offs occur in the drill collar string. Also, most bur~-oFfs occur at the top of 'the gas entry zone. In almost every case, al; tl~e tinge of a burn-off, the drill string has been stuck, indicating i'.l~e l~resence ring. l'he two other sources of ignition for which there is little 'or no control while dust drilling are downhole sparks and small holes in the drill stri~lg. When drilling hard quartzite sands, sparks are caused whe~ tungsten carbide] bit inserts, drill collars, and drill pip.e tool 'joints strike tile hard face of the 'bore hole." These sparks are a source of ignition in the proper fuel to air mixture. .The other source of ignition is a small pinpoint hole which can develop in a drill string. It has been demonstrated that when air (200 to 400 psig) is flowed through a pinpoint size hole that the friction drop across this hole creates enough heat to cause a hot spot. This hot spot can aid ignition of the right air-gas mixture. Downhole fires .and explosions cause extensive damage to the downhole equip- ment. Drill collars and pipe are melted and slag has been blown up-tlole several hundred feet. Even though downhole equipment is damaged or destroyed, there is no damage to surface equipment. Most of the time all that is known at the surface is .that the drill string is stuck, and a sur'Face recording temperature survey may have to be run through drill string to determine if a fire occurred. Because of damages incu'rred to downhole equipment a'Fter a burn-off, 'fishing operations are difficult and sidetrack operations are necessary in order to drill decider. Tl~is type operaLio~ is exl~ens'ive a'~d t:in~ c~sum'i~l. There- fore, the prevention oF a downl~ole fire or ext~'losior~ i~, There are two positive methods to prevent downhole fires wt~ile drillirlg. The first is to drill with Fluid. Thi.s method is Imlct~ too exl~ensive aI~d slow for Illargina] gas plays. The second method is to drill I)ote~tial pay zones with gas, als() exl)er~sive at toclay's gas prices. From a practical standpoint, a well could be air drill(~d to top oF potential gas pay zones, then gas drilled ttlrough tile pay. Itowever, gas 'is ~ot always available and drilling every potential gas pay with gas carl be expensive and will be more so as the price of'natural gas goes' up. At present, mist drilling is the most conimon method used in preventing a burn-off when gas is encountered. There may be no absolute.method to prevent a downhole fire while dl'illing with air; however, certain measures can be taken to lessen tile chance oF a burn- off. Constant supervision is an absolute necessity in any air drilling ope- ration. This is especially true when air drilling a potential gas pay. Pressure recorders with high pressure alarms able to sense 5 to lO psig increases in standpipe pressure are necessary. The pressure recorder denotes the formation of a mud ring or back pressure from gas entl'y througl~ pressure increase on the standpipe. When a gas show or an increase in standpipe pressure is noted, several steps mUst be taken to prevent a burn-off. These steps are' · · I. Immediately stop drilling. ' II. Shut air off and monitor gas flare. A. If gas flare sustains, determine wf~etl~er or not gas is wet by llotir~g' · Wetness oF cuttings at saint)lc catcl~,.~'. · Black smoke and/or yellow color of t)urnil~g gas, indicating distillate in gas. III. 3~ Sparks at end of "blooie line", indicating drill cuttings are damp with distillate. Be If gas flare will not sustain or burn with air off .,proceed to Step III. Put air back on the hole ~nd determine if gas is wet. A. Do not drill at this time, as new cuttings may form mud ri ng. Be With air on, pass tool joints to prevent the'formation of a "mud ring". IV. V~ If gas is wet (l.~ater or distillate) as indicated in II-A, II- B, and/or III above, mist 'drill or drill with gas. If gas is dry, or no sparks, no black smoke, or no wet samples at surface' A. Dri.ll 5 to l0 feet. B.' Pass tool joints to avoid pressure increase by mud rings. C~ Continue to drill at 5 to 10 feet intervals u~ltil it is detei'lnin(~(l tt~l, a wet Uas (:o~cl'it:'io~ <l~f~:; ~I. ~_,.xi~;t,. During all of tl~e above steps, wt~ile ttle air is on tl~e I~o1~.~, in(~lli[or LII(! standpipe pressure constantly. As long as the standpipe pressure is above normal drilling pl'essul'e, the prospects of a burn-off al'e good wt~(.~n gas is · encountered. Remember--it takes only a very small amount of.' gas to ignite a burn-off when a mud ring is present. Partial mud ring or closure .in the annula.r space restricts air flow causing standpipe press'ure to increase. Complete closure can occur quickly and will not be noted a't the surface immediately due to the compressibility of air. For this reason, quick action is necessary to prevent a burn-off wt/ich starts with "stop drilling." Assuming that drilling is not stopped when a gas show or pressure .increase is noted, the following events will occur' · · A small increase in standpipe pressure occurs. Drill cuttings become damp due to distillate or water, l't~ese cuttings begin to pack together and form a mud ring around the · drill string. e As the mud ring closes, pressure will further increase to the operating capacity of the compressor. 4. The drill string is stuck, indicating a mud ring is formed. e Ignition of a downhole fire then occurs. This ignition is similar to a diesel engine igl~'ition. Based on field experience of actual downhole fires, it requires no more than 40 feel of drill CLILti~gs to generate el/oLI[ll/ cIusL [o c~-eaLe a mud ring and ignite a burn-off. le REFEREHCES C'unningham, R. A. and Eenink, J. G., "Laboratory SLudy of Effect of Overburden, Formation and Mud Column Pressure on Drilling Rate," Paper 1094-G, Fall Meeting, AIME, Houston, Texas, 1958. 1 Angel, R. R., "Volume Requirements for Air or Gas Drilling", Trans. AIME (1957). e Poettmann, F. H., and Begman, W. E., "Density of Drilling Muds Reduced by Air Injection", World Oil, August 1, 1955. Reprinted from Bureau of Mi~es Report of InvestigaLio~s 3798. 12 8 , , INDIANA LIMESTONE i 150-450 MD. PERMEABILITY 11/4 'IN TWO CONE ROCK BIT ~ 6000 PSI OVERBURDEN - 150RPM 1000 LB. IT WT. I , , 10 6 4 2 Z 1000 2000 3000 4000 5000 DIFFERENTIAL 'PRESSURE - PS! /--~.4 FF.. BEST GAGE CONE BLANK SHOULD G C HERE SECOND BEST GAGE CONE 0 PTIONAL-~7 Z A I I{ F R 0 M COM I't{ESSOI{S MOVING SEAL HERE GAS OR AIR DOWN THRU KELLY ROTATES WITH KELLY CUTTINGS A DISTANCE FROM RIG BOOSTER, COMPRESSORS MIST UNIT SOAP PUMP STANDPIPE '"'x F L O W METER TO FLANGE FOR GOING TO FLUID SAMpLE'CATCHER.] FILOT LIGHT ' RESERVE --/ [PRIMARY JET PIT WALL/ o--. l-qI o 2" AIR LINE FI{OM ST AN D P I P E MANIFOLD 1" WATE~ FROM WATER P U M P 150' TO 200' -GAS SNIFFER J'ET HEAD STEEL P IT SEC O N D A'R Y [ROTATING L2" AIR LINE FROM STANDPIPE MANIFOLD 4" COLLAR 2" UNION7 /AIR 2" SWEDGE __. ~~ '3/4"TO I"TUBING 1/4" PLATE ....~ COVERED WITH CUT IN HALF -Nd HOSE 4D FROM 2" uNIoN] PRIMARY JET SECONDARY JET WATER FROM WATER PUMP7 AIR .FLOW r--.~ ~' COLLAR SQUEEZED FOR E N D V I E \V METAL SHIELD ANGLE IRON INSIDE BLOOIE LINE ~ ~' AIR L,>,, NIPPLE LE DISCttAtlGE FLOW r~DGE OF SUBSTRUCTURE ~AIR BLOOIE LINE BRACE-~ STEEL MUD [)IT ROTATING H 7-0 RIG STEEL PITS ~N SLUGS cuRVE REABLE %0 0 0 0 0 0 0 0 0 fid fO 180 ) REDUCING FLUI .~r) ~HTS BY AERATION ~. >) AVERAGE FLUID COLUMN flEMPERATURE 125°' 175° F CU. Fr. OF AIR AT 14.7 ?SIA & 60° F PER BBL. OF MUD I1 BBL.= 42 GALS.I 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Wa :ACTUAL FLUID WEIGHT BEFORE AERATION LB S. / GAL. Wd :DESIRED FLUID WEIGHT AFTER AERATION LBS./GAL. · LBS./GAL. Wa -Wd LBS./GAL. 1000 2000 3300 4 000 5000 t 6000 7000 8000 9000 10,000 TO Fi: u 'AIR DP.!LLI[iG qEPTF I~i FEET l) Fin" =~qllin~ depth in feet on bottom scala ~ G~ u: ~o a~prop~ia~ curve o= 2, , , ~ ~ Desired F'ui~' ',.:eight After Aeration (Wd). 3) G~, a~,-oss to the appropriate curve of the d~fference between the Actual Fluid Weigi~t P:f~'-e Aeraticn and the Desired Fluid tleight Afze:- Aeration (W -Wd) 4) Go u- to the Cubi~ Fee~ of Air needed [:e,~ -~.-rel of Xud on top scale EXAY, PLE (Follov: 1) 4200' deep hole Dotted Lines) 2) Up to 6 lb./gal. Desired Fluid Weiqi~t After Aeration. 3) Over to 4.5 lb./gal. (i0.5 lb./eel. Actual Fluid ',,;eight minus 6 lb./qal. DesireJ Fluid Weight). 4)Up to 73 Cubic Feet of Air ,/. INDEX 1 - ROUND DRILL COLLAR 2- SQUARE DRILL COLLAR 3 REAMER 4- STABILIZER WITH REI'LACEAI~I.E WIPER I'AI)S 5 SHORT S('.I UA RE DRILL COLLAR 6- JET SUB 7 Alit I'RECUSSION 11 A ~I M 1,; I( .< 400 360 320 280 240 2O0 160 120 8O 4O 0 _ ,1 ii i i i , i i i ii i iii i , i 0 × INFLAMMABLE AT M OS l't1151{ IC 0 8 1 6 2,1 3 '2 4 () NATUI~AL GAS IN MIXTtJI~.E % BY VOI, I.I~I TABLE 1 AIR REQUIREMENTS ESTIMATED PENETRATIOH RATE - 50 FT. PER HOUR Hole 'Si ze' 17 1/2 Drill Pipe 6 5/8 5 1/2 4 1/2 Dep_th and Vo 1000 · 2000 40-00 6150 6600 7150 6450 6700 7400 6600 6850 7550 6000 8000 10000 12000 7700 8400 8950 9500 8000 8550 9100 9650 0 8100 8700 9250 9~00 12 1/4 ll 6 5/8 2600 -2800 3000 5 1/2 3000 3100 3350 4 1/2 3100 3350 3700 3400 3700 4150 4500 3900 4300 4700 5000 4200 4500 4900 5400 6 5/8 2000 2150 2350 5 1/2 2300 2400 2700 4 1/2 2500 2600 2900 2650 3200 3550 3900 3000. 3300 3700 4000 3200 3400 3800 4100 9 7/8 1/2 1/2 1700 1950 2150' 1900 2000 2300 1950 2100 2400 2400 2600 2850 3100 2600 3000 3300 3600 2700 3200 3500 4000 5 1450 1550 4 1/2 1550 1700 3 1/2 1700 1850 1850 2150 2350 2550 2850 2000 2300 2500 2700' 3000 2200 2600 2700 3000 3300 8 3/4 5 1350 4 1/2 1450 3 1/2 i600 1500 1650 1750 1700 1850 2000 4 1/2 3 1/2 7 .7/8 7 3/8 ,3 1/2. 107() 1150 130[) '6 3/4 3 1/2 850 lO00 1200 2000 ~2[0 2400 2700 2140 2400 2600 2850 2280 2600 2800 3000 1100 12OO 1500 1800 2100 2350 2650 1300 1400 1650 1900 2120 2400 2700 3 1/2 710 790 930 6 1/4 2 7/8 790 850 970 1420 1650 1850 2100 1030 12I~() 1420 1 650 11 50 1420 17{]0 1 4 3/4 2 7/8 430 500 650 790 930 1 070 1