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Home My WebLink About1987 Endicott Oil PoolStandard Alaska Production Company 900 Eos: Benson Bo,le.wd P O. Bo+ 196612 Ar.cno:aae, Alos4a 99519-6617 (907) 564-4029 M.I. Curtis V,e Prss:tle— is -aa -87 Alaska Oil and Gas Conservation Commission 3001 Porcupine Drive Anchorage, AK 99501 Re: Pilot Waterflood, Endicott Field. Dear Commissioner Smith: STANDARD ALASKA PRODUCTION December 4,1987 Standard Alaska Production Company respectfully requests permission to implement a pilot waterflood project in the Endicott Field. The objective of the pilot is to enhance the planning and implementation of the full field waterflood approved in the Field Rules. Injection is planned into three or four wells located downdip in the 2A, 213, and 3A zones at an estimated total rate of 30,000 to 40,000 barrels of water per day. Three wells have been currently identified as pilot injectors and are described in the attached exhibits. Prior to commencement of injection we will inform the state of the final selection of pilot injectors and submit the necessary reports for change of status on all wells. Your timely review and approval of this plan would be appreciated as we would like to begin injection at the end of January 1988 subject to availability of waterflood facilities. If additional information or clarification is required please contact A. W. Ross at 564-4757. / h�- e HLH A unit of the original Standard QI Company Founded in Cleveland. Ohio, in 1870. M. I. Curtis V. P. Development Programs RECEIVED D E 0 17 5�'ni Alaska Oil & Gas Cons. Commission Ancho.age ENDICOTT PILOT WATERFLOOD PLAN SUBMITTED TO ALASKA OIL AND GAS CONSERVATION COMMISSION DECEMBER 1987 PECF1VED avaska Oil & 6., ,,.r,;. �uonmissloa LIST OF EXHIBITS I. Waterflood pilot plan and objectives. II. Monitoring program. III. Zonal maps. a. 2A b. 2B c. 3A d. 3B e. 3C IV. Type log. V. Injection well schematics. a. Sag Delta 10 b. P-24 c. 0-28 VI. Waterflood facility schematic. VII. Water injection tests summary. pizskz 011 & Gas Cons. Commisst a Anohorane EXHIBIT I RECEIVED PILOT WATERFLOOD PLANS AND OBJECTIVES L•' ryco/' Alaska Oil & Gas Cons. Commission Anchorage A pilot waterflood is planned for the Endicott Field with startup about the end of January 1988. Injection will be into zones 2A, 2B, and 3A through a total of 3 - 4 wells. The primary objective of the pilot is to enhance the implementation of the full field waterflood scheduled for early 1989. As discussed in the Endicott Field Rules testimony water injection will occur in wells placed in down dip positions along the periphery of the oil columns in the continuous 2A, 2B and 3A zones. Zone 3C continuity has not yet been confirmed so the waterflood pattern to be utilized will be decided after further delineation and performance analysis. Data from both development drilling and additional reservoir modelling studies confirm peripheral injection as still the best waterflood scheme in zones 2A, 2B and 3A. Development drilling has added a good deal of information with regard to the tar mat that underlies the oil column over all of the reservoir. Exhibits IIIa thru IIIe show the areas of each zone containing gas, oil, water and tar. In some areas of the field the tar mat underlies the light oil column with little or no aquifer between the accumulations. Placement of injection wells in these areas will have to be either in the lower part of the light oil column or below the tar. Injection directly into the tar sand can not be accomplished at required rates. A pilot injection well below the tar mat is being considered to provide data on pressure support that could be obtained through the tar. Without this information dependence on injection below the tar for pressure support would be uncertain. Two wells already drilled, Sag Delta 10 and P-24, have been selected as pilot injection wells. These wells will provide injection down dip into zones 2A, and 2B respectively. Well Q-28 is to be drilled in January 1988 and will be targeted as a 3A injector. A test of water injection below the tar may also be attempted in 0-28 if the well location permits. Well locations are shown on exhibits IIIa, IIIb, and IIIc. Pilot well injection rates are dependent on offset well producing rates. Site specific reservoir simulation models will also be used to determine the best injection rates. Injection rates in the range of 8,000 to 12,000 barrels per day per well are anticipated. The following items can be determined or monitored during the period of pilot operation prior to full field waterflood start and will provide valuable information for the full field implementation. Determine well/subzone injectivities Determine pressure response to water injection -1- EXHIBIT I Evaluate sand continuity and fault communications Establish and test a tracer program Evaluate water injection control of gas cap advancement Identify thief zones Obtain early indications of breakthrough performance Shake down waterflood equipment -2- EXHIBIT II PRODUCTIVITY AND INJECTIVITY MONITORING A program of productivity and injectivity monitoring is necessary to achieve the best possible recovery from a waterflood. Operation of the waterflood pilot will allow for the testing of surveillance methods that can be developed into an efficient program for the full field waterflood. In addition to injection rate, wellhead pressure, producing rate, GOR, water cut, and bottom hole pressure, downhole production logging tools will be utilized to monitor waterflood performance Spinner surveys will be utilized on each water injection well and offset producing well to determine into which vertical intervals fluid is being injected and from which fluid is being produced. Surveys will be run initially to establish baseline data and rerun when well characteristics indicate a significant change. Prior to the initiation of the full field waterflood all of the surveillance information and methods will be reviewed and a monitoring program will be developed and submitted to the Alaska Oil and Gas Conservation Commission for approval. �4V � Fyasks Ol; & Gas cons. GOT"n" :on An-'tc ane NOTE: OIL IRECTLY OVER TAR i LEGEND--_ I 2A HYDROCARBON CORRIDORS * UIL OVER -L_,-SDI WATER WATER OIL GAS OVER OVER OVER OVER TAR TAR TAR WATER OIL OIL GAS F- f 1 I ! I L I I I LI��ENDICOTT PARTICIPATING AREA BOUNDARY L- NOTE: OIL )IRECTLY OVER TAR ZONE 2A HYDROCARBON CORRIDORS 1 a L��ENOICOTT PARTICIPATING AREA L � BOUNDARY LEGEND •- _l - " / 1 L- �k OIL OVER 'Sp WATER WATER OIL OVER OVER OVER TAR TAR TAR WATER m x GAS / OVER OIL OIL GAS Im J NOTE: OIL DIRECTLY OVER TAR TAR LEGEND * OIL OVER WATER WATER OIL OVER OVER OVER TAR TAR WATER GAS OVER OIL OIL GAS ZONE 2B HYDROCARBON CORRIDORS :'J L'�/ENDICOTT PARTICIPATING AREA _- BOUNDARY II J 38 \ I � Jo ss b 2A/ti I_ 1 SA 9 I \ L_ � S(X I II I I I � W 1 / ZONE 26 HYDROCARBON CORRIDORS L_ ENDICOTT PARTICIPATING AREA LK�BOUNDARY * NOTE: OIL DIRECTLY OVER TAR � I TAR LEGEND * OIL OVER WATER WATER OIL OVER OVER OVER TAR TAR WATER MT GAS OVER OIL OIL GAS , 1 I1 I 1 I I I I I I L_ I---- �- I k NOTE: OIL DIRECTLY OVER TAR i LEGEND_ * OIL OVER WATER WATER OIL GAS OVER OVER OVER OVER TAR TAR TAR WATER OIL OIL I m x W ZONE 3A HYDROCARBON CORRIDORS ° LI�/ENDICOTT PARTICIPATING AREA __ BOUNDARY xe:r J e• L- * NOTE: OIL DIRECTLY OVER TAR Wry L_�� LEGEND I * OIL OVER WATER WATER OIL GAS OVER OVER OVER OVER TAR TAR TAR WATER OIL OIL GAS , ZONE 3A HYDROCARBON CORRIDORS ° L' ENDICOTT PARTICIPATING AREA .�BDUNDARY I nn air � r air X it x.40 NOTE: OIL ;IRECTLY OVER TAR r I I L- _LEGEND * OIL OVER ZONE 3B HYDROCARBON CORRIDORS r rNDICOTT �BOUNOARYPARTICIPATING �L__ I WATER WATER OIL GAS OVER OVER OVER OVER TAR TAR TAR WATER OIL OIL GAS r I I I I mug I 1 CL ARBA NOTE: OIL DIRECTLY OVER TAR I L m x x ZONE 313 HYDROCARBON CORRIDORS = a i L4��ENDICOTT PARTICIPATING BOUNDARY AREA CD r l ,_77 T N �` f it 3 a I I � I L-1 1 ZONE L_ !- 4 MPI i NOTE: OIL DIRECTLY OVER TAR I � LEGEND * OIL OVER WATERWATER OIL GAS OVER OVER OVER OVER TAR TAR TAR WATER OIL OIL GAS hM m x x 3C HYDROCARBON CORRIDORS i L/ENDICOTT PARTICIPATING AREA -_ BOUNDARY I Y I I L�� ZONE * NOTE: OIL DIRECTLY OVER TAR LEGEND * OIL OVER WATER WATER OIL OVER OVER OVER TAR TAR TAR WATER GAS OVER OIL OIL GAS m x x a 3C HYDROCARBON CORRIDORS I L�/ENDICOTT PARTICIPATING AREA , BOUNDARY I ` Y EXHIBIT IV TOP KEK 3C m 3A m 2A BSMT TYPE LOG GAMMA RAY BULK DENSITY 200 2.0 3.0 :e ��■�� 3C40 3C30 3C20 :60 . 3B30 3B20 a :. 2829: . 2811 m�� E��E� EXHIBIT Va GO( MPI WELL 5-02 / SAG 10 FHOICOTT COMPLFnOH DIAGRAM WELL f -SISAL DEITA ]lD «e»e«Y (ENDEAVOR ISLANDI YEM nrvo ® iV«RELYND RCOMFr01 p] R ]m R RYCf IXTx. SyELIIC%BI! �}yr- RurT l 0 \YR %u R >W rf rO.ION:]Y E:]N4L'Y OEOI ]lm ri ♦IT, Iz.uRr Lw I.. lw.q \ara6wYza,aa�n IFR�WrFO ]m]m ON Ll xY.o .. I - r.ou(r Nfn.6 rnw rv\wi.un ..rR m.n n rwv rr LGIOE.M Tm }4T r.c.(. .Ytr n IV. DF.M I.VPt v\\Rw(w raw(\ rL16\lp «» rt »av rt leen-n-n roP 2 9 OWC. TOP MPI M. D. _ ♦ar nYR xr]ws wcc «Y n GOC BASE M.D. STRADDLE PT CEMENT rn.. wn\\ SONE T BOT B TVDTOP Oiq }.4 T MIrIL( M:D: •'... •. •. •• ................ ...........u................... 02/SG10 DIL/SFL 2A 12650 12680 30 10110.00 Oiµ }I? T 111 WALE 12146 NO ACTION Ij 2A 12770 12795 1W FMMOLOE 10200.00 10220.00 12800 Ofq v.P ]M][fn .�E 12870 30 Om }T TSE .( Oip }lW1T -»! rVRE DETfIq Ox'FMI110.IX V�rOCM Oi6l.P Oa MM 0xZl lwwiw.mE - wo\.cEro c0«/LRIOM ILWO: \J PTO M.E leen-n-n roP 2 9 OWC. TOP MPI M. D. K. D. GOC BASE M.D. STRADDLE PT CEMENT WELL LOG/DATE SONE TOP BOT B TVDTOP •M.D. LT. •OIL•.TOP•:••• M,D �..... M:D: •'... •. •. •• ................ ...........u................... 02/SG10 DIL/SFL 2A 12650 12680 30 10110.00 •TVDBO: 10132.66 12146 NO ACTION 2A 12770 12795 25 10200.00 10220.00 12800 2A 12940 12870 30 10252.00 10215.00 EXHIBIT Vb MPI WELL 1-37 /P-24 TOP 3B Rt ELEv.. �- W ELE V ,REE .. -ITIS' . SBDJ Ps. C-AQF O ELLNEAD - Clw3-"' - I— PSI SSSV ' ISM, J- A 117. 12.10IR, L -e0, IDS TUBING GAS LIFT MANDRELS (I TOTAL) tt "W TVDSS CALCULATE n 02V wow FROM I] mywm GCTIGYRO e. e)DDTVDSS SURVEY t5E.A%'TVDss a T, AB:TIE BTM GLM IN, CABS TVDSS 2 o ABOVE ss 2 JTS - I In- IDS TUBING e 1I2- OTIS Z SUGINO SLEEVE 1 JT - A Ir4 TOS TUB -NO I Ne- RETR. PACKER WRUe1NO SEAL ASSEMBLY TOP T LINER S "r, LL/FT, L. , TOS TUBING E "- CSG SIIDE OTIS.PORTEO NIPPLE ,I- OD BLAST JOINTS (SET S' (-) ABOVE PERFORATIONS( PERFORATIONS: BYO )eGlTau (f BAASI m SET T MOV FERFOAATK,NSl T' PERM. PACKER WIFUBING ANCNOR (SrF 10' BELOW PERFORATIONS) 1 _ 2 TIr PUP JOINT 2 TIt- •C• NIPPLE _ - 2 2n- PUP JOINT 2 m- Y NIPPLE - 2 TIt PUP JOINT WIRE UNE ENTRY GUIDE w 2Suvw11NI BETWEEN VM1ED NONF%2 FEPFtlYTVISi PEAFGRATIONS: TO PBTD . STANDARD ALASKA PRODUCTION F—yl'f)IrOTT WELL 1-37 1 P-24 PROPOK D- m FT10N DIAGRAM 1F'PFE DATE: 1"*207 DAAwN er:_ _ TYPE COMPLETION TOP 3A TOP 2B' Owe M. D. M. D. TOP BOT fffkRfflfkffRffkfffffffkff ffflf ifffflff fif RfffRlf iffllf ff PERFORATIONS 12282 12314 12360 12408 12446 12490 EXHIBIT Vc Q-28 TYPE LOG Nam ENDICOTT FIELD GC 98 ON 10' N. MARI TD 10605 PROGNOSIS FOR 0-28 TO BE DRILLED 1/88 3775 9915 10125 10275 10450 '-27 8'0-32 ale Not Accurate 10625 Itkilyariaki 1 ONE 3C - t t � U 9 1 im WIIIWI ZONE 2A Based • �IYWW Vertical & TD 10605 PROGNOSIS FOR 0-28 TO BE DRILLED 1/88 3775 9915 10125 10275 10450 '-27 8'0-32 ale Not Accurate 10625 PRODUCED WATER FROM PHASE SEPARATORS CORRUGATED PLATE INTERCEPTORS MARINE BYPASS SEAL GUARD SEAWATER on FISH SCREENS ENDICOTT WATERFLOOD SYSTEM SCHEMATIC UPFLOW DUAL -MEDIA FILTERS (6) STRAINER HEAT EXCHANGER WASTE WATER TANK STRAINER BACKWASH I DOWNFLOW DUAL -MEDIA I l FILTERS (4) DEAERATOR INJECTION WATER INJECTION TESTS SUMMARY Water injection tests have been run on 3 wells in the Endicott field since June 1987. The three wells in order of testing were Sag Delta 10, P-14 and 0-16. Results of the tests have been carefully analyzed and conclusions have been reached regarding injectivity and required water treatment. Additional testing will be conducted at the start of the pilot waterflood when installed treatment facilities are available to verify the conclusions. Injectivity tests were first conducted in the aquifer/tar saturated zone 2A of Sag Delta 10. Injectivities were low due to the high tar saturation but rates were sufficient to conduct a step rate test and establish a fracture gradient of .58 psi/ft. Injected fluid was filtered seawater pumped from truck mounted pumps. No control of bacteria or oxygen was attempted. Water injection under the same conditions was then attempted into the light oil column of the 2A zone. Sustained injectivity was very low and the overall well performance was indicative of perforation plugging. From this test it was concluded that insufficient well cleanup due to production facilities not being available coupled with perforations on the low side of a high angle wellbore were the likely cause of the poor injectivity. A second injection test was conducted on well P-14. A lengthy flow period was not possible because facilities were not available. However the wellbore was low angle and the well was perforated with a tubing conveyed gun which allowed for perforations on both the high and low sides of the wellbore. Injection into the light oil column of the same quality water as in Sag Delta 10 still resulted in very low rates. Results of this test indicated that injectivity impairment was not unique to Sag Delta 10 and a plan was implemented to investigate all possible causes. One of the potential causes investigated was low permeability to water due to low water saturations near the wellbore.It was considered that after a significant volume of water was injected and water saturation increased around the wellbore that injectivity would improve. An additional test on P-14 was conducted where low injection rates of 300 to 500 barrels of water per day was sustained for several days. After injection of over 3000 barrels injectivity had not improved. A bottom hole sample at the end of the test contained significant amounts of iron corrosion products. All of the data from the previous tests was carefully analyzed and it was concluded that perforation plugging was occurring and that the most likely causes were: 1) Emulsions formed at the time of perforating and not being cleaned from the wellbore 2) Corrosion products formed by the injection of highly oxygenated seawater. -1- EXHIBIT VII Cleaning of the wellbore by high producing rates for an extended period and deoxygenation of the injected water were considered the solutions to these problems. An injection test on 0-16 was conducted to test these conclusions. The well had been producing for about a month prior to -the test and the rate was increased to about 10,000 bopd a week prior to the test. Injected water was treated with oxygen scavenger and a biocide prior to injection. Injection was established at rates as high as about 5700 bpd at injectivities of 20 bbl per day per psi. However plugging again occurred at higher injection rates ( >4300 bwpd ) and a substantial injectivity drop resulted. Problems related with injection of the oxygen scavenger resulted in less than desired oxygen control. Water subsequently flowed back from the wellbore contained plugging material that appeared to be corrosion products. Analysis of the constituents of the material is not yet complete. As a result of the above tests it has been concluded that oxygen control is probably the most important factor in producing highly injectable water. No further well tests are planned until the seawater injection facilities in the Endicott plant are available which has the capability of extracting oxygen down to 20 parts per billion. -2- Conservation Page 8 September 20, Order No. 202 1984 c) Additional productivity surveys may be required by administrative order if underground waste of hydrocarbons appears imminent. d) Productivity surveys will be submitted to the Commission within 45 days after the date of the survey. Rule 12 FIELD -WIDE 14ATERFLOOD PROJECT. a) A field -wide waterflood project is approved for the pool area. b) The field waterflood project must be started within two years after regular production from the pool has started. c) The waterflood plan will be submitted to the Commission at least three months before actual water injection begins. d) All applications for permits necessary to implement the waterflood project shall be timely submitted for approval. Rule 13 POOL OFFTAKE RATE. a) The maximum calendar quarter average offtake rate from the pool is 125,000 barrels of oil per day. Calendar quarter average offtake rate means the daily average rate determined by dividing the total volume of oil produced in a calendar quarter by the number of days in that calendar quarter. b) The maximum calendar quarter average offtake rate of 125,000 barrels of oil per day may be exceeded for the purpose of making up a shortfall in the allowable volume of oil produced in a previous calendar quarter providing that the offtake rate for any day does not exceed one hundred ten percent (110%) of the calendar quarter average offtake rate. c) For the purpose of providing for reasonable operating flexibility, the calendar quarter offtake volume may be exceeded. The volume of oil determined by multiplying 125,000 barrels by the number of days in that calendar quarter establishes an allowable calendar quarter offtake volume. A calendar quarter offtake volume may not exceed the allowable calendar quarter offtake volume by more than one percent (1.0%) without prior approval of the Commission. Volumes of oil exceeding the allow- able calendar quarter offtake volume shall be zeroed out in the following calendar quarter by producing at rates lower than the maximum calendar quarter average offtake rate until that volume of oil produced in excess of the previous allowable calendar quarter offtake volume is offset. The volume of oil produced in calendar quarters in excess of the allowable calendar quarter average offtake rate for the purpose of recovering a shortfall in an allowable calendar quarter offtake volume as provided for by (b) above is not given consideration when making a determination