The URL can be used to link to this page

Home My WebLink About2011 Northstar Oil PoolZE Emeka Emembolu Head of Base Management, Alaska Strategic Performance Unit March 21, 2012 Dan Seamount Commissioner Alaska Oil and Gas Conservation Commission 333 W. 7th Ave #100 Anchorage, Alaska, 99501-3539 RE: Northstar Field, Northstar Oil Pool Annual Rese Dear Mr. Seamount: BP Exploration (Alaska) Inc. 900 East Benson Boulevard P.O. Box 196612 Anchorage, Alaska 99519-6612 Main 907 564 5111 RErEdVED MAR 2 7 2012 Alaska Oil & Gas Cons.Commission Anchorage it Performance R6port BP Exploration (Alaska) Inc., as operator of the Northstar Unit, hereby submits the attached Annual Reservoir Performance Report in accordance with the requirements of Conservation Order 458A and 20 AAC 25.115. This report covers the period January 1, 2011 through December 31, 2011. The report is organized according to the outline provided in Rule 7 of the conservation order. Item f, Future development plans, and g, Review of Annual Plan of Operations and Development have been combined into a single item titled Review of Annual Plan of Operations and Development and Future Development plans. The final section addresses 20 AAC 25.115. BP reserves the right to alter the content of the analyses contained in this report at any time based upon the most recent surveillance information obtained. Please contact Katrina Cooper (564-5167) or Mark Sauve (564-4660) if there are any questions. Sincerely, Emeka Emembolu Phone:(907) 564-5536 Fax: (907) 564-4440 Email: Emeka.Emembolu@bp.com Web: www.bp.com cc: Jeff Walker, BSEE Kevin Banks, DNR Bob Gage, Murphy R. L. Skillern, BP File Annual Reservoir Performance Report Northstar Field Northstar Oil Pool January 2011 through December 2011 by March, 2012 Table of Contents A. Progress of Enhanced Recovery Project and Reservoir Management Summary B. Voidage Balance by Month of Produced Fluids and Injected Fluids and Cumulative Status C. Summary and Analysis of reservoir pressure surveys within the pool D. Results and Analysis of Production and Injection Log surveys, tracer surveys, observation well surveys and any other special monitoring. E. Review of pool production allocation factors and issues over the prior year F. Review of Annual Plan of Operations and Development and Future Development Plans G. Status of wells shut-in for 365 days or more Attachment 1: Map of Well Locations Attachment 2: Northstar Field 2011 Overview Statistical Summary Attachment 3: Northstar Field 2011 Reservoir Pressure Report, Form 10-412 2 A) Progress of Enhanced Recovery Project and Reservoir Management Summary During 2011, no new wells were drilled or sidetracked in the Northstar Unit. The location of all the wells in the Northstar Unit is shown in Attachment 1. Production and injection statistics are summarized in Attachment 2. Average daily oil production from the Northstar field was 14,387 bopd and average daily gas injection was 524.5 mmscfpd. The reservoir voidage balance values reported do not include oil production from satellite well NS34A or Kuparuk zone production from well NS08. During 2011, gas injection was calculated to be 4,158 thousand -reservoir barrels (MRB) more than reservoir voidage. At year end, the reservoir overall cumulative voidage replacement ratio was 1.017. The average of reservoir pressure control for 2011 was 5,109 psia. 3 B) Voidage Balance by Month of Produced Fluid and Injected Fluids - 2011 2011 Produced Fluids Injected Fluids Not Injection (Injection - Production) Formation Gas, MRB Import Gas, MRB Total Injection, MRB Cum Year since Cum, start-up, MRB MRB Net Injection, MRB Year Cum, MRB Cum 9,124 310 9,434 9,434 928,143 Total -8 since 10,619 796 Free Gas, Water, Voidage, Year start-up, Month Oil, MRB MRB MRB MRB Cum, MRB MRB Jan -2011 909 8,533 360 9,442 9,442 914,282 Feb -2011 974 9,979 414 10,953 20,396 925,236 Mar -2011 1,068 11,191 448 12,259 32,655 937,495 Apr -2011 978 10,544 418 11,522 44,177 949,017 May -2011 924 10,533 439 11,458 55,634 960,475 Jun -2011 781 9,129 403 9,910 65,545 970,385 Jul -2011 726 9,264 412 9,990 75,534 960,375 Aug -2011 772 9,673 429 10,445 85,979 990,819 Sep -2011 727 9,246 389 9,973 95,952 1,000,792 Oct -2011 770 9,419 417 10,188 106,141 1,010,981 Nov -2011 800 9,634 392 10,434 116,574 1,021,415 Dec -2011 759 8,642 400 9,400 125,975 1,030,815 2011 Totals 10,188 115,787 4,920 125,975 Injected Fluids Not Injection (Injection - Production) Formation Gas, MRB Import Gas, MRB Total Injection, MRB Cum Year since Cum, start-up, MRB MRB Net Injection, MRB Year Cum, MRB Cum since start-up, MRB 9,124 310 9,434 9,434 928,143 -8 -8 13,861 10,619 796 11,415 20,849 939,558 462 454 14,323 11,893 714 12,608 33,457 952,166 348 602 14,671 11,190 469 11,658 45,115 963,824 136 938 14,807 11,146 664 11,830 56,945 975,655 373 1,311 15,180 9,644 593 10,238 67,183 985,892 328 1,639 15,508 9,742 875 10,617 77,800 996,509 627 2,266 16,135 10,185 878 11,063 88,863 1,007,572 618 2,884 16,753 9,727 540 10,267 99,130 1,017,839 294 3,178 17,046 9,929 570 10,498 109,628 1,028,337 310 3,488 17,356 10,164 521 10,685 120,313 1,039,022 251 3,739 17,608 9,143 677 9,819 130,133 1,048,842 419 4,158 18,027 122,507 7,625 130,133 4,158 4 C) Summary and Analysis of reservoir pressure surveys within the pool Static bottom hole pressures collected in 2011 are summarized below. Well Date Extrapolated Pressure at -11,100' TVDss Datum, psia Data Source NS08 1/26/11 4428* Other NS08 6/14/11 4339* Other NS08 7/17/11 4312* Other NS08 8/29/11 4270* Other NS08 9/25/11 4261 * Other NS13 3/31/11 5119 Other NS13 6/30/11 5118 Other NS13 9/30/11 5111 Other NS13 10/20/11 5125 Other NS16A 11/16/11 5108 SBHP NS18 11/14/11 5108 SBHP NS19 11/17/11 5052 SBHP NS24 11/16/11 5124 SBHP NS28 3/31/11 5081 Other NS28 6/17/11 5070 Other NS28 8/6/11 5133 SBHP NS28 9/23/11 5145 Other NS28 10/22/11 5141 Other N S30 11/13/11 5056 SBHP NS33 817/11 5151 SBHP N S34A 11/12/111 4984 SBHP " Datum for Kuparuk Reservior is 9000' TVDSS These pressures are graphically represented in the next figure that is a plot of Ivishak pressure by well versus time. These data show a slight increase of reservoir pressures during 2011. The average Northstar field reservoir pressure for 2011 is 5,109 psia, up some 6 psi from the 2010 average. Please note that well NS -34A is a satellite well to the main field and the reservoir pressures reported from NS08 during 2011 are from the Kuparuk Reservoir. A complete listing of data from these surveys is shown in Attachment 3 on the AOGCC Reservoir Pressure Report form. 1.7 Northstar Ivishak Well Pressure Data -NS06 NS07 -X NS08 )K NS09-0-NS12 - --NS13 -NS14 -NS15 NS16 NS17 NS18 NS19 NS20 --X NS21 NS22 NS23 NS24 NS25--m--NS27 -0 NS29 -- -- NS31 - -NS05 -�--NS28 -f-NS11 -* NS30 NS33A 5250 04 a 5200 0 0 0 5150 0 O N 5050 m 5000 N N N N M MM M'V I' � V- to In to U') 0 C0 f0 (0 I— f- I- I-- M M M M O O O O O O O O 999 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O Or - C: L 75 .-. L � r . . .. . 75 �L L 75 �L � � r 2 ►Mr� , N N N N M MM M'V I' � V- to In to U') 0 C0 f0 (0 I— f- I- I-- M M M M O O O O O O O O 999 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O Or - C: L 75 .-. L � r . . .. . 75 �L L 75 �L � � r 2 D) Results and Analysis of Production and Injection log surveys, tracer surveys, observation well surveys and any other special monitoring. No new production/injection profiles were obtained in 2011. The following table summarized these as well as previous profile results. Did not log across entire perforation interval; therfore, unknown contibutions from open zones below logged interval are indicated by -. Gas tracer status: The gas tracer program, initiated in 2004, was concluded in 2008 and no further updates are required for this reporting period. FA Percenta a of flow from/to interval. Blank intervals are not perforated. Well Name Well Type Date LogType Ivishak Shublik D Zone E Ivishak Zone D Ivishak Zone C3 Ivishak Zone C2 Ivishak Zone C1 Ivishak Zone B NS23 Injector 7/13/2003 Memo S/T/P 6 29 13 18 16 18 NS27 Injector 7/21/2004 S/T/P 5 12 19 26 38 NS13 Producer 10/4/2004 S/T/P/G radio/G host 12 59 19 10 NS08 Producer 12/7/2004 S/T/P/Gradio/GhosVDEFT 55 31 9 5 NS09 Producer 12/11/2004 S/T/P/Gradio 54 29 17 0 NS24 Producer 3/26/2005 Memo S/T/P/Gradio 43 57 0 NS24 Producer 3/27/2005 RST/Borax-PNL NS14 Producer 3/29/2005 SiT/P/Gradio/Ghost 55 43 2 NS19 Producer 5/16/2005 Memo S/T/P 100 NS14 Producer 6/26/2005 Memo SIT/P/FCAP 17 45 38 NS06 Producer 6/30/2005 S/T/P/Gradio/Ghost 49 40 11 NS28 Producer 8/20/2005 Memo SIT/P/DEFT/Ghost 100 NS05 Producer 10/7/2005 Memo S/T/P 60 40 0 NS16 Producer 5/5/2006 S/T/P/G radio/G host 43 42 15 NS11 Producer 12/20/2006 Memo S/T/P/D EFT/G host 82 18 NS09 Producer 12/22/2006 S/T/P/Gradio 65 30 5 NS08 Producer 4/10/2007 Memo SIT/P 20 0 27 53 NS24 Producer 4/11/2007 Memo S/T/P 50 50 NS19 Producer 4/24/2007 S/T/P/Gradio/Ghost/DEFT 98 2 NS13* Producer 7/14/2007 Memo S/T/P/Gradio 0 100 NS15` Producer 5/10/2008 Memo S/T/P/Gradio 87 13 NS09 Producer 8/29/2008 Baker Gas/Fluid View NS24 Producer 8/30/2008 Baker Gas/Fluid View NS16A Producer 9/12/2008 S/T/P/Gradio/Ghost/DEFT 100 0 NS16A Producer 9/16/2008 S/T/P/Gradio/Ghost/DEFT 100 0 NS16A Producer 10/21/2008 S/T/P/Gradio/Ghost/DEFT 100 0 NS24 Producer 12/3/2008 S/T/P/Gradio/Ghost 100 0 NS24 Producer 12/5/2008 S/T/P/Gradio/Ghost 0 100 0 NS16A Producer 2/12/2009 S/T/P/Gradio/Ghost/DEFT 100 0 NS05 Producer 2/14/2009 S/T/P/Gradio/GhosVDEFT 73 27 NS19 Producer 4/19/2009 S/T/P/Gradio/Ghost/DEFT 96 4 NS16A Producer 4/20/2009 S/T/P/Gradio/Ghost/DEFT 90 10 NS33A Producer 11/12/2009 Neutron WF log and Memo S/T/P 100 NS05 Producer 11/16/2009 Memo S/T/P/Gradio/GhosVDEFT 70 30 NS30 Producer /2009 Memo S/T/P/Gradio/GhosVDEFT 50 50 NS11 Producer /2009 Memo S/T/P/Gradio/DEFT 80 20 NS21 Producer Memo SIT/P/Gradio/GhosVDEFT 100 NS20 Producer :12/13/2009 /2009 Memo S/T/P/Gradio/GhosVDEFT 50 50 NS22 Producer /2009 Memo S/T/P/Gradio/GhosVDEFT 60 40 NS34A Producer /2009 Memo S/T/P/Gradio/GhosVDEFT 100 NS06 Producer 1 5/4/2010 S/T/P/Gradio/GhosVDEFT 65 30 5 NS06 Producer 10/19/2010 S/T/P/Gradio/GhosVDEFT 0 70 1 30 Did not log across entire perforation interval; therfore, unknown contibutions from open zones below logged interval are indicated by -. Gas tracer status: The gas tracer program, initiated in 2004, was concluded in 2008 and no further updates are required for this reporting period. FA E) Review of pool production allocation factors and issues over the prior year Theoretical production is calculated for each Northstar producing well on a daily basis. A well's theoretical production is calculated using average wellhead flowing pressure and hours on production as follows: n _ hoursproduced Pvhf X 1 — X Qaof — Qtheoretical 24 P hsl Where: hoursproduced = hours on line PWhf = average wellhead flowing pressure PWhs; = shut-in wellhead pressure n = flow exponent Qaof = absolute open flow of well with Pwhf = 0 psi Qtheoretical = theoretical production The input parameters (n, Qaof and PWhs;) for each well are determined from well test data and systems analysis and are reviewed each time new test data becomes available. The actual total production for a day is divided by the summation of the theoretical production from each well to calculate a daily allocation factor. This allocation factor is then multiplied by each well's theoretical production to calculate allocated production. Northstar field allocation factors for 2011 averaged 1.27 for oil, 1.09 for water and 1.03 for gas. 1.1 F) Review of Annual Plan of Operations and Development and Future Development Plans Northstar concluded 2011 with six gas injection wells, twenty-one producing wells and two Class I disposal wells available for utilization. historicai weir count Tor ine Iasi two years are summ Year -lls Year Count Producers Injectors Class I Disposal 1 NS05 NS17 NS10 2 NS06 NS23 NS32 --� 3 NS07 NS25 4 NS08 NS27 5 NS09 NS29 - 6 NS11 NS31 7 NS12 8 NS13 9 NS14A Ct 10 NS15 11 NS16 cV 12 NS18 - 13 NS19 - _ _ 14 NS20 -_ - v- - -- 15 NS21 16 NS22 17 NS24 18 NS28 19 NS30 --- --- - 20 NS33A 21 NS34A 1 NS05 NS17 NS10 2 NS06_ NS23 _ NS32 3 NS07 NS25 4 NS08 NS27 - - -----_ 5 NS09 NS29 6 NS11 NS31 7 NS72 _- 8 NS13 9 NS14A _ r _ 10 NS15 - -- -- 11 NS16 N 12 NS18 - 13 NS19 _ 14 NS20 15 NS21-- 16 NS22 - ^�- 17 NS24 18 NS28 19 20 21 NSM NS33A NS34A _ 17- ----._.__ BSEE wells in bold J arized in the following table. Future Development Plans The possibility that satellite hydrocarbon accumulations may exist within expected drilling reach from the island is recognized. These and locations within the main Northstar Ivishak formation will be the subject of additional future appraisal. As of March 2012 no drilling activities are ongoing at Northstar. The Nabors 33 drilling rig was de -mobilized from Northstar Island during the 2010 barging season. 10 G) Status of Wells Shut-in for 365 days or More (20 AAC 25.115) Producers NS15, NS22 and NS28 were the only wells at Northstar shut-in for all of 2011. Northst8r Sh" We11S 2010 1. Reasons for Well Shut -In A High GOR curently uncompetitive to produce due to facility constraints, no known mechanical problems B High water, currently uneconomic to produce, no known mechanical problems C- Low production rate, no known mechanical problems D. Mechanical Problem E. Other (Specify under comments) 2. Current Mechanical Condition Briefly describe the current mechanical condition including the condition of installed tubing and casing strings. 3. Future Utility 1. Evaluating remedial, sidetrack and/or redrill opportunities 2. Remedial well work planned 3. Long term Shut-in weU/ No immediate plans 4. Suspended well 5. P@Aplanned 6. Other (Specify under comments) 11 Date Shut- Reason for Well Current Mechanical Condition of Future Utility Plans & Sw Name In Shut4n' Welk Posslblildso3 Comments D. Mechanical Secured with down hole mechanical 3. Long term Shut-in/No NS15 Mar -09 Problem plug and BPV immediate plans D. DMechanical Secured with down hole mechanical 3. Long term Shut-in/No NS22 Jun 10 Problem plug and BPV immediate plans NS28 Jan -10 A. High GOR - Operable - no (mown problems 6. Other Evaluating injection conversion potent al Uncom etetive 1. Reasons for Well Shut -In A High GOR curently uncompetitive to produce due to facility constraints, no known mechanical problems B High water, currently uneconomic to produce, no known mechanical problems C- Low production rate, no known mechanical problems D. Mechanical Problem E. Other (Specify under comments) 2. Current Mechanical Condition Briefly describe the current mechanical condition including the condition of installed tubing and casing strings. 3. Future Utility 1. Evaluating remedial, sidetrack and/or redrill opportunities 2. Remedial well work planned 3. Long term Shut-in weU/ No immediate plans 4. Suspended well 5. P@Aplanned 6. Other (Specify under comments) 11 Legend W ell Stares as of 12131/2009 0 Disposal Well Gas Injector Oil Procltcer unit Bomciary Lease Tract Bamdary Ivishak ecur>dary North9tar 4*1100 Well Status Basemap AOGCC Arunml Pdrfonname Report AZor Do1gW1130n Hortmntal Scan' 1"=6,000 ft Dade: 10March, 2010 1 4000 NS2B ,NS08 NS 14A NS13 1:72000 1 inch = 6000 feet 0 4000 8000 0 2 Projection Information: Alaska State Plane Zone 4 Clarke 1866, NAD 1927 12000 n 3 ml D az' 0 (D 3 D 0 O n z O U) X m r r r O n D O z Attachment 2 NQRTHSTAR FIELD 2011 OVERVIEW STATISTICAL SUMMARY WELL STATISTICS As of 12/312011 Full year (1) As of 12/10 (2) Producers 18 14 Injectors 8 6 NOTES: (1) Well court data reflects ONLY those wells which contributed to productionAniection during the respective year (2) Active wells as of December 2011 PRODUCTION/INJECTION STATISTICS Cumulative Start - Up through Production 2011 12/31/11 Oil (BBL) 5,251,424 153,200,201 Gas (MCF) 189,984,768 1,365,132,842 Water (BBL) 5,700,812 39,969,846 Injection Water (BBL) into NS10 & NS32 Disposal Well 6,031,565 43,898,634 Gas (MCF) 191,429,333 1,545,224,905 Balance (excludes satellite well NS -34A and NS08 Kup oil Production Cum Production (MRB) 125,981 1,030,808 Cum Injection (MRB) 130,133 1,048,836 Over/Under (MRB) 4,152 18,028 DAILY AVERAGE RATE DATA 2011 Production Oil, BOPD 14,387 Gas, MCF/D 520,506 Water, BWPD 15,619 Injection Water, BWPD 16,525 Gas, MCFPD 524,464 AVERAGE RESERVOIR PRESSURE Average of surveys obtained in 2011 5109 psia 13 Attachment 3: Reservoir Pressure Report IV, STATE OF ALASKA ALASKA OIL AND GAS CONSERVATION COMMISSION RESERVOIR PRESSURE REPORT 1. Operator BP 1twitk fAlaske live 2. Address: P.O. Bos 196612 Anctkoroc a, AMaka 2MM" 812 3. Unt or Lease Name: Northetw Unit 4. Field and Poot 5. Dalian Reference: Northstar FleflMorthster OB Pool -11,181 6.01 OravNy. 7.O n OravWy: 42 8.79 8, Wel Nome and Number 9. API Mmlber 10. Type 50X10000000IXxX see NO DASHES hstructions 11. AOGCC 12. Zone Pod Code 13. Pertorated 14. Final Test Irtervals Date Top - Bottom TVDSS 15. SW -lin 16. Press. Tmu, Hours Strv. Type (see instnA.tions for codes 17. B.H. 16. Depth Temp. Tool TVDSS 19, Foul Observed Pressure at Tod Depth 20. Dehan 21. Pressure 22. Presse al TVDSS (rgxA) Gradient, psiM Datum (cWVwg NS08 50029230680000 0 590100 Ku aruk 8924-8961 126111 612 Other 197 8634 4342 9000 0.26 4428 NS13 50029230170000 0 590100 Mshak 11055-1109 3/31/11 485 Other 237 10390 4987 11100 0.127 5119 NS28 50029232480000 0 1 590100 Ivishak 11052-1107 3/31/11 10656 Other 242 10480 5004 11100 0.124 5081 NS08 50029230 0 590100 Ku aruk 8924-9961 6/14/11 19 Other 197 8834 4253 9000 0.26 4339 NS13 50029230170000 0 590100 Mshak 11055-1109 6/30/11 1224 Other 238 10390 4986 111001 0.127 5118 NS28 50029232480000 0 590100 Mshak 11052-1107 6/17/11 605 Other 2421 10480 4993 11100 0.124 5070 NS08 500292 680000 0 590100 Ku aruk 8924-8961 7/17111 3d Other 197 8834 4226 9000 0.26 4312 NS33 50029233250100 0 5901 Mshak 25778-2583q 817111 4416 SBHP 136 6841 3980 11100 0.275 5151 NS08 50029230680000 0 590100 Ku aruk 8924-8961 829/11 25 Other 197 8634 41841 9000 0.26 4270 NS00 5002923 00 0 590100 Ku aruk 8924-8951 925111 24 Other 197 6834 4195 9000 0.261 4281 NS13 50029230170000 0 590100 Mshak 11055-1109 9/30/11 288 Other 1 240 10390 4979 11100 0.127 5111 NS28 50029232480000 0 1 590100 Mshak 11052-1107 8rE/11 3B4 SBHP 249 10900 5112 11100 0.104 5133 NM 50029232480000 0 590100 Mshak 11052-1107 923/11 2260 Other 242 10480 5003 11100 0.124 5145 NS13 500292301700CID 0 590100 Ivishak 10924-11 o9c 10/20/111 744 Other 240 10390 49931 11100 0.127 5125 NS16A 50029230960100 0 590100 Mshak 11029-1109 11/16/11 27 SBHP 2531 11000 5096 11100 0.117 5108 NS18 50029231020000 0 590100 Mshak 10977-1104 11/14/11 39 SBHP 250 11000 5097 11100 0.106 5108 NS19 50029231220000 0 1 590100 Mshak 10953-1103 11/17/11 28 SBHP 252 11000 5041 11100 0.105 5052 NS24 50029231110000 0 590100 Mshak 10985-1104 11/15/11 4128 SBHP 250 11000 5113 11100 0.107 5124 NS28 50029232480000 0 590100 Mshak 11052-11 Ggq 1022111 2976 Other 242 10480 4999 11100 0.1241 5141 NS30 50029232930000 0 590100 Mshak 10857-11021 11/13/11 29 SBHP 2531 110001 49621 11100 0.292 5056 NS34A 50029233010100 0 590100 Mshak 11049-11091 11/12/11 30 SBHP 252 11100 4984 11100 0.43 4984 Comments: Surveys kMlcated as *Other" were obtained from Cidra 23. All tests reported hereon were made in accordeoe with the applicable rules, regulations ireructions et the Alaska Oil and Gas Conservation Commission. I hereby certify that the foregoing is true and correct to the best of my knowledge. Signetlre rale Prated Nem" Marls Seaver Date Northstar Lead Production Engineer March 21, 2012 IV,