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Home My WebLink About2002 Midnight Sun Oil PoolBP Exploration (Alaska), Inc. 900 East Benson Boulevard Post Office Box 196612 Anchorage, Alaska 99519-6612 Telephone (907) 564 5111 May 20,2003 Commissioners Alaska Oil and Gas Conservation Commission 333 West 1h Avenue, Suite 100 Anchorage, AK 99501 Midnight Sun Oil Pool Annual Reservoir Surveillance ReportRE: Dear Commissioners: Enclosed is the Midnight Sun Oil Pool ("MSOP") Annual Reservoir Report as required by Conservation Order 452 for the year 2002. Please call Frank Carini at (907) 564-5740 if you have any questions regarding this report. Sincerely, c:>1,~ -V /1<:::~-- -. Tim Verseput "'-.I\,.~~J- ""'"'-J GPB Gravity Drainage Team Leader Attachments cc:Marc Vela (ExxonMobil) Jim P. Johnson (ConocoPhillips Alaska Inc. P. White (Forest Oil) (ChevronTexaco) RECE JUN 0 2 2003 A\aska Oi\ & Gas Cons. Commission Anchorage Prudhoe Bay Unit 2002 Midnight Sun Oil Pool Annual Reservoir Report This Annual Reservoir Report for the year ending December 31, 2002 is being submitted to the Alaska Oil and Gas Conservation Commission in accordance with Conservation Order 452 for the Midnight Sun Oil Pool. This report summarizes surveillance data and analysis and other information as required by Rule 11 of Conservation Order 452. Progress of Enhanced Recovery Project Implementation and Reservoir Management Summary (Rule 11 a) The objective of the Midnight Sun reservoir management strategy is to manage reservoir development and depletion to ensure greater ultimate recovery consistent with prudent oil field engineering practices. During primary depletion, both producers experienced increasing gas-oil-ratios (GaRs). Consequently, production was restricted to conserve reservoir energy. Produced water injection into the Midnight Sun reservoir commenced in October 2000 and continues to provide pressure support to Midnight Sun. An upgrade to the GC-1 produced water injection pump in 2001 increased injection pressures and rates to 20-25 MBWPD. The objective of water injection is to increase reservoir pressure, reduce GaRs to enable wells to be produced at their full capacity, and maximize areal sweep efficiency. When reservoir pressure is restored to a target range of 3800-4000 psig, a balanced voidage replacement ratio (VRR) will be maintained. There is a risk of oil flux into the gas cap from mid-field water injection. Placement of the wells drilled in 2001 and voidage management in 2002 has minimized this risk. The VRR target of 1.0 to 1.8 should increase reservoir pressure while minimizing resaturation of oil into the gas cap. Adequate reservoir surveillance for monitoring fluid movement will be critical to successful waterflood management. Plans are underway to convert Well E-103 from production to water injection. The Well E-103 conversion will provide an upstructure location of water injection that will enhance pressure support and minimize resaturation of oil into the gas cap region. EOR project evaluations were initiated and progressed through 2002. Preliminary analysis has indicated the high pipeline costs to supply MI to Midnight Sun remains a hurdle that will need to be overcome to undertake an EOR project in this reservoir. Voidage Balance by Month of Produced and Injected Fluids (Rule 11 b) A total of five Midnight Sun wells have been drilled, with the most recent wells drilled in 2001. Midnight Sun producing wells should have a combined rate of approximately 4 -6 MBOPD in 2003. A peak water injection rate of 20-30 MBWPD is expected when Well E-103 is converted to water injection during 2003. Monthly production and injection surface volumes for 2002 are summarized in Table 1 along with voidage balance of produced and injected fluids for the report period. Analysis of Reservoir Pressure Surveys within the Pool (Rule 11 c) Reservoir pressure monitoring is performed in accordance with Rule 8 of Conservation Order 452. A summary of reservoir pressure surveys obtained during the reporting period is shown in Table 2. Results and Analysis of Production & Injection Logging Surveys (Rule 11 d) In 2002, a production survey was completed in Well E-102 (Table 3). Results of Well Allocation and Test Evaluation (Rule 11 e) Results of well allocation and test evaluation for Rule 7(d.) are attached. No other special monitoring was undertaken during the reporting period. Since August 2002, Midnight Sun production allocation has been performed according to the PBU Western Satellite Production Metering Plan. Allocation relies on performance curves to determine the daily theoretical production from each well. The GC-1 allocation factor is applied to adjust the total Midnight Sun production. A minimum of one well test per month is used to check the performance curves and to verify system performance. Future Development Plans and Review of Plan of Operations and Development (Rule 11 f & g) Development plans for the Midnight Sun Oil Pool are set forth in the attached 2003 Plan of Development and Operations for the Midnight Sun Participating Area. Well E-102, located to the south of Well E-100, was drilled as an injection well that would undergo a pre-production period. Well E-102 has been utilized as a producer to date and is being evaluated for conversion to a permanent producer. Well E-103, located to the southwest of Well E-100, was drilled as an up-dip production well. Due to an apparent conduit to the overlying gas cap, Well E-103 was shut-in shortly after being placed on production due to excessive gas production. Current plans are to convert Well E-103 to water injection service during 2003. Well E-104, drilled in the northwest corner of the field, was drilled as an additional injector well. Water injection into Well E-104 is planned to sweep the thin oil column to the nearest updip producer, Well E-102. 2 Table 1 Midnight Sun Monthly Production, Injection, Voidage Balance Summary Month/Yr Cum Oil (stb) Cum Gas (Mscf) Net Reservoir Voidage (Mrb) Oil Prod (stb) Water Prod (stb) Gas Prod (Mscf) Water Inj (stb) 5~-r:008I20)6b;3991 -84 -107 283 127 999 872 472 387 732 353 423 333 Jan-O2 Feb-O2 Mar-O2 Apr-O2~~ Jun-O2 Jul-O2 ~ Sep-O2 Oct-O2 Nov-O2 Dec-O2 216,804 200,533 288,006 271,848 392,851 354,713 262,744 263,455 236,440 252,370 202,813 215,053 3,889 4,975 19,201 33,043 59,062 48,829 66,165 128,794 131,474 164,327 111,215 115,547 237,002 337,153 778,370 597,216 1,462,947 1,419,425 838,813 712,364 1,159,136 730,699 723,287 882,188 447,628 540,606 606,264 609,821 590,456 636,076 494,292 535,468 541,034 605,496 437,897 664,465 ~,241,541 121,097,5521 5,529,547 I 21,875,922 I 5,801,395 122,473,138 I 6. 194.£4~123.936.085l 6 , M 8 ~ 959125] 55:5rof ! 6,811,703 I 26,194,323 I, -.'- 7 .O75.15~__l26.906.687 l 7,311,598128,065.823 I 7,563,968 I 28,796,522 I 7,766,781 I 29,519,8Q9_l 7,981,834 130,401,9971 Assumotions for Production Table: Oil Formation Volume Factor = 1.27 rb/stb Water Formation Volume Factor = 1.03 rb/stb Gas Formation Volume Factor = .84 rb/Mscf Table 2 Reservoir Pressure Surveys !!!!!P 156 154 151 154 Depth (55) 7,892 7,853 7,721 7,89~- Well E-104 E-104 E-104 E-103 Date 2/12/02 2/12/02 2/12/02 5/28/02 ~ SBHP SBHP SBHP PBU Pressure 3,262 3,243 3,187 3.135 Table 3 2002 Injection Profiles 3 MIDNIGHT SUN PARTICIPATING AREA PRUDHOE BAY UNIT STATE OF ALASKA DECEMBER 31, 2002 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA TABLE OF CONTENTS 1. INTRODUCTION 3 2. SUMMARY OF ACTIVITIES AND STATUS 3 2.1. Produced Fluids 3 2.2. Field Development 3 3. DEVELOPMENT PLAN 3 3.1. Surface and Subsurface Aspects 3 3.2. Production Forecasts 5 4. FIGURES 6 FIGURE 1 STRUCTURE MAP ' FIGURE 2 CROSS-SECTION ' FIGURE 3 MONTHLY PRODUCTION AND INJECTION RATES , FIGURE 4 RESERVOIR PRESSURE PLOT , 6 6 7 7 Page 2 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA 1. INTRODUCTION This Plan of Development for the Midnight Sun Participating Area of the Prudhoe Bay Unit has been prepared for submission to the Director, Division of Oil and Gas, Department of Natural Resources, State of Alaska. This document updates the Third Plan of Development, summarizes production activities from January 1,2002 to December 31, 2002, and outlines plans for development of the Midnight Sun Participating Area. Unless otherwise specified, fluid rates and volumes are for this period. 2. SUMMARY OF ACTIVITIES AND STATUS 2.1.Produced Fluids Oil and condensate deliveries to the Trans-Alaska Pipeline System (TAPS) during the report period totaled 3 MMB. This represents an average of 8.2 MSTBD. Field production is influenced predominantly by individual well productivity and tubing hydraulics. Other factors that impact production levels include maintenance and facility downtime, TAPS slowdowns, and marine transportation system constraints. Since startup in October 1998 through December 31, 2002, crude and condensate deliveries to TAPS total 8 MMB. During the report period, gas production totaled 9 BCF. Water production was 1 MMB during the report period, an average of 2.7 MBPD. 2.2.Field Development Three wells were drilled and completed during 2001 -2002, bringing the total of Midnight Sun development wells to five (Wells E-IOO, E-I01, E-I02, E-103, and E-I04 all shown on Figure 1). Well E-102 was drilled as a mid-field well, located to the south of E-IOO. Due to the overlying gas, the updip E-I03 well was drilled to the southwest of E-1 00 as a horizontal well at the base of the reservoir. The third well, E-104, was completed in early 2002 as an additional injection well located in the northwest sector of the field. As requested, an east-west cross-section including newly drilled wells is shown in Figure 2. 3. DEVELOPMENT PLAN Surface and Subsurface Aspects3.1. Development Drilling and Wellwork3.1.1. Drilling of any additional wells or sidetracks will be based on reservoir performance and ongoing technical evaluation. Ongoing surveillance will be done to evaluate watert1ood performance, well integrity, and the necessity for wellwork. Dri//sites and Pipelines3.1.2. Page 3 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA Midnight Sun development uses existing IP A infrastructure of pipelines, roads and pads. Development is from E Pad using high pressure and low-pressure lines from E Pad into Gathering Center No.1. Injection water is supplied from Gathering Center No.1 through an existing IP A pipeline. 3.1.3.Support Facilities Midnight Sun shares North Slope infrastructure with the IP A as needed to support Midnight Sun Operations, minimizing duplication of facilities. These include camp facilities, potable water and waste disposal facilities, shop and maintenance facilities, airstrip, construction pad, storage and warehouse space, oily waste disposal facilities and telecommunications systems. 3.1.4 Production Allocation Through July 31 2002, Midnight Sun production has been allocated in accordance with conditions approved by the Alaska Department of Natural Resources and the Alaska Oil and Gas Conservation Commission. Production allocation for Midnight Sun initially was based on the Prudhoe Bay Unit Satellite Interim Production Metering Plan. This Plan fixed the allocation factor to 1.0. Since August 2002, Midnight Sun production allocation followed the PBU Western Satellite Production Metering Plan, with key provisions as follows: The current WOA allocation technique for flowing wells will be used. Daily production from flowing wells will be based on the flowing tubing pressure and a modified Vogel curve, or equivalent, developed from well tests. The EOA allocation technique for gas-lifted wells will be used in place of the current WOA procedure. Daily production from gas-lifted wells will be based on empirical well performance curves derived from 3-phase flow equations and production well test data, and will be a function of flowing tubing pressure and gas-lift rate. A minimum of one well test per month will be performed on each welL Efforts will be directed towards increasing the availability of the well test separators through improved analysis of well stability test data. All wells flowing to a gathering center (GC) will use that GC's well allocation factor for oil, gas, and water. Improvements to the GC bank oil meters are in progress as part of the oil gathering system leak detection process and will provide improved allocation factors. Zero-rate tests will be performed on all WOA pads and gathering center test banks once a quarter (every three months). If leak rates are not within acceptable tolerances, corrective measures will be taken. Leak rates from the zero-rate test will be used to correct test rates as necessary .Reservoir specific shrinkage factors will be used to correct metered fluids to stock tank barrels. 3.1.5.Waterflood The Midnight Sun Owners have implemented a midfield waterflood. Well E-I00 was converted to produced water injection service in October 2000. Well E-I00 is currently injecting between 15,000 -23,000 bwpd. Well E-I04 also is being used for produced water injection service and has been injecting at rates of between 1,400- 2,500 bwpd. Figure 2 is a chart with monthly Page 4 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA Midnight Sun production and injection rates. Well E-I02, originally drilled as a pre-produced injector, is being evaluated for conversion to a permanent producer during 2003. Well E-I03 is being evaluated for conversion to produced water injection service during 2003, allowing the Voidage Replacement Ratio (VRR) target to exceed 1.0 until the reservoir pressure has been restored to a target range of 3800-4000 psig. Figure 3 shows that reservoir pressure is increasing since watert1ood startup. A balanced VRR will be maintained once reservoir pressure has been restored. 3.1.6.Enhanced Oil Recovery Enhanced recovery techniques such as miscible gas injection will be evaluated in the future for the potential of increasing the ultimate recovery of the Midnight Sun Reservoir hydrocarbons. 3.2.Production Forecasts Crude and Condensate Rates3.2.1. Hydrocarbon liquids production for the year 2003 is expected to be in the range of 5 to 8 MBD Page 5 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA 4. FIGURES Figure 2 Cross-Section West EastE-IO2 E-IOI Page 6 2003 PLAN OF DEVELOPMENT AND OPERATIONS MIDNIGHT SUN PARTICIPATING AREA Page 7