The URL can be used to link to this page

Home My WebLink About2024 Schrader Bluff Oil Pool2024 Annual Reservoir Surveillance Report Nikaitchuq Schrader Bluff Oil Pool (NSBOP) Nikaitchuq Field April 3, 2025 Hilcorp Alaska – WNS Asset Team Table of Contents SUBJECT PAGE 1.0 Progress of the Enhanced Recovery Project ............................................................................1 2.0 Results and Analysis of Reservoir Pressure Surveys within the Pool .........................................2 3.0 Results and Analysis of Production and Injection Log Surveys, Tracer Surveys, Observation Well Surveys and Any Other Special Monitoring ......................................................................................3 4.0 Review of Pool Production Allocation Factors and Issues Over the Year ...................................3 5.0 Reservoir Management Summary .........................................................................................4 ATTACHMENT A - NSBOP Well Location Map .......................................................................6 ATTACHMENT B - 2024 NSBOP Voidage Balance by Month .................................................7 ATTACHMENT C - NSBOP Pressure Report, Form 10-412 ....................................................8 ATTACHMENT D - NSBOP Annual Reservoir Properties Report, Form 10-428 ......................9 ATTACHMENT E - NSBOP Injection Well Mechanical Integrity Testing (AIO 36, Rule 8) .....10 Hilcorp Alaska – WNS Asset Team Page 1 1.0 Progress of the Enhanced Recovery Project The Nikaitchuq Field (NF) is located offshore in East Harrison Bay, near the Colville River Delta in the Beaufort Sea. The Nikaitchuq Schrader Bluff Oil Pool (NSBOP) development utilizes an onshore gravel pad located at the Oliktok Point Pad (OPP) and the offshore Spy Island Drill site (SID). The onshore development contains standalone multiphase processing facilities. SID is a drilling location from which offshore production is imported via a flowline bundle to OPP. Processed oil sales are exported through a dedicated pipeline tied into the Kuparuk River Unit (KRU) facilities, operated by ConocoPhillips Alaska, Inc. (CPAI), which exports the oil to the Trans- Alaska Pipeline System (TAPS). The Alaska Oil and Gas Conservation Commission (AOGCC) issued pool rules under Conservation Order No. 639 (CO 639) and Area Injection Order 36 (AIO 36) authorizing the injection of fluids for pressure maintenance and enhanced oil recovery in the NSBOP. At the end of 2024, there were 52 active NSBOP development wells, including 29 production (10 OPP, 19 SID) and 24 injection (7 OPP, 17 SID) wells. One injection (OI15-S4) and six producing (SP23, SP28, SP33, SP36, OP09, OP19) wells were shut-in or inactive. Dual lateral wellbores have been completed in 28 of the 35 production wells (8 OPP, 20 SID). Excluding one well, these wells target the OA sand of the NSBOP. One inactive development well, OP19-T1N, was drilled and completed to test the potential of the N sand development. Additionally, two disposal wells (1 OPP, 1 SID) and three Ivishak source water wells (3 OPP) are active in supporting operations. The existing NSBOP wells are shown in Attachment A. In 2024, Eni (as the previous operator) completed 10 rig work overs to change out broken ESPs on NU production wells. Table 1: 2024 Nikaitchuq Field Well Intervention Activities #Well Name Type Location Reservoir Activity Description Date Completed 1 OP03-P05 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 3/20/2024 2 OP09-S01 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 3/9/2024 3 OP09-S01 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 6/4/2024 4 OP18-08 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 7/18/2024 5 SP03-NE2 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 5/23/2024 6 SP18-N5 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 3/25/2024 7 SP23-N3 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 5/9/2024 8 SP23-N3 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 7/14/2024 9 SP42-NE4 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 4/15/2024 10 SP42-NE4 Producer OPP Schrader Bluff ESP Swap Changeout broken ESP 6/10/2024 Hilcorp Alaska – WNS Asset Team Page 2 The annual average daily NSBOP production during 2024 was 13,282 BOPD. Total oil production from the NSBOP during 2024 was 4,848,137 barrels and is 91,216 Mstb since field startup through 2024. The annual average producing GOR and watercut were 132 SCF/STBO and 77%, respectively. The annual average daily NSBOP water injection during 2024 was 83,092 BWPD. Cumulative water injection in the NSBOP during 2024 was 30,444,994 barrels and 246,312,992 barrels since the start of the project. The 2024 annual and cumulative voidage replacement ratios were 1.35 and 1.09, respectively. Attachment B details the 2024 voidage balance for the NSBOP. Under AIO 36 Rule 8, Attachment F summarizes the mechanical integrity testing results and plans for the NSBOP injection wells. 2.0 Results and Analysis of Reservoir Pressure Surveys within the Pool 6 pressure surveys were recorded in 2024 from 6 wells. All 6 were recorded from down hole gauges following ESP failure events. Reservoir management utilizes continuous pressure monitoring in both producers and injectors. In addition to surface gauges measuring tubing pressures, Nikaitchuq oil producers are equipped with downhole ESP gauges, providing both pump intake pressures (PIP) and discharge pressures, which allow real-time bottom-hole pressure (BHP) monitoring. The data are used to optimize production while monitoring signs of sand production, rising water cuts (WC), increasing gas-oil ratios (GOR) and balancing voidage. During extended shut-ins, the BHP data provides valuable surveillance and model input. Water injection targets maximizing voidage replacement and throughput to optimize production and reserves. Consequently, injection pressures target the maximum pressure not to exceed the fracture gradient, which can lead to early breakthrough events and poor flood conformance; injection wellhead pressures, and if available, BHPs are continuously monitored and injection rates adjusted accordingly. Hilcorp Alaska – WNS Asset Team Page 3 3.0 Results and Analysis of Production and Injection Log Surveys, Tracer Surveys, Observation Well Surveys and Any Other Special Monitoring Reservoir surveillance is routinely conducted to monitor well and reservoir performance, recommend operating condition changes, perform rate allocations, propose optimization actions, and address and solve general issues. Production allocations have been performed continuously using well models calibrated with the most recent well tests. Reservoir surveillance and monitoring activities in 2024 for the NSBOP included: Downhole and wellhead pressure and real-time temperature measurements, ESP main performance parameter monitoring (e.g., current, voltage, motor temperature), Corrosion monitoring, Well performance indicative of tubing leaks or failing ESPs, Hydrocarbon and produced water surface sampling, Well production tests. 4.0 Review of Pool Production Allocation Factors and Issues Over the Year Production from all wells producing from the NSBOP is commingled at the surface into a common production line. Theoretical production for individual wells from the pool is calculated daily using well test allocations consistent with CO 639, Rule 8. Wells are tested at least twice per month using Schlumberger Vx multiphase meters. Daily theoretical production per well is calculated based on the last valid well test and the amount of time that the well was on production for a given day: oductionlDailyTheoreticaBOPDxDailyRate dayMinutes Minutes Welltest produced Pr)( 1440  The daily oil allocation factor for the field is calculated by dividing the total LACT meter production for the day by the sum of the theoretical daily production for each well. Subsequently, daily allocated production is assigned to each well by multiplying its theoretical daily production by the daily allocation factor. The average 2024 NSBOP oil allocation factor during Hilcorp operation was 1.01 as detailed in Table 2 below. Hilcorp Alaska – WNS Asset Team Page 4 Table 2: Average Daily Field Allocation Factors for 2024 5.0 Reservoir Management Summary The Alaska Oil and Gas Conservation Commission (AOGCC) issued pool rules under Conservation Order No. 639 (CO 639) and Area Injection Order 36 (AIO 36) authorizing the injection of fluids for pressure maintenance and enhanced oil recovery in the NSBOP.Consistent with the orders, the overall reservoir management objective is to maximize economic recovery and minimize project risks while maintaining the highest environmental and safety standards. The primary recovery mechanism for the field is waterflooding. Producers and injectors have been drilled in pairs, located side by side and completed with horizontal drains in the OA sands. Oil producer and water injector targets are defined based on historical producer-injector waterflood responses, pressure trends, ESP constraints and well integrity limits. Water injection targets maximizing voidage replacement and throughput to maximize production and reserves. Injection pressures target the maximum pressure not to exceed the fracture gradient, which can lead to early breakthrough events and poor flood conformance. The hydrocarbon present in the Schrader Bluff is viscous and has low expansion energy and little potential for gas expansion. Production and recovery are a result of waterflood displacement. Artificial lifting is crucial for well productivity; thus, ESP failures represent one of the most significant risks to NSBOP production. Other considerable risks are tubing, manifold and pipeline leaks due to corrosion. Studies to understand and mitigate these risks are ongoing. This integrity issue continues to negatively affect production, is costly to diagnose and is remediated through the tubing and ESP replacements. Well constraints for injectors and producers are based on historical analog field and well performance, ESP capacity, pressure trends, waterflood pattern behavior, well integrity #Allocation January February March April May June July August September October November 1.03 December 0.99 TOTAL 1.01 Hilcorp Alaska – WNS Asset Team Page 5 conditions and ongoing operations. Individual well, pattern and field performance are routinely reviewed and discussed with the Anchorage, Houston and Milan teams; pump intake targets and injection well rate targets and pressure limits are defined and communicated to the lead field operators along with guidelines to implement changes. The typical minimum pump intake pressure targets 400 to 500 psi at the sand face but is occasionally higher due to pump capacity limits, gas locking at low pressures, sand production, or other performance concerns. The maximum injection pressure limit target for all the wells is below the formation fracture pressure and is continuously monitored by surface wellhead pressures; occasionally, lower injection limits are implemented for diagnostic or operational purposes. Reservoir management activities will continue in the NSBOP with the objective to: Maximize daily volumes and value by optimizing hydrocarbon production; Minimize risk exposure to key producing wells and maintain well integrity; Proactively define and develop mitigation plans related to water production; Proactively acquire reservoir performance data critical to reservoir management and overall recoverable volumes determination; Ensure timely execution of reservoir surveillance plans, workovers, re-completions, and infill drilling; Update current reservoir simulations and studies to reproduce the field behavior; Find cost-effective solutions to optimize production. Individual well and pattern surveillance data will continue to be collected to monitor performance and improve recovery. A simulation model has been maintained and updated to assist reservoir development and flood management decisions in the NSBOP. Hilcorp Alaska – WNS Asset Team Page 6 ATTACHMENT A - NSBOP Well Location Map Hilcorp Alaska – WNS Asset Team Page 7 ATTACHMENT B - 2024 NSBOP Voidage Balance by Month Month Oil, MSTBO Produced Gas, MMSCF Water, MBBL Total Voidage, MRB Year Cum Voidage, MRB Cum Since Start-up, MRB Water Injection, Mstb Water Injection, Mrb Year Cum, Mrb Cum Since Start-up, Mrb Net Injection, MRB Year Cum, MRB Cum Since Start-up, MRB 1/31/2024 444 61 1,373 1,853 1,853 198,887 2,522 2,547 2,547 211,782 694 694 11,042 2/29/2024 398 51 1,274 1,705 3,557 200,592 2,414 2,438 4,985 214,220 733 1,427 11,775 3/31/2024 425 57 1,373 1,833 5,391 202,425 2,603 2,629 7,614 216,849 796 2,223 12,571 4/30/2024 439 56 1,438 1,914 7,305 204,339 2,587 2,613 10,226 219,461 699 2,922 13,270 5/31/2024 436 56 1,510 1,983 9,288 206,322 2,672 2,699 12,925 222,160 715 3,637 13,985 6/30/2024 432 54 1,460 1,928 11,216 208,250 2,572 2,597 15,522 224,757 669 4,307 14,655 7/31/2024 450 55 1,447 1,934 13,150 210,185 2,670 2,696 18,219 227,454 762 5,069 15,417 8/31/2024 440 55 1,477 1,954 15,104 212,138 2,645 2,671 20,890 230,125 717 5,786 16,134 9/30/2024 418 53 1,449 1,902 17,006 214,040 2,544 2,569 23,459 232,694 667 6,453 16,801 10/31/2024 413 55 1,401 1,848 18,854 215,888 2,561 2,586 26,045 235,280 738 7,192 17,540 11/30/2024 438 66 1,317 1,790 20,644 217,678 2,285 2,308 28,353 237,588 518 7,710 18,058 12/31/2024 472 73 1,482 1,992 22,636 219,670 2,372 2,396 30,749 239,984 404 8,114 18,462 2024 Totals 5,205 691 17,001 22,636 30,445 30,749 Produced Fluids Injected Fluids Net Injection Hilcorp Alaska – WNS Asset Team Page 8 ATTACHMENT C - NSBOP Pressure Report, Form 10-412 Hilcorp Alaska – WNS Asset Team Page 9 ATTACHMENT D - NSBOP Annual Reservoir Properties Report, Form 10-428 Hilcorp Alaska – WNS Asset Team Page 10 ATTACHMENT E - NSBOP Injection Well Mechanical Integrity Testing (AIO 36, Rule 8) Well PTD # Status Date of Last Test Result Frequency (Years) Due Date Injecting since MIT due date? OP-I2 (inj)206-144 WINJ 04/19/23 P 4 04/19/27 Yes OI06-05 210-165 WINJ 03/10/23 P 4 03/09/27 Yes OI07-04 210-153 WINJ 04/05/23 P 4 05/05/27 Yes OI11-01 210-106 WINJ 07/07/23 P 2 (AA)07/06/25 Yes OI13-03 211-100 WINJ 05/23/23 P 4 05/23/27 Yes OI15-S4 211-141 WINJ 03/30/22 F 4 03/29/26 Yes OI20-07 211-140 WINJ 04/25/23 P 4 04/25/27 Yes OI24-08 211-130 WINJ 12/05/23 P 2 (AA)12/04/25 Yes SI02-SE6 220-019 WINJ 12/15/21 P 4 12/15/25 Yes SI06-NE1 219-165 WINJ 05/04/23 P 2 (AA)05/03/25 Yes SI07-SE4 214-100 WINJ 02/26/22 P 4 02/26/26 Yes SI11-FN6 213-128 WINJ 08/03/22 P 4 08/03/26 Yes SI13-FN4 212-156 WINJ 04/30/21 P 4 04/30/25 Yes SI14-N6 213-194 WINJ 04/30/21 P 4 04/30/25 Yes SI15-E1 221-111 WINJ 03/13/22 P 4 03/13/26 Yes SI17-SE2 214-041 WINJ 04/30/21 P 4 04/30/25 Yes SI19-FN2 213-043 WINJ 04/30/21 P 4 04/30/25 Yes SI20-N4 212-029 WINJ 04/30/21 P 4 04/30/25 Yes SI25-N2 212-090 WINJ 04/30/21 P 4 04/30/25 Yes SI26-NW2 214-157 WINJ 08/14/21 P 4 08/14/25 Yes SI29-S2 212-006 WINJ 06/26/21 P 4 06/26/25 Yes SI32-W2 213-013 WINJ 04/30/21 P 4 04/30/25 Yes SI34-W6 215-016 WINJ 06/25/23 P 2 (AA)06/24/25 Yes SI35-W4 213-101 WINJ 04/30/21 P 4 04/30/25 Yes SI43-NE3 222-115 WINJ 01/01/23 P 4 01/01/27 Yes