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Home My WebLink About2024 Prudhoe Oil and Put River Oil Pools3800 Centerpoint Drive, Suite 1400, Anchorage, AK 99503 Phone:907/777-8300 hilcorp.com Hilcorp North Slope, LLC March 31, 2025 Jessie Chmielowski & Greg Wilson, Commissioners Alaska Oil and Gas Conservation Commission 333 West 7th Avenue, Suite 100 Anchorage, AK 99501 RE:Prudhoe Bay Unit, Prudhoe and Put River Oil Pools Annual Reservoir Surveillance Report for Water and Miscible Gas Floods Annual Reservoir Properties Reports January 1, 2024 –December 31, 2024 Commissioners, Hilcorp North Slope, LLC, as operator of the Prudhoe Bay Unit, submits the enclosed Annual Reservoir Surveillance Reports for the Prudhoe Bay Waterflood Project, Miscible Gas Project, Gas Cap Water Injection Project, Field Gravity Drainage Area and Put River Oil Pool in accordance with Conservation Orders 341C (originally CO 279), 341D, 341F.007, 341I, and 559A. In addition, Hilcorp North Slope will simultaneously file the Annual Reservoir Properties Reports (ARPs, form 10-428)for the Prudhoe and Put River Oil Pools under this cover and to aogcc.reporting@alaska.gov. The Operators of the Prudhoe Bay Field reserve the right to alter the content of the analyses contained in this report at any time based upon the most recent surveillance information obtained.If you have any questions regarding the reports, please contact Abbie.Barker@hilcorp.com. Thank you, Kyle Koerber Asset Team Leader, Prudhoe Bay East Hilcorp North Slope, LLC Cc:Stephanie Erickson, ConocoPhillips Alaska, Inc. Greg Keith, ConocoPhillips Alaska, Inc. Becky Steen, ConocoPhillips Alaska, Inc. Todd Griffith, ExxonMobil Alaska, Production Inc. Dave Roby, AOGCC Allan Eddy,DNR, Division of Oil & Gas Kenneth Diemer, DNR, Division of Oil & Gas Heather Beat, DNR, Division of Oil & Gas 1 I ANNUAL RESERVOIR SURVEILLANCE REPORT WATER AND MISCIBLE GAS FLOODS PRUDHOE OIL POOL AND PUT RIVER OIL POOL & ANNUAL RESERVOIR PROPERTIES REPORT PRUDHOE AND PUT RIVER OIL POOLS JANUARY THROUGH DECEMBER 2024 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 2 CONTENTS SECTION PAGE 1.0 INTRODUCTION 4 2.0 OVERVIEW 4 3.0 PRESSURE UPDATE 5 4.0 MISCIBLE INJECTANT (MI)6 5.0 PROJECT SUMMARIES 6 5.1 SWOP and PAVE 6 5.2 Gas Cap Water Injection Project 7 5.2.1 Observation Well RST Surveys and Zonal Conformance 8 5.2.2 2025 Surveillance Plans 9 5.2.3 Plans for Change in Project Operation 9 5.3 Put River Pool 9 5.4 N2 Foam Treatment Program 11 6.0 REVIEW OF POOL PRODUCTION ALLOCATION FACTORS 12 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 3 LIST OF EXHIBITS 1-A Prudhoe Bay Unit Field Schematic 2 Fieldwide Reservoir Balance 3-A PBU Pressure Map 3-B Areally Weighted Average Pressure Plot 3-C Areally Weighted Pressure Data 3-D Pressure Survey (Form 10-412) 4 Average Monthly CGF MI Rates and Compositions 5 GCWI Surveillance and Extent 2024 6 Annual Reservoir Properties Report-Prudhoe and Put River Oil Pools (AK 20 AAC 25.270) 7 Put River Sandstone Distribution 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 4 1.0 INTRODUCTION As required by Conservation Order (CO) 341I and CO 559A, this report provides a consolidated report of the surveillance activities and EOR project updates for the Prudhoe Oil Pool, plus a section for the Put River Pool. The time period covered is January through December of 2024. Information included is as follows: •Production and Injection Volumes and Voidage balance by month •Analysis of reservoir pressure surveys and trends •Data on Minimum Miscibility Pressure (MMP) of injected miscible gas •Progress of the enhanced recovery projects, including the gas cap water injection project The Annual Reservoir Properties Report-Prudhoe and Put River Oil Pools is being submitted under cover of this report as Exhibit 6. (AK 20 AAC 25.270). The Excel version is also being submitted electronically to aogcc.reporting@alaska.gov. A report of completed development or service wells that have been shut-in for 365 days or longer as of January 1, 2025, will be separately filed with the Commission by March 31, 2025,in accordance with 20 AAC 25.115. 2.0 OVERVIEW IPA Prudhoe Bay (Permo-Triassic) Reservoir development began in 1968 with the Prudhoe Bay State No. 1 exploratory well. Regular production began in June 1977. Produced water injection began in June 1977, and large-scale water flood for secondary recovery was installed in August 1984.In June 1987,the Prudhoe Bay Miscible Gas Project (PBMGP) was established. In 2002,Gas Cap Water Injection (GCWI) began, with the goal of stabilizing reservoir pressure.Most recently, implementation of the Seawater Optimization Plan (SWOP) in 2020 at Flow Station 1 ceased water injection in a portion of the Prudhoe Bay Waterflood Project. During the report period of January through December 2024,Prudhoe Oil Pool (POP)production averaged 142.7 MBOD,7653 MMSCFD (GOR 53,483 SCF/STB), and 1262 MBWD (water-cut 89.8%).Overall injection during this period averaged 1,916 MBWD with 120 MMSCFD of miscible gas injection.802 Wells contributed to production and 211 wells contributed to injection. PA Average Daily Oil Production (BOPD) Average Daily Water Production (MBWPD) Average Daily Gas Production (MMSCFPD) Oil Production (MBBL) Water Production (MBBL) Gas Production (BSCF) IPA 142,732 1,262 7,653 52,240 461,791 2,794 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 5 PA Total Gas Injection (BCF) Dry Gas Injection (BCF) MI Injection (BCF) Average Daily Water Injection (MBWPD) Average Daily Sea Water Injection (MBWPD) Average Daily Gas Cap Water Injection (MBWPD) IPA 2,592 2,549 44 1916 719.3 700.0 PA Total Active Well Count Active Producer Well Count Active Injector Well Count IPA 1013 802 211 See Exhibit 2 for POP voidage by month. Note –Exhibit 2 does not include aquifer influx as we cannot directly measure this. However,the full field model and water sample data suggest there has been some amount of aquifer influx over time. 3.0 PRESSURE UPDATE Exhibit 3-D (Form 10-412)provides pressure, buildup, and falloff data collected in 2024 at a datum of 8,800 ft, subsea used for the Ivishak Formation. During 2024, per CO 341I, as modified by the Commission on July 20, 2016, use of calculated BHP’s from surface data in injectors are permitted. All of these new data are listed in Exhibit 3-D as “FL”.However, the fluid level calculated pressures have been excluded from the pressure calculation and map, as it has been observed that the fluid level pressures are more subject to error. Previous years have been corrected with this change in the pressure calculation. Exhibit 3-A provides spatial analysis of pressure static, buildup, and falloff data that was collected from 2022 through 2024 at a datum of 8,800 ft, subsea for the Ivishak Formation.This map shows an elevated pressure in the gas cap area as a function of GCWI. As shown in Exhibit 3-B, the historic pressure decline appears to have stabilized due to gas-cap water injection.With increased gas cap water injection volumes and the commencement of PAVE in the end of 2023, we expect to see an increase in average reservoir pressure in 2025.For 2024, average pressure in the PBMGP project areas using four years of pressure static measurements was calculated to be 3343 psia by areal weighting, as compared to 3324 psia in 2023.The GD area pressure remained stable with a calculated value of 3299 psia in 2023 and 3296 psia in 2024 (Exhibit 3-B).Observed changes in pressure appear to be related to statistical variability and sampling locations.Field voidage replacement ratio was 1.01 in 2024 (not including any potential aquifer influx). 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 6 4.0 MISCIBLE INJECTANT (MI) AOGCC Conservation Order No. 341I,Rule 12 (c) specifies that “The minimum miscibility pressure (MMP) of the Miscible Injectant must be maintained at least 100 psi below the average reservoir pressure in the Prudhoe Bay Miscible Project area. When the Operator demonstrates that the reservoir pressure is no longer declining within the Prudhoe Bay Miscible Project Area (as evidenced by reservoir pressure measurements), the MMP may be maintained at or below the average reservoir pressure in the Prudhoe Bay Miscible Project area.” As MMP became the constraint on NGL production in the winter of 2018, and the reservoir pressure has stabilized with the gas cap water injection project, the MMP limit was increased from 3150 psi to 3200 psi in March of 2019 and further increased to 3300 psi early 2022.The average measured MMP was 3286 psi in 2024. The average reservoir pressure in the PBMGP area was above 3300 psi in 2024 as shown in Exhibits 3B and 3C. There are two MI analyzers at Prudhoe Bay CGF (4901 and 4951). Analyzer 4951 is installed at the suction side of the MI compressors and analyzer 4901 is installed at the discharge side of the compressors downstream of the lean gas back blend. Analyzer 4901 was out of calibration from June to September 2020. However, it was repaired in October 2020 and has been functioning normally since then. The compositional data reported in Exhibit 4 are the monthly average values of analyzer 4901 data. The compositions from the analyzers are used to calculate the daily average MMP at CGF. The MMP data reported in Exhibit 4 are the monthly averages based on the daily average MMP calculated at the discharge side of the MI compressors. Engineering judgement is applied to remove some poor data with extremely high or low values. 5.0 PROJECT SUMMARIES 5.1 SWOP and PAVE On March 5, 2020,the Commission approved the Seawater Optimization Project (SWOP) which was implemented in the 2020 plan year in DS-1 and DS-12 of the Eastern Peripheral Wedge Zone (EPWZ)of the waterflood at these pads.The Commission specified the following two conditions: Condition 1 states that BPXA is required to include in the Annual Reservoir Surveillance report for the POP and PROP: “a detailed description of the progress towards returning the PROP to production”.Condition 2 states that the ASR is to also include “the evaluation of the potential to improve ultimate recovery by ceasing water injection elsewhere in the POP”. The SWOP project was implemented August 2020;a description of the Put River Oil Pool plan is included in section 6.3 of this report.A preferred PAVE implementation plan was selected in 2022 and implementation began in 2023.Activity in 2023 and 2024 included the up-hole recompletion of 9 FS2 area Zone 1 water injectors to Zones 2, 3 and 4 and the completion of PAVE1-1 water injector. Collectively, these wells are injecting approximately 180mbwpd of produced water and we are evaluating options to increase injectivity to further increase injection to approximately 200mbw/d in these wells.The PAVE 3-1 was recently drilled at FS3 and 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 7 should begin injection mid-2025 with injection rates around 75mbwpd.Continued evaluation is underway of a new water injection well at GC1 to inject an additional 75mbwd into the original and expanded gas gap. 5.2 Gas Cap Water Injection Project Details of the volume of water injected into the Gas Cap during 2024 are shown below; units in thousands of barrels of seawater injected per month (MBWPM): Month Total GCWI Volume (MBWPM) 1/2024 20,554 2/2024 23,016 3/2024 24,809 4/2024 22,857 5/2024 24,713 6/2024 23,576 7/2024 22,628 8/2024 6,381 9/2024 20,317 10/2024 20,804 11/2024 22,553 12/2024 24,002 The 2024 volume of sea water injected in the PSI wells was 256 million barrels. The cumulative volume injected at the end of 2024 was 4.1 billion barrels of sea water since the project startup in 2002. 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 8 5.2.1 GCWI Surveillance Pulsed neutron logs (RPM, RMT,etc.) run in offset producers continue to be the primary method of monitoring water movement from the Gas Cap Water Injection project; however, new drill wells that intersect the reservoir units of the Ivishak also offer insight into gas-cap water invasion and migration. By comparing the latest neutron logs with the baseline and previous logs, and new drill wells with resistivity data –which can corroborate cased hole neutron observations –the presence of injected water can be assessed. Together, this procedure has provided a clear and evolving picture of injected sea water in the Ivishak to allow for the monitoring of vertical and lateral movement. Exhibit 5 is the locator map for the GCWI area and shows the PSI injectors along with the observation wells.The pink polygon indicates the interpreted current GCWI waterfront. Updated surveillance data include,a recently acquired neutron surveillance log for L2-20 and five coil-tube drill wells (05-13C, 18-13D,18-07D, 18-26C-L1, and L2-29B). The majority of these new drill wells are within the GCWI area, however, 18-07D and 05-13C were informative as their initial build sections are located, respectively, near the western and southern boundaries of the GCWI front. The surveillance log from L2-20, located southwest of the PSI-injectors,indicates that there is water in the lower Ivishak (1A PBU equity zone), but that the unit is not entirely water swept.Based on the petrophysical log data for 05-13C, 18-13D, and 18-26C, and 18-29C-L1, there is evidence of gas-cap water within equity zones 2C-3, 2A, and (+/-) 1B of the Ivishak. L2- 29B kicked out in-zone in the lowermost Ivishak (1A) and identified gas-cap water in the 1A within the newly drilled area. The build/upper slant for 18-07D did not identify gas-cap water in zones 2B, 2A, or 1B; however, the well did not intersect zones 2C-3, which is the main high permeability section for gas-cap water migration. Based on the partial evidence for 18-07D, we interpret that the western limit of gas-cap water is currently at the build location for 18-07D (Exhibit 5).Finally, 05-13C, near the southern waterfront, did encounter water in its build, supporting previous interpretations that the waterfront is south of that well location. Future surveillance will continue to include repeat neutron logs, new drill wells, and analysis of production data to monitor the lateral extent of the flood front and water movement within the Ivishak,and notably how gas-cap water impacts production within zone 1A.From the recent 2024 drill wells with their primary production interval in zone 1A, several have clear evidence of gas- cap water production, including 05-13C,18-26C,18-29C-L1, and L2-29B. 5.2.2 2025 Surveillance Plans GCWI Injectors Injection pressures, rates, and temperatures are recorded for each well every day. Pressure-rate plots will be routinely monitored for changes in injectivity of the wells. Observation Well Cased Hole Saturation Logs This program will continue as it has in the past by running cased hole saturation logs every year 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 9 with the final timing and locations determined based on the results to date. Gravity Survey The most recent gravity survey was conducted in 2023. HEC may consider another gravity survey in the future. 5.2.3 Plans for Change in Project Operation None 5.3 Put River Oil Pool On November 22, 2005,the AOGCC ruled in Conservation Order 559 that the Western, Central and Southern Lobes of hydrocarbon bearing Put River sands would be defined as the Put River Pool and that the Northern Lobe would be included in the Prudhoe Oil Pool.Exhibit 7 displays all four lobes which are in pressure isolation from each other. Additional technical information was previously supplied with the application which led to Conservation Order 559. On December 19, 2019, the AOGCC granted BPXA’s request to: (1) to administratively amend Conservation Order 559A to contract the Put River Oil Pool (PROP) to the area encompassed by the Southern Lobe of the Put River sandstone; (2) to modify rule 18 of CO341H to ensure that the downhole commingling ruled authorization that currently allows downhole commingling of any well in the PROP with the Prudhoe Oil Pool will continue to apply to wells completed within the currently established bounds of the PROP when the affected area of the PROP is contracted; and (3) a gas oil ratio exemption to wells completed in the Central and Western lobes of the Put River sandstone for the purposes of collecting data to develop a reservoir development strategy for those sands in accordance with 20 AAC 25.240(b)(3). 2024 Production and Injection For the year 2024,no production came from the Put River Oil Pool. The last production from the PROP was from the 02-27A win 2020. On 10/28/23 a patch was placed in the 02-27A over the Put River formation and all subsequent production from the well has been from the POP. There was no injection in the Southern Lobe of the Put River in 2024. Cumulative Put River water injection is 14.1 MMBW.All Put River Southern Lobe injection has been from well 01-08A. 01- 08A was shut-in in August 2020 and remains shut-in due to the execution of the SWOP project. As a result of the injector shut-in, the Put River Southern Lobe producer 02-27A was also shut-in. The full life cumulative production for the Put River Oil Pool through December 31,2024,was 4.3 MMBO, 9.2 MMBW, and approximately 9.9 BSCF formation gas.(Note that these cumulative volumes include a technical estimate, based on material balance calculations, of Southern lobe production from a casing leak in 02-27 between 1994-1997. The cumulative gas volume reported in this report is reflective of the best technical estimate of the formation gas production from the PROP; the volume reported in previous ASRs may differ due to accounting for the estimated casing leak volumes and gas lift volumes.) 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 10 Average Daily Oil Production (BOPD) Average Daily Water Production (MBWPD) Average Daily Gas Production (MMSCFPD) Oil Production (MBBL) Water Production (MBBL) Gas Production (BSCF) 0 0 0 0 0 0 Cumulative Oil Production (MMBO) Cumulative Water Production (MMBW) Cumulative Gas Production (BSCF) 4.3 9.2 9.9 Since the commencement of SWOP and the shut-in of all injection at Flow Station 1, options have been evaluated to restore the PROP to production, including drilling, workover, and non-rig wellwork options to allow for resumed injection into the PROP. We will continue to consider the feasibility of alternative sources of injection water to satisfy voidage replacement requirements needed to resume production from the PROP. For this report,the reservoir properties in Exhibit 6 for the PROP pertain to the Southern lobe only. 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 11 2024 Pressures The PROP Southern Lobe pressure obtained in 02-23A on 2/27/24 measured 3,742 PSI at -8,100’ SSTVD. 2025 Surveillance Plan PROP affected area (Southern Lobe)–Due to no production from and no injection into the PROP since 2020, as well as a historic trend of a consistent reservoir pressure around 3,700 psi since 2020, there are no plans for pressure surveillance in 2025. 5.4 N2 Foam Treatment Program In 2022 and 2023 a campaign began to pump water and foam into Gravity Drainage producers and flowback in an attempt to block gas production and reduce producing GORs. Water injection occurred before foam injection. Multiple injection volumes and periods of well testing during flowback proved that GOR suppression was possible and helped inform the optimal injection volume for GOR suppression, on a well-by-well basis.Water injection for GOR suppression has been executed into 8 gravity drainage wells and observed predictable GOR suppression results, which last for a period of about one week. Follow up foam injection has occurred on three wells to date: C-10B, C-22A, and E-24B. Learnings to date demonstrate that foam treatments can be economic if 4 months of lower GOR are achieved creating competitive production as observed in C-10B. E-24B (zone 1A) was the poorest-performing foam treatment so far –lower permeability GD wells appear to be less favorable for foam. C-10B and C-22A are both higher permeability and similar production rate Zone 1B/2A wells, but the foam results were quite different.C-22A GOR suppression lasted 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 12 only about one month. Looking for high-grading clues, however, it looks like the water response from C-22A was also less favorable than that of C-10B. So perhaps water response can be predictive of foam performance.Going forward, more water treatments are planned to help high- grade future foam candidates.A repeat foam treatment on C-10B is being evaluated to optimize foam treatment design in future candidates. 6.0 Review of Pool Production Allocation Factors Prudhoe Oil Pool (POP) and Put River Oil Pools Monthly Average Oil Allocation Factors: 2024 Oil Allocation Factor Jan 0.938 Feb 0.929 Mar 0.927 Apr 0.929 May 0.912 Jun 0.910 Jul 0.913 Aug 0.906 Sep 0.939 Oct 0.934 Nov 0.942 Dec 0.952 The table contains monthly averages of oil allocation factors from the 7 facilities that receive production from these two pools: GC-1 (POP only), GC-2 (POP only), GC-3 (POP only), FS-1 (POP & PUT), FS-2 (POP only), FS-3 (POP only) LPC (POP only).Any days of allocation factors of zero were excluded.Daily allocation data and daily test data are being retained. 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 13 Exhibit 1-A Prudhoe Bay Unit Map 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 14 Exhibit 2 Fieldwide Reservoir Balance Mo n t h Oi l , M R B Wa t e r , MR B Fr e e G a s , MR B To t a l Vo i d a g e , MR B Ye a r C u m , MR B Cu m S i n c e S t a r t - Up , M R B Wa t e r In j e c t i o n , MR B Mi s c i b l e Ga s In j e c t i o n , MR B Le a n G a s In j e c t i o n , MR B To t a l In j e c t i o n , MR B Ye a r C u m , MR B Cu m S i n c e St a r t - U p , MR B Ne t In j e c t i o n , MR B Ye a r Cu m , MR B Cu m S i n c e St a r t - U p , M R B Ja n - 2 4 6, 1 2 9 42 , 0 3 0 21 7 , 3 4 9 26 5 , 5 0 8 26 5 , 5 0 8 10 7 , 3 7 4 , 6 7 0 61 , 4 1 6 3, 2 8 9 20 0 , 3 4 1 26 5 , 0 4 5 26 5 , 0 4 5 95 , 7 8 9 , 1 2 4 ( 4 6 3 ) ( 4 6 3 ) (1 1 , 5 8 5 , 5 4 6 ) Fe b - 2 4 5, 7 8 0 39 , 5 6 6 20 6 , 3 4 4 25 1 , 6 9 0 51 7 , 1 9 8 10 7 , 6 2 6 , 3 6 0 62 , 2 0 7 2, 9 2 9 19 1 , 0 9 9 25 6 , 2 3 5 52 1 , 2 8 0 96 , 0 4 5 , 3 5 9 4, 5 4 5 4, 0 8 3 (1 1 , 5 8 1 , 0 0 0 ) Ma r - 2 4 6, 0 5 1 42 , 1 2 4 21 4 , 9 8 8 26 3 , 1 6 3 78 0 , 3 6 1 10 7 , 8 8 9 , 5 2 3 67 , 7 8 4 3, 0 8 5 19 8 , 9 0 1 26 9 , 7 7 0 79 1 , 0 5 0 96 , 3 1 5 , 1 2 9 6, 6 0 6 10 , 6 8 9 (1 1 , 5 7 4 , 3 9 4 ) Ap r - 2 4 5, 6 5 9 40 , 1 3 0 19 4 , 6 9 3 24 0 , 4 8 1 1, 0 2 0 , 8 4 2 10 8 , 1 3 0 , 0 0 4 62 , 8 4 1 2, 3 4 2 17 9 , 8 0 0 24 4 , 9 8 2 1, 0 3 6 , 0 3 2 96 , 5 6 0 , 1 1 1 4, 5 0 1 15 , 1 9 0 (1 1 , 5 6 9 , 8 9 3 ) Ma y - 2 4 5, 7 2 6 40 , 9 4 9 19 7 , 9 6 9 24 4 , 6 4 4 1, 2 6 5 , 4 8 6 10 8 , 3 7 4 , 6 4 8 65 , 0 2 9 2, 9 1 8 18 3 , 0 2 8 25 0 , 9 7 5 1, 2 8 7 , 0 0 7 96 , 8 1 1 , 0 8 6 6, 3 3 1 21 , 5 2 1 (1 1 , 5 6 3 , 5 6 2 ) Ju n - 2 4 5, 1 2 6 32 , 6 2 5 17 6 , 2 6 0 21 4 , 0 1 1 1, 4 7 9 , 4 9 7 10 8 , 5 8 8 , 6 5 9 55 , 4 3 8 1, 7 3 2 16 4 , 0 9 0 22 1 , 2 6 0 1, 5 0 8 , 2 6 7 97 , 0 3 2 , 3 4 6 7, 2 4 9 28 , 7 7 0 (1 1 , 5 5 6 , 3 1 3 ) Ju l - 2 4 5, 4 2 5 39 , 7 1 8 17 9 , 2 0 2 22 4 , 3 4 5 1, 7 0 3 , 8 4 2 10 8 , 8 1 3 , 0 0 4 61 , 0 4 7 2, 0 2 3 16 6 , 8 7 1 22 9 , 9 4 1 1, 7 3 8 , 2 0 8 97 , 2 6 2 , 2 8 7 5, 5 9 6 34 , 3 6 6 (1 1 , 5 5 0 , 7 1 7 ) Au g - 2 4 5, 3 4 4 39 , 3 4 7 17 2 , 3 1 0 21 7 , 0 0 1 1, 9 2 0 , 8 4 3 10 9 , 0 3 0 , 0 0 5 44 , 4 4 2 1, 6 3 1 16 1 , 3 3 3 20 7 , 4 0 6 1, 9 4 5 , 6 1 5 97 , 4 6 9 , 6 9 3 (9 , 5 9 5 ) 24 , 7 7 1 (1 1 , 5 6 0 , 3 1 2 ) Se p - 2 4 5, 4 3 8 39 , 6 8 5 17 5 , 5 6 9 22 0 , 6 9 2 2, 1 4 1 , 5 3 6 10 9 , 2 5 0 , 6 9 8 59 , 8 4 6 2, 3 9 4 16 2 , 2 0 6 22 4 , 4 4 6 2, 1 7 0 , 0 6 0 97 , 6 9 4 , 1 3 9 3, 7 5 3 28 , 5 2 4 (1 1 , 5 5 6 , 5 5 9 ) Oc t - 2 4 5, 7 7 0 40 , 3 0 1 19 7 , 9 5 6 24 4 , 0 2 7 2, 3 8 5 , 5 6 3 10 9 , 4 9 4 , 7 2 5 59 , 7 7 8 2, 7 1 2 18 2 , 9 0 7 24 5 , 3 9 7 2, 4 1 5 , 4 5 8 97 , 9 3 9 , 5 3 6 1, 3 7 0 29 , 8 9 5 (1 1 , 5 5 5 , 1 8 8 ) No v - 2 4 5, 8 2 2 40 , 5 6 7 20 4 , 7 2 5 25 1 , 1 1 4 2, 6 3 6 , 6 7 7 10 9 , 7 4 5 , 8 3 9 61 , 8 0 3 2, 7 5 2 18 9 , 1 2 5 25 3 , 6 8 0 2, 6 6 9 , 1 3 8 98 , 1 9 3 , 2 1 7 2, 5 6 6 32 , 4 6 1 (1 1 , 5 5 2 , 6 2 2 ) De c - 2 4 5, 9 7 4 40 , 9 1 2 21 5 , 6 0 7 26 2 , 4 9 3 2, 8 9 9 , 1 6 9 11 0 , 0 0 8 , 3 3 1 64 , 2 7 9 2, 9 3 9 19 9 , 7 5 3 26 6 , 9 7 1 2, 9 3 6 , 1 0 9 98 , 4 6 0 , 1 8 8 4, 4 7 8 36 , 9 3 9 (1 1 , 5 4 8 , 1 4 4 ) 20 2 4 T o t a l s 68 , 2 4 4 47 7 , 9 5 3 2, 3 5 2 , 9 7 2 2, 8 9 9 , 1 6 9 72 5 , 9 0 9 30 , 7 4 5 2, 1 7 9 , 4 5 4 2, 9 3 6 , 1 0 9 36 , 9 3 9 (1 3 8 , 7 5 4 , 2 5 2 ) 20 2 4 V R R 1. 0 1 Cu m . V R R 0. 9 0 Pr o d u c e d F l u i d s In j e c t e d F l u i d s Ne t I n j e c t i o n ( I n j e c t i o n - P r o d u c t i o n ) 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 15 Exhibit 3-A Pressure Map 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 16 Exhibit 3-B Areally Weighted Average Pressure Plot Exhibit 3-C Areally Weighted Pressure Data Exhibit 3-C Areally Weighted Average Pressures DATE FS2 EPWZ WPWZ NWFB GD EWE PBMGP Dec-77 3935 4005 4016 3944 3999 3968 Jul-78 3870 3967 3978 3909 3963 3914 Dec-78 3832 3930 3944 3875 3933 3873 Jul-79 3813 3895 3911 3843 3901 3844 Dec-79 3791 3861 3879 3799 3871 3816 Jul-80 3799 3831 3848 3770 3856 3798 Dec-80 3852 3819 3822 3781 3823 3818 Jul-81 3881 3821 3799 3814 3809 3840 Dec-81 3880 3815 3799 3820 3793 3842 Jul-82 3872 3806 3800 3812 3778 3833 Dec-82 3850 3795 3797 3804 3762 3818 Jul-83 3831 3784 3792 3787 3745 3804 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 17 Jan-84 3814 3771 3783 3772 3728 3790 Jul-84 3796 3758 3777 3756 3711 3774 Jan-89 3779 3743 3771 3736 3695 3755 Jul-89 3760 3730 3763 3723 3678 3740 Jan-90 3732 3708 3731 3704 3658 3713 Jul-90 3708 3693 3716 3687 3641 3695 Jan-91 3680 3676 3694 3655 3623 3666 Jul-91 3642 3657 3673 3628 3605 3635 Jan-92 3617 3641 3652 3602 3588 3615 Jul-92 3591 3626 3632 3577 3570 3593 Jan-93 3561 3600 3619 3544 3549 3582 Jul-93 3543 3595 3598 3515 3531 3565 Jan-94 3539 3555 3578 3483 3512 3537 Jul-94 3523 3536 3555 3456 3492 3516 Jan-95 3496 3524 3555 3507 3482 3506 Jul-95 3473 3507 3536 3489 3466 3486 Jan-96 3466 3485 3497 3478 3446 3463 Jul-96 3450 3467 3472 3461 3430 3443 Jan-97 3446 3484 3460 3444 3404 3441 Jul-97 3429 3467 3438 3427 3387 3421 Jan-98 3452 3417 3417 3421 3379 3430 Jul-98 3435 3409 3394 3402 3363 3415 Jan-99 3445 3391 3382 3343 3339 3443 Jul-99 3429 3378 3360 3317 3323 3426 Jan-00 3406 3361 3372 3268 3294 3418 Jul-00 3390 3351 3353 3240 3273 3395 Jan-01 3366 3325 3325 3225 3274 3358 Jul-01 3360 3310 3309 3205 3257 3347 Jan-02 3325 3334 3289 3163 3270 3358 Jul-02 3312 3324 3273 3144 3245 3347 Jan-03 3299 3316 3262 3121 3236 3696 3297 Jul-03 3285 3306 3245 3118 3223 3659 3283 Jan-04 3271 3296 3228 3116 3211 3645 3272 Jul-04 3277 3324 3281 3296 3239 3614 3290 Jul-05 3338 3344 3282 3289 3250 3542 3314 Jul-06 3304 3296 3276 3296 3233 3536 3293 Jul-07 3357 3339 3275 3248 3243 3618 3310 Jul-08 3317 3299 3298 3269 3244 3626 3299 Jul-09 3348 3310 3308 3271 3248 3663 3315 Jul-10 3367 3329 3317 3329 3259 3666 3339 Jul-11 3368 3345 3308 3322 3265 3640 3338 Jul-12 3375 3338 3350 3302 3283 3632 3348 Jul-13 3391 3335 3313 3329 3276 3663 3348 Jul-14 3402 3324 3314 3322 3270 3652 3348 Jul-15 3398 3330 3313 3335 3275 3645 3350 Jul-16 3409 3332 3303 3332 3277 3650 3343 Jul-17 3396 3306 3310 3327 3287 3611 3343 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 18 Jul-18 3375 3330 3313 3363 3281 3600 3347 Jul-19 3370 3342 3296 3441 3292 3693 3358 Jul-20 3370 3342 3296 3441 3292 3693 3358 Jul-21 3316 3316 3326 3378 3275 3690 3331 Jul-22 3340 3290 3270 3342 3271 3587 3312 Jul-23 3361 3257 3277 3385 3229 3640 3324 Jul-24 3366 3340 3287 3385 3296 3614 3343 It was agreed with the commission that the polygon pressures would be calculated differently starting with the 2005 report, than it had in past reports due to the advent of pressure response to gas-cap water injection.That methodology consisted of utilizing only the pressure gathered during the reporting period. Starting with the 2009 report, since the field pressure has stabilized, pressure points from a rolling three-year period were used to construct the pressure map so as to reduce the statistical variation induced by changing year-to-year well sets. Exhibit 3-A illustrates the 2024 pressure map using 2020 through 2024 data points.Four years of data points were used for the 2024 calculation to a lack of pressure surveys in EWE, which will be collected in 2025 at which point a three-year rolling average will be resumed.Fluid level data points have been removed from the analysis this year, as they appeared to introduce too much error. Using the three-year rolling technique improves the statistical validity of the pressure distribution since it roughly triples the number of data points employed versus only using the current year static pressures. As in the past, abnormal pressures, such as pressures taken in fault compartments and in the Sag River Formation have been removed. For this report, as in the past, pressures taken in fault compartments, the Sag River Formation, and in Zone 1 of the G-Pad LPA (Low Pressure Area), which don’t appear to be in good communication with the rest of the reservoir, have been excluded from Exhibit 3-A. Also excluded were wells shut-in less than a week that had not stabilized as compared to offsetting statics. Other wells completed in Zone 1 and Zone 4B, which are in poor communication with the rest of the reservoir and therefore have lower pressures, were still included in the map and calculations if their shut-in times were deemed long enough.Unless otherwise noted, all pressure calculations are areally weighted, bound by the main field original 50' LOC contour, and are referenced to a pressure datum of 8,800' SS. 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 19 Exhibit 3-D Pressure Surveys (Form 10-412) 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 20 Exhibit 4 MI Composition EOA MI Rate MMP MW Average Monthly Mole% MCFD PSI Mol Wt CO2 C1 C2 C3 IC4 NC4 C5+ 1/1/2024 133,814 3,312 32.17 21.73%32.58%20.26%24.61%0.56%0.18%0.01% 2/1/2024 125,167 3,285 32.28 21.89%32.16%20.20%25.06%0.51%0.13%0.00% 3/1/2024 116,234 3,288 32.28 21.92%32.16%20.20%25.07%0.46%0.12%0.01% 4/1/2024 83,822 3,289 32.24 21.72%32.49%19.86%25.20%0.52%0.15%0.01% 5/1/2024 104,784 3,283 32.27 21.61%32.73%19.69%24.67%0.76%0.47%0.00% 6/1/2024 65,381 3,303 32.21 21.43%33.41%19.27%24.02%0.97%0.80%0.01% 7/1/2024 73,201 3,274 32.10 20.24%34.38%18.48%24.69%1.08%1.03%0.01% 8/1/2024 64,331 3,238 32.12 19.82%34.29%18.47%25.13%1.11%1.06%0.01% 9/1/2024 89,489 3,269 32.25 21.07%33.43%19.03%24.43%1.03%0.90%0.00% 10/1/2024 98,074 3,301 32.25 21.81%32.81%19.56%24.67%0.73%0.35%0.01% 11/1/2024 110,752 3,284 32.34 22.02%32.30%19.93%24.63%0.68%0.37%0.01% 12/1/2024 115,575 3,329 32.14 21.85%32.73%20.11%24.56%0.53%0.16%0.00% WOA MI Rate MMP MW Average Monthly Mole% MCFD PSI Mol Wt CO2 C1 C2 C3 IC4 NC4 C5+ 1/1/2024 153,611 3,338 32.07 21.65%32.85%20.39%24.33%0.53%0.17%0.01% 2/1/2024 164,838 3,284 32.26 21.75%32.24%20.22%25.09%0.51%0.13%0.00% 3/1/2024 182,334 3,287 32.28 21.89%32.19%20.19%25.08%0.47%0.13%0.00% 4/1/2024 204,247 3,286 32.26 21.77%32.38%19.96%25.16%0.52%0.15%0.01% 5/1/2024 208,676 3,278 32.29 21.59%32.67%19.74%24.71%0.76%0.47%0.00% 6/1/2024 204,708 3,285 32.25 21.30%33.35%19.24%24.21%0.98%0.84%0.01% 7/1/2024 206,079 3,255 32.16 20.28%34.11%18.56%24.83%1.09%1.03%0.01% 8/1/2024 172,945 3,211 32.20 19.76%34.06%18.48%25.38%1.14%1.09%0.01% 9/1/2024 194,755 3,266 32.27 21.09%33.42%19.01%24.47%1.02%0.90%0.00% 10/1/2024 193,782 3,300 32.26 21.80%32.80%19.56%24.68%0.74%0.36%0.00% 11/1/2024 192,608 3,287 32.33 22.00%32.35%19.93%24.60%0.68%0.38%0.00% 12/1/2024 180,585 3,329 32.14 21.79%32.78%20.10%24.57%0.54%0.17%0.00% MI Rate MMP MW 2024 MCFD PSI Mol Wt CO2 C1 C2 C3 IC4 NC4 C5+ Average 286,620 3,286 32.23 21.41%32.94%19.60%24.74%0.75%0.48%0.00% 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 21 Exhibit 5 GCWI Surveillance and Extent 2023 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 22 Exhibit 6 Annual Reservoir Properties Report-Prudhoe and Put River Oil Pools (AK 20 AAC 25.270) 2024 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 23 Exhibit 7 Put River Sandstone Distribution