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Home My WebLink About2021 Prudhoe Oil and Put River Oil PoolsHilcorp Hilcorp North Slope, LLC March 30, 2022 Jeremy Price, Chair 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, 2021— December 31, 2021 Chairman Price, 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, 3411, 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 a o u c. reporting 0 a la ska .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.aarker@hilcorp.com. Thank you, John Barnes Asset Team Leader, Prudhoe Bay East Hilcorp North Slope, LLC Cc: Stephanie Erickson, ConocoPhillips Alaska, Inc. Greg Keith, ConocoPhillips Alaska, Inc. Alex Youngmun, ConocoPhillips Alaska, Inc. Todd Griffith, ExxonMobil Alaska, Production Inc. Jeff Farr, ExxonMobil Alaska, Production Inc. Gary Selisker, Chevron USA Dave Roby, AOGCC Aaron O'Quinn, DNR, Division of Oil & Gas Kevin Pike, DNR, Division of Oil & Gas 3800 Centerpoint Drive, Suite 1400, Anchorage, AK 99503 Phone: 907/777-8300 hilcorp.com 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 2021 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS CONTENTS SECTION PAGE 1.0 INTRODUCTION 4 2.0 OVERVIEW 5 3.0 PRESSURE UPDATE 7 3.1 Pressure Monitoring 3.2 Pressure Plan 4.0 PROJECT SUMMARIES 8 4.1 Prudhoe Waterflood/PBMGP 4.2 Gas Cap Water Injection Project 4.2.1 Observation Well RST Surveys and Zonal Conformance 9 4.2.2 2020 Surveillance Plans 10 4.2.3 Plans for Change in Project Operation 4.3 Put River Pool 11 5.0 GAS MOVEMENT SURVEILLANCE 13 5.1 Gas Movement Summary 6.0 REVIEW OF POOL PRODUCTION ALLOCATION FACTORS 14 2 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS LIST OF EXHIBITS 1-A Prudhoe Bay Unit Field Schematic I-B PBU Well Statistics I-C PBU Production IInjection Statistics I -D PBU Pressure Map I -E Areally Weighted Average Pressure Plot I-F Areally Weighted Pressure Data 1-G Average Monthly CGF MI Rates and Compositions 2 Fieldwide Reservoir Balance 3 Wells Surveyed for Gas Movement 4 Pressure Surveys (Form 10-412) 5-A GCWI Surveillance and Extent 2021 5-B GCWI 2021 Extent: Southwest — Northeast Section 5-C GCWI 2021 Extent: North — South Cross Section 6 Annual Reservoir Properties Report -Prudhoe and Put River Oil Pools (AK 20 AAC 25.270) 7 Put River Sandstone Distribution 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 1.0 INTRODUCTION As required by Conservation Order (CO) 341I and CO 559A, this report provides a consolidated waterflood and gas oil contact report summary of the surveillance activities for the Prudhoe Oil Pool waterflood project, Miscible Gas and Gas Cap injection projects, and the Gravity Drainage Area within the Prudhoe Oil Pool, plus a section for the Put River Pool. The time period covered is January through December of 2021. In keeping with the requirements of the Conservation Orders, the report format provides information for the Prudhoe Bay waterflood / PBMGP FOR project and the gravity drainage project in the field, where applicable. As approved by the AOGCC on March 15, 2021, separate sections for production and injection summaries are not provided for each of the five flood areas within the Prudhoe Oil Pool. However, Exhibits 1-D, 1-E, and 1-F contain pressure analysis for each of the flood areas to provide assurance of sufficient voidage replacement. Information included is as follows: • Analysis of reservoir pressure surveys and trends • Progress of the enhanced recovery projects, including the gas cap water injection project • Voidage balance by month of produced and injected fluids • Data on Minimum Miscibility Pressure (MMP) of injected miscible gas • Summary of Returned Miscible Injectant (RMI) volumes • Results of gas movement and gas -oil contact surveillance efforts • Results of pressure monitoring efforts 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 ao cg c.reporting(a,alaska.gov. A report of completed development or service wells that have been shut-in for 365 days or longer as of January 1, 2021, will be separately filed with the Commission by March 31, 2021, in accordance with 20 AAC 25.115. Production and injection data is provided for the PBMGP project area along with information on the GCWI in the Gravity Drainage region and the Put River Oil Pool. A separate section has been provided with detailed information on gas -oil contact surveillance. As agreed in 2004 with the Commission, the discussion of Gas Production Mechanisms was not included in the report. 12 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 2.0 OVERVIEW Exhibit lA identifies the five flood areas and gravity drainage areas in the Prudhoe Oil Pool as follows: FS-2, EPWZ, WPWZ, NWFB, EWE, and GD. The Waterflood Project encompasses all five flood areas. The Prudhoe Bay Miscible Gas Project (PBMGP) is currently active throughout the waterflood areas. The Eileen West End waterflood pilot concluded in March 1999, after successfully establishing EWE injection potential. EWE information since waterflood startup in September 2001 is included in this report. As previously mentioned, production and injection data is not subdivided into the five flood areas for this report. Exhibits 1-B and 1-C provide well, production, and injection statistics for the Prudhoe waterflood area. The well counts reflect the total number of wells that contributed to production or injection during the report period. During the report period of January through December 2021, field production averaged 161.2 MBOD, 7615.5 MMSCFD (GOR 47241 SCF/STB), and 1214.3 MBWD (water -cut 88.28%). Overall injection during this period averaged 1989 MBWD with 159.87 MMSCFD of miscible gas injection. Exhibit 1-D provides analysis of pressure static, buildup, and falloff data that was collected from 2019 through 2021 at a datum of 8,800 ft, subsea for the Ivishak Formation. 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. 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. We are still investigating the overall benefit of further diluting PBMI, but the current setpoint is still set below the average reservoir pressure in the Prudhoe Bay Miscible Project area. 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 1-G are the monthly average values of analyzer 4901 data. 5 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS The compositions from the analyzers are used to calculate real time MMP at CGF. The MMP data reported in Exhibit 1-G 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. Exhibit 2 provides monthly and annual fieldwide reservoir balance figures. 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). 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 4.3 of this report. A preferred PAVE implementation plan was selected in 2022 for potential implementation in 2023. This would remove up to 300 MBWPD from disposal/waterflood injection for reinjection updip. C: 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 3.0 PRESSURE UPDATE 3.1 Pressure Monitoring Exhibit 4 (Form 10-412) provides pressure, buildup, and falloff data collected in 2021 at a datum of 8,800 ft, subsea used for the Ivishak Formation. During 2021, 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 4 as "FL". Inclusion of the reasonable surface calculated data, based on consistency of the results, confirms an elevated pressure area in the Gas Cap associated with the GCWI project. 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 1-D. 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 413, 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. The excluded pressure measurements are listed separately in Exhibit 4. 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. 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 1-D illustrates the 2021 pressure map using 2019 through 2021 data points. As shown in Exhibit IE, the historic pressure decline appears to have stabilized due to gas -cap water injection and we are starting to see reservoir pressure increase. For 2021, average pressure in the PBMGP project areas using three years of pressure static measurements was calculated to be 3412 psia by areal weighting, as compared to 3404 psia in 2020. The GD area pressure increased 18 psi from 3314 psia in 2020 to 3332 psia in 2021 (Exhibit 1F). 3.2 Pressure Plan Per CO 341I Rule 6a, the following pressure surveillance plan information is provided. Prudhoe Bay reservoir depletion strategies are defined, and the goal of the pressure program is to optimize areal coverage and provide sufficient data for well safety and reservoir management. The plan for 2022 calls for collection of a minimum of 20 pressure surveys fieldwide. In accordance with the rule (5% clause), a minimum of 1 pressure surveys will be collected in each of the seven development areas: Gas Cap, Gravity Drainage, Flow Station 2 Water/MI Flood (MWAG) Project, Eastern Peripheral Wedge Zone MWAG Project, Western Peripheral Wedge Zone MWAG Project, Eileen West End Waterflood Project, and the Northwest Fault Block MWAG Project. Given Commission approval for Seawater Optimization Project (SWOP) and project execution in 7 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 2020, focus will be placed on obtaining pressure measurements in the vicinity of DS-1 and 12 areas in order to monitor changes resulting from waterflood cessation at Flow Station 1. 4.0 PROJECT SUMMARIES 4.1 Prudhoe Waterflood / PBMGP During the report period of January through December 2021, production from the waterflood area averaged 72.1 MBOD, 1588.4 MMSCFD and 1040.9 MBWD. Overall Waterflood injection during this period averaged 1012.3 MBWD with 144.1 MMSCFD of miscible gas injection. The waterflood area's GOR increased from an average of 20,185 SCF/STB in 2020 to an average of 22,030 SCF/STB in 2021. The water cut increased from an average of 92.7% SCF/STB in 2020 to an average of 93.5% in 2021. Cumulative water injection in the five major projects from waterflood startup through December 2021 was 14286 MMSTB, while cumulative MI injection was 3474 BCF. Cumulative production in these same areas (not including Gravity Drainage) since waterflood startup was 3134 MMSTB oil, 16491 BCF gas, and 10714 MMSTB water. As of December 31, 2021, cumulative production exceeded injection by -11516 MMRB compared to -11042 MMRB at the end of 2020. Under - injection is related to production of free gas influxing from the gravity drainage region which should not be replaced so as to maintain a steady declining gas contact. In addition, implementation of SWOP in 2020 resulted in intentional lack of voidage replacement in the flow station 1 waterflood area. Similar to last year, production and injection values have been calculated based upon the waterflood start-up dates for the project areas rather than for each injection pattern. A breakdown of the production and injection data with cumulative figures is provided in Exhibit 1-C for the report period. Interpreted MI breakthrough has occurred in 74 wells during the reporting period. The previous year showed interpreted MI breakthrough in 87 wells. RMI production is an indicator of FOR pattern performance and the presence of RMI is best determined by primarily gas sample analyses that show a separator gas composition richer in intermediate range hydrocarbon components but also proximity to WAG injectors in known MI patterns. MI breakthrough in a WAG pattern well is considered to have occurred when the average RMI rate over the number of producing days in a well exceeds 200 MCF/D. 4.2 Gas Cap Water Injection Project Details of the volume of water injected into the Gas Cap during 2021 are shown below; units in thousands of barrels of seawater injected per month (MBWPM): PSI-01 PSI-05 PSI-06 PSI-07 PSI-08 PSI-09 PSI-10 Total 1/1/2021 3,601 3,330 4,206 3,882 3,375 3,530 3,407 25,330 2/1/2021 2,946 2,783 3,399 3,233 2,820 2,936 2,945 21,063 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 3/1/2021 1 3,530 3,307 4,115 3,842 3,314 3,469 3,349 24,925 4/1/2021 3,356 3,142 3,902 3,636 3,171 3,355 3,131 23,694 5/1/2021 3,410 3,215 3,994 3,618 3,202 3,362 3,189 23,989 6/1/2021 1,114 1,074 1,290 1,154 1,083 942 1,086 7,742 7/1/2021 3,194 3,045 0 3,374 3,054 2,631 2,989 18,285 8/1/2021 2,815 2,614 3,152 3,024 2,648 2,716 2,632 19,602 9/1/2021 3,409 3,190 3,969 3,687 3,195 3,132 3,215 23,796 10/1/2021 3,587 3,340 4,177 3,919 3,322 3,438 3,363 25,145 11/1/2021 2,816 2,638 2,556 2,994 2,653 2,751 2,681 19,090 12/1/2021 3,642 3,376 4,209 3,947 3,404 3,471 3,333 25,382 The 2021 volume of sea water injected in the PSI wells was 258 million barrels. The cumulative volume injected at the end of 2020 was 3.3 billion barrels of sea water since the project startup in 2002. 4.2.1 Observation Cased hole Saturation Logs and Zonal Conformance 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. Many of these wells have had several repeat logs since injection began. By comparing the latest neutron logs with the baseline and previous logs, the presence of injected water can be readily observed. This procedure has provided a very clear picture of water in the Ivishak Formation and allows the monitoring of vertical and lateral movement of the waterfront. Exhibit 5-A is the locator map for the GCWI area and shows the PSI injectors along with the observation wells. The orange polygon indicates the interpreted current GCWI waterfront, which has very minimal change since 2018. The information from all the neutron logs was used to develop the updated northwest -southeast and north -south cross sections (Exhibits 5-13 and 5-C) showing the interpretation of the surveillance data for the current time period. The most recent round of neutron log surveillance included the following wells: 18-02C, 18-03C, and 18-05A. As the areal and vertical extent of the water mass becomes larger, the rate of incremental advancement both laterally and vertically has become noticeably slower. At this point, the changes in the waterfront have followed a relatively predictable pattern established in recent surveillance, where the largest extent of incremental waterfront coverage appeared in Zone 2C, owing to significant lateral continuity of the 24N shale. Surveillance wells for 2021 saturation monitoring were chosen for sufficient coverage to monitor GCW extent, as well as better refine understanding of the water movement into the producing zones I and 1B. Many wells in the DS18 area are producing GCW. Understanding the water pathway to Zone 1, ,i J 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS which is the oil bearing interval in this far upstructure area of the field, is a continued focus for future logging and analysis. Integrating production evidence with log evidence is an important part of the analysis. Future surveillance will continue to include repeat neutron logs for monitoring the maximum lateral extent of the flood front, monitoring water movement within each zone, and specifically in the producing Zone 1. No DS 18 wells started producing GCW for the first time in 2021. 4.2.2 2022 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 with the final timing and locations determined based on the results to date. Gravity Survey A gravity survey is not planned for 2022. 4.2.3 Plans for Change in Project Operation As a result of SWOP implementation and increased operational efficiency at the Seawater Treatment and Injection Plants (STP/SIP), sea water rates greater than the initial project scope of 650 mbwpd (annual average) can be injected. The full field model indicates additional recovery associated with higher injection volumes in the gas cap based on a fieldwide pressure increase. On October 26, 2021, the AOGCC amended C0341J Rule 17, removing GCWI injection rate/volume limits, therefore allowing average injection rates above the previously approved 650 mbwpd. The desired annual average GCWI target volume for 2022 is 750 mbwpd. 10 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 4.3 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). 2021 Production and Injection For the year 2021, all the production was from well 15-41B which has perforations in the Western and Central lobes. Production from the Put River Oil Pool in 2021 averaged 38 BOPD averaged across calendar days. There was no injection in the Southern Lobe of the Put River in 2021. 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 2021 cumulative production for the Put River Oil Pool was 14 MBO, 3 MBW and approximately 1,411 MMSCF formation gas. The full life cumulative production for the Put River Oil Pool through December 31, 2021 was 4.3 MMBO, 9.2 MMBW, and approximately 9.4 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.) 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 are also evaluating the operational feasibility of alternative sources of injection water to satisfy voidage replacement requirements needed to resume production from the PROP. In the meantime, while we evaluate our options, we will continue to monitor the reservoir by obtaining a static bottom hole pressure or fluid level in one of our three Put River Southern Lobe wells in 2021 to observe the pressure behavior during the shut-in period. 11 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS For this report (also for last year's 2020 ASR), the reservoir properties in Exhibit 6 for the PROP pertain to the Southern lobe only. 2021 Pressures Put River Oil Pool affected area pressures taken during 2021 are listed in Exhibit 4. The PROP Southern Lobe pressure obtained in injector 01-08A on 3/1/2021 measured 3,868 PSI at-8,100' SSTVD. The pressure was consistent with the previous year's pressure due to the lack of production or injection in the Southern Lobe in 2021. 2022 Surveillance Plan PROP affected area (Southern Lobe) — A stable pressure trend was observed in 2021 as no production or injection occurred in the Southern Lobe during 2021. Since August 2020, both the producer 02-27A and the injector 01-08A have been shut in since the execution of the SWOP project. A static bottom hole pressure or fluid level survey is planned in 2022 for producer 02- 23A, producer 02-27A, or injector 01-08A to observe the pressure behavior in the Put River Southern Lobe during this period of no injection or production. 12 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 5.0 GAS MOVEMENT SURVEILLANCE The report on gas movement surveillance activities and interpretations provides an overall summary of gas influx movement and summarizes the 2021 gas -monitoring logging program. 5.1 Gas Movement Summary Fieldwide GOC surveillance continues with collection of open -hole and cased -hole logs and monitoring of well performance. In order to monitor gas movement in the reservoir, GOC estimates are made across the field and are based upon the ongoing monitoring program and historical well performance. The central portion of the field, the gravity drainage area (GD) exhibits in some areas almost total influx of the LOC (Light Oil Column). In many areas of the GD, a distinct GOC no longer exists. Rather, the data suggest that there is a continuous gradation of gas saturation throughout this part of the reservoir. Gas influx is essentially absent in the southern peripheral regions as a result of water and WAG injection in the waterflood areas. There are areas downdip of the GDWFI area that are affected by gas. It has become difficult in most parts of the field to define a single current GOC as the surface is commonly broken into a series of oil lenses and gas underruns beneath the shales. The reservoir is better characterized by a description of remaining oil targets. The targets within the GD occur within three general regions: the basal Romeo (Zones 1 & 2A) sands, the inter-underrun sands, and oil lenses within the expanded GOC. Production from the Romeo (Zones 1 & 2A) sands has historically been low compared to the more prolific upper zones. This interval has a lower net to gross, lower permeability and more limited sand connectivity than the rest of the reservoir. These factors impede gas expansion into the Romeo. Underruns beneath shales within the Romeo sands are likely to be local. The inter-underrun sands occur throughout the GD and are characterized by one or more underruns or solution gas pockets segmenting the remaining oil pad. Gas underruns are observed beneath the top of the Sadlerochit reservoir, under Zone 4 shales, and the most regional persistent underruns have developed under the mappable floodplain shales of Tango or Zone 213. Oil within the expanded GOC occurs in lenses above regionally continuous shales. Such lenses have been identified from neutron logs. Many lenses continue to exhibit oil drainage over time, while others appear isolated. Exhibit 3 lists the open and cased -hole neutron logs, as well as RST logs, run in the Prudhoe Oil Pool (POP) during the gas -influx reporting period from January 2021 through December 2021. A total of 22 gas -monitoring logs were run in the POP, all of which were cased -hole as no drilling in the POP occurred in 2021. On July 20, 2016, the Commission modified the neutron log requirements in CO 341F Rule 7 (341F.002 (Corrected)) to provide that either cased or open hole neutron logs are useable to fulfill the minimum requirements of 40 neutron log surveys to be run annually. On January 9, 2018, the commission further modified the neutron log requirements in CO 341F (.007) Rule 7 to have the Annual Reservoir Surveillance Report contain the number and approximate locations of neutron log surveys anticipated for the next calendar year. The 2020 ASR 13 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS committed to a minimum of 15 neutron saturation logs to be run in 2021. For plan year January 1, 2022 until December 31, 2022, a minimum of 15 neutron saturation logs will be obtained with the following approximate distribution: Gas Cap-3, Gravity Drainage-5, Gravity Drainage Waterflood Interaction-5, Downdip Areas Affected by Gas-2. 6.0 Review of Pool Production Allocation Factors Prudhoe Oil Pool (POP) and Put River Oil Pools Monthly Average Oil Allocation Factors: 2021 Oil Allocation Factor Jan 0.90 Feb 0.89 Mar 0.89 Apr 0.89 May 0.89 Jun 0.89 Jul 0.90 Aug 0.91 Sep 0.90 Oct 0.94 Nov 0.93 Dec 0.93 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. These allocation factors range from 0.89 to 0.94. Daily allocation data and daily test data are being retained. 14 N O N �D C Zz C =D O> COM Dm <M m D Zu Z< 00 -uX cC/) �c mm Or r- z -0n Om O�u rm CDT O 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS Exhibit 1-B PBU Well Statistics r- '�1B-11 WELL COUNT BY FIELD AREA WF GD 2020 AOGCC Report Producers 389 409 Injectors 163 57 -WAG 17 3 -Water Only 134 23 -Gas 12 31 2021 Producers 410 415 Injectors 160 54 -WAG 13 2 -Water Only 138 20 -Gas 9 32 Production Well Status in 2021 -Newly Drilled -Sidetracked or Redrilled Gas Injection Well Status in 2021 -Newly Drilled -Sidetracked or Redrilled WAG Injection Well Status in 2021 -Newly Drilled -Sidetrcaked or Redrilled Water Injection Well Status -Newly Drilled -Sidetracked or Redrilled 16 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS Exhibit 1-C PBU Production / Injection Statistics Waterflood Project Area Waterflood Project Area 2021 TOTAL 2020 COMPARE Cumulative Production from WF Start -Up thru 2021 Oil (MMSTB) 3134 3107 Gas (BCF) 16491 15911 Water (MMSTB) 10714 10335 Cumulative Injection from WF Start -Up thru 2021 Water (MMSTB) 14286 13916 MI (BCF) 3474 3422 Cumulative Balance from WF Start -Up thru 2021 Cum Production (MMRB) 28637 27699 Cum Injection (MMRB) 17120 16659 Over/Under (MMRB) -11516 -11042 MI Breakthrough in Producing Wells > 200 mcfd 74 87 AVERAGE RATE DATA2021 Production Oil (MBD) 72.1 78.3 Gas (MMSCFD) 1588.4 1580.5 Water (MBD) 1040.9 987.5 Injection Water (MBD) 1012.3 902.8 Gas (MMSCFD) 144.1 145.9 AVERAGE RESERVOIR PRESSURE (psia) Previous report period: 3404 3369 Current report period: 3412 3404 Estimated Annual Change (psi/yr) 8 35 17 + I Exhibit 1-D I __ Prudhoe P ool 21 I �,_--_------------------ - - -I -- -- _ Ililco°pNorthSlopyLLC Regional Reserovlo Pressure Ma 9 P ----- f.'�I - + NWFB- Gas Cap - EWE 2& =$° J.GD an u r WPWZ - 8 2021 Reservior Pressure at 8800' SS Datum • 2019 SBHP s os9sn 311= � 11 8 31050 psi • 2020 SBHP — — — — _ — ° m° 3,150 - 3 �25 psi ° 2021 SBHP me z.1 ,°' a'• 3�25-3,300 psi 2019 Calculated _ _ ___ _ __--_- EPWZ ufa ' ''' 3,300-3,420 psi from Surface Data �, m 3,420-3,550 psi 2020 Calculated 3,5 50-pal from Surface Data --------------- li �1I i s s 3,fi80 - 3,790 si P _ Calculate from d from Surface Data + + + I-�---- e e 3,190 - 3,890 psi ., Prudhoe Bay _ _+ i 3,890-4,000 psi L _I Unit Boundary �De pletion Polygons -------~----------------- NOTE: Engineered control points have been added to the field perimeter to provide a more accurate contouring - s fV �D C z Z = C OD CO M D <M m 00 -U X C �0 m O O r U) Exhibit 1-E Areal Average Pressure 3900 --W--PBMGP Gravity Drainage 3800 lam 3700 3600 P 3500 5 I A 3400 3300 3200 3100 3000 Dec-82 Jan-87 Jan-91 Jan-95 Jan-99 Jan-03 Jan-07 Jan-11 Jan-15 Jan-19 Jan-23 Jan-27 N O N �D z C z C =D O> co m D <m m D;a z< 00 mX ccn �c G < mm � r Or D r z mn Om O;U rm cn-0 O �J 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS Exhibit 1-F 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 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 20 2021 ANNUAL RESERVOIR SURVEILLANCE REPORT PRUDHOE BAY AND PUT RIVER OIL POOLS 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 3398 3304 3315 3327 3292 3617 3345 Jul-18 3396 3328 3320 3380 3286 3619 3360 Jul-19 3381 3364 3334 3401 3319 3593 3369 Jul-20 3414 3431 3341 3449 3314 3671 3404 Jul-21 3411 3483 3348 3437 3332 3692 3412 21 Exhibit 1-G EOA MI Rate MMP MW Average Monthly Mole% MCFD PSI Mol Wt CO2 C1 C2 C3 IC4 NC4 C5+ 1/1/2021 109,422 3,200 32.57 21.59% 31.40% 20.66% 24.94% 1.10% 0.31% 0.00% 2/1/2021 106,985 3,130 32.54 21.62% 31.32% 20.65% 25.34% 0.86% 0.22% 0.00% 3/1/2021 88,614 3,162 32.64 21.46% 30.98% 20.79% 25.51% 0.98% 0.27% 0.00% 4/1/2021 81,871 3,164 32.67 21.09% 31.22% 20.46% 25.68% 1.13% 0.42% 0.00% 5/1/2021 102,722 3,150 32.73 21.46% 31.45% 20.32% 24.44% 1.49% 0.83% 0.00% 6/1/2021 94,618 3,111 32.66 20.03% 32.65% 19.41 % 24.55% 1.75% 1.60% 0.00% 7/1/2021 11,361 3,174 32.26 19.73% 34.46% 18.32% 24.48% 1.67% 1.34% 0.00% 8/1/2021 116,685 3,110 32.76 20.20% 32.38% 18.92% 25.50% 1.87% 1.14% 0.00% 9/1/2021 117,016 3,255 32.27 20.40% 33.76% 19.40% 23.67% 1.67% 1.10% 0.00% 10/1/2021 93,875 3,233 32.29 20.73% 32.73% 20.15% 24.80% 1.01% 0.57% 0.00% 11/1/2021 127,250 3,211 32.30 21.42% 32.38% 20.63% 24.16% 1.04% 0.38% 0.00% 12/1/2021 133,956 3,250 32.27 21.51% 32.05% 20.77% 24.08% 1.03% 0.35% 0.00% Average 98,698 3,179 32.50 20.94% 32.23% 20.04% 24.76% 1.30% 0.71 % 0.00% WOA MI Rate MMP MW Average Monthly Mole% MCFD PSI Mol Wt CO2 C1 C2 C3 IC4 NC4 C5+ 1/1/2021 156,806 3,194 32.54 21.52% 31.49% 20.63% 24.95% 1.10% 0.31% 0.00% 2/1/2021 146,500 3,196 32.54 21.62% 31.28% 20.77% 25.25% 0.86% 0.22% 0.00% 3/1/2021 141,888 3,186 32.60 21.43% 31.16% 20.73% 25.42% 0.98% 0.27% 0.00% 4/1 /2021 132,112 3,149 32.69 21.32% 30.95% 20.73% 25.52% 1.10% 0.38% 0.00% 5/1/2021 148,625 3,152 32.72 21.46% 31.49% 20.32% 24.40% 1.49% 0.84% 0.00% 6/1/2021 141,966 3,108 32.55 19.90% 33.10% 19.28% 24.40% 1.73% 1.59% 0.00% 7/1/2021 126,431 3,128 32.46 19.35% 33.74% 18.82% 24.65% 1.76% 1.68% 0.00% 8/1/2021 43,660 3,189 32.88 21.45% 31.82% 18.12% 26.69% 1.13% 0.79% 0.00% 9/1/2021 141,284 3,249 32.29 20.32% 33.75% 19.30% 23.83% 1.69% 1.11% 0.00% 10/1/2021 146,098 3,244 32.28 20.70% 32.75% 20.15% 24.85% 1.01% 0.53% 0.00% 11/1/2021 147,832 3,260 32.33 21.33% 32.34% 20.57% 24.28% 1.07% 0.41% 0.00% 12/1/2021 154,182 3,271 32.27 21.50% 32.06% 20.75% 24.14% 1.00% 0.34% 0.00% Average 135,615 3,194 32.51 20.99% 32.16% 20.01 % 24.87% 1.24% 0.71 % 0.00% N O N_ �D Z C z C =D O> 00M Dm <M m Z < 00 mX ccn � C Z] ;p G G mm Or r Z �n Om O;u rM cn-0 O Fieldwide Producing Fluids (MMRB) Oil Free Gas Wate r TOTAL Iniected Fluids (MMRB) Wate r Gas TOTAL Net Injection Volumes = Injection - Production (MMRB) TOTAL Producing Fluids (MMRB) Oil Free Gas Wate r TOTAL Iniected Fluids (MMRB) Wate r Gas TOTAL Net Injection Volumes = Injection - Production (MMRB) TOTAL January February March April May June 6.9 6.2 6.9 6.5 6.5 6.1 220.9 193.1 217.0 202.6 206.1 185.9 41.0 37.3 40.5 38.7 36.7 36.9 268.8 236.6 264.4 247.8 249.4 228.9 63.0 56.2 62.8 60.0 58.5 41.7 216.5 188.9 212.2 198.7 201.7 184.0 279.5 245.0 275.0 258.7 260.2 225.7 10.8 8.4 10.6 10.9 10.9 -3.2 Jar August September October November December Totals 5.6 6.1 6.1 6.6 6.8 7.0 77.2 172.1 185.5 192.1 196.5 213.0 228.5 2413.4 30.4 36.6 37.9 41.3 40.6 40.6 458.4 208.1 228.2 236.1 244.4 260.3 276.1 2949.1 48.5 54.7 60.2 64.9 57.2 63.8 691.7 170.5 183.5 188.0 191.9 207.6 222.6 2366.1 219.0 238.2 248.2 256.9 264.8 286.4 3057.7 10.9 10.0 12.1 12.4 4.5 10.3 108.7 N O N �D Z C Z � C =D O� CO M D < M m D Z7 Z< 00 -U X C to C < < mm Or r Z � C7 Om O�U rm G7 -U O .0 IV 2021 Drilling # Well Log Date OH/CH I GOC (MD) I GOC (TVDSS) N/A- No IPA Drilling in 2021 Key OH- Open hole log CH- Cased hole log Not present over logged interval all fluid Not present over logged interval all gas 2021 Surveillance # Well Log Date OH/CH GOC (MD) GOC (TVDSS) 1 B-07A 19-Jan-21 CH 10586 8949 2 C-29B 25-Jan-21 CH 12669 8963 3 06-16A 3-May-21 CH 9710 8843 4 06-04B 4-May-21 CH 9387 1 8821 5 J-03 17-Jul-21 CH Not present over logged interval 6 J-06 18-Jul-21 CH 11166 1 8784 7 R-13 20-Jul-21 CH Not present over logged interval 8 E-12A 22-Jul-21 CH 9232 8982 9 K-06D 23-Jul-21 CH 11534 8997 10 N-20A 24-Jul-21 CH 9677 8681 11 H-25A 26-Jul-21 CH 10335 8719 12 Y-01C 28-Jul-21 CH 12466 8781 13 W-27A 31-Jul-21 CH 11095 8684 14 D-20A 3-Aug-21 CH 10114 8821 15 04-23A 4-Aug-21 CH Poor quality log data 16 04-51 24-Nov-21 CH 9975 8588 17 18-02C 25-Nov-21 CH 10510 8368 18 18-03C 26-Nov-21 CH 9282 8527 19 09-38 3-Dec-21 CH Not present over logged interval 20 09-39 6-Dec-21 CH Not present over logged interval 21 18-05A 8-Dec-21 CH Not present over logged interval 22 Z-32C 10-Dec-21 CH 1 11780 8690 ti O N O CD co z m �- a `a �w c) v co 0 m CD Z IV O fV �D Z C z C =D O> 00 m D <M m D;a Z< 00 -U x C Z7 < m O O O r Cn C �J m i- D Z 0 m m a O ZJ N cn Reservior Pressure Report 1. Operator 2. Address: Hilcorp North Slope, -LC. 3800 Centerpoint Dr. 91400, Mchora c, AK 99503 3. Unit or Lease Name: 4. Field and Pool: 5. Datum Reference: 6. Oil Gravity: 7. Gas Gravity. Prudhoe Bay Unit Prudhoe Bay Field, Prudhoe Oil Peel 8800 TVDss 0.9 SGr27' API .9 16. Press. 19. Final 9. API Number 10. Type Surv.Type Observed 8. We11 Name SWO0O0O00O000( See 11. AOGCC 14. Final 15. Shut-in (see instructions 17. B.H. 18. Depth Tod Pressure at 20. Datum 21. Pressure 22. Pressure and Number: NO DASHES Instructions Pool Code 12. ZDne 13. Perforated Intervals To Boecm TVDSS Test Data Time Hours for codes) Temp. TVDSS Tool Depth TVDSS (input) Gradient int. at Datum cal 8986-9016,9032-9042,8995-9002.8962-8970,9016- 9017,8941-8949,8986-9002,9002-9016,8712- 01-20 50029208210000 O 640150 8726,8986-8995 11/16/2021 3,948 SBHP 193.4 8,800 3,293 8,800.0830 PSVFT 3292.63 9052-9053,9061-9063,9048-9048,8741-8754,9057- 9059,9056-9057,9055-9056,8989-8993,9046- 01-32A 50029216220100 O 640150 9048,9059-9061,9053-9055 11/16/2021 834 SBHP 192 8,800 3,252 8,800.4299 PSVFT 3252.19 9033-9028,9018-9004,90259023,9026-9032,9024- 02-14B W029204460300 O .1. 9025 8895-8898 9029-90249024-9023 5/30/2021 15,086 SBHP 190 8,800 3,033 8,800.3706 PSVFT 3033.09 . Pumped -800 bbls 8917-8938,9191-9208,8787-8804,9277-9283,8960- diesel for freeze 8978,9303-9313,9026-9041,8881-8905,8960- protect and integrity 8981,9123-9140,9148-9161,9254-9270,8978- work so assumed all 03-11 50029203830000 WI 640150 8981,8945-8953,8986-8999,9166-9183,9186-9191 5/24/2021 2,448 FL -64 8,800 diesel in well, but 3579 8874-8843,8834-8832,8829-8826,8342-8365,8872- 05-02A 50029201440100 O 640150 8873 8875-8876 9/13/2021 -7 SBHP 182 8,740 3,237 8,800 A 03 PSVFT 3245.48 O6-038 50029201860200 O 1§40150 8474-8500,9041-9042 903b-9033 8/22/2021 211 SBHP 195 8,800 2,922 8,800.8381 PSVFT 2921.73 8970-8969,8963- 8977,8950-8960,8964-8965,8971- 09-02A 500292019BO100 O 640150 96 8969,83-8958 7/21/2021 239 SBHP 181 8,800 3,141 8,800.4545 PSVFT 3141.1 8775-8776,8783-8783,8757-8760,8763-8763,8783- 8782,8771-8773,8772-8774,8762-8761,8761- 11-06A 50029206740100 O 640150 8771,8778-8779 3/13/2021 67,400 SBHP 154 7,828 2,953 8,800 .3758 PSVFT 3318.25 8810-SM'S913-8930,8812-8813,8940-8959,8848- 8857,8826-8830,8848-8856,8948-8959,8810- 8826,8810-8813,9044-9058,8810-8812,8871- 8879,8838-8848,8830-8838,8813-8821,8887- 8893,8821-8826,8898-8913,8940-8948,8879- 8884,8856-8857,8864-8871,8864-8879,8898- 12-21 50029211010000 WI 640150 8930,8969-8998,8857-8864,9058-9072,8719-8735 9/10/2021 FL 4,292 1,320 8,800. TP = 1320 i 3570 9008-9024,8992-9008,8939-8944,8891-8913,8854- 12-25 5002.210420000 WI 6401. 8883 8751A774 8924-8936,89448981 9032-9048 9/10/2021 FL 3,581 1,250 8,800. TP = 1250 i 3739 8960-8963,8904-8910,9016-9050,8940-8940,8876- 8884,8996-9012,8941-8941,8860-8868,8891- 12-27A 5002921OB10100 WI 640150 8898:8916-8921 9/10/2021 FL 2,009 1,200 8,800. TP = 1200 psi 4219 8975-8994,9006-9057,8993-8994,8853-8868,8975- 12-30 50029218910000 WI 640150 8993,8960-8965 9/10/2021 FL 2,438 1,470 8,800. TP = 1470 i 4344 8777-8776,8804-8799,8795-8793,8859-8865,8398- .0970 PSVFT 8402,8940-8945,8800-8802,87848787,8880- 8926,8800-8801,8802-87978308-8312,8204- 15-21A 150029205030100 O 640150 8230,8960-8968,8793-8800:aa5l-8859,8846-8851 8/21/2021 6,056 SBHP 178 8,1831 3,191 8,8001 3250.89 .1012 PSIV SECOND SET OF GAUGES STOP 9009-9010,9012-9018,9021-9023,9025-9018,9020- 9150, PSI2890, 9021,9026-9029,9025-9027,9033-9033,8412- TEW 172 STOP C-36A 50029217900100 O 640150 1 8434,9030-9027,9022-9022,8434-8457 6/3/2021 99 SBHP 1 173 8,349 2,890 8,800 9096 PSI 2935.59 9028-9027,9027-9027,9027-9024,8512-8536,9024- D-22C 50029207370300 O .1. 9023 4/16/2021 1,022 SBHP 209 8,800 3,346 8,800.4684 PSVFT 3346.04 9065-9067,8520-8530,9061-9059,9049-9055,9055- .0622 PSVFT F-46A 150029221220100 O 640150 9061,9057-9058,9066-9063 4/16/2021 1,105 SBHP 178.8 8,448 2,496 8,8001 2517.89 .5679 PSVFT 8824-8839,8844-8852,883"940,8886-8896,8795- 100292157500DO 8796,8880-8896,8792-8795,8832-8839,8776- 8789,8956-8990,8792-8796,8864-8872,8824- H-21 O 640150 8832,8880-9886,8803-8816 8/3/2021 10,464 SBHP 213 8,721 3,243 8,800 3287.84 .4400 PSVFT J-22A 50029216980100 O 640150 8992-8999,8973-8987,9010-9023,8954-8961 9/1/2021 3,653 SBHP 208.05 8,800 3,239 8,800 3239.02 . Assume gas above 8932-8953,8832-8844,8702-8779,9002-9030,8987- FL. 70 bbls dead 8989,8702-8739,8789-8820,8830-8832,8928- crude FP at 0.38- 8932,8928-8953,8832-8847,88448847,8905- 1Remaining 8921,8874-8895,8820-8824,8953-8987,8739- column is produced Iv}14 50029205120000 WI M150 8779,8779-8782 1 12/27/2021 74,112 FL 1 -56 50 8,W0 water 0.4 3473 . Assume gas above FL. 30 bbls dead crude FP at 0.38- psi/R. Remaining 8784-8W3,8824-8829,8700-8705,8756-8776,8687- column is produced N-27 50029233650000 WI 640150 8692,8722-8727 12/13/2021 624 FL -72 50 8,800 water 0.4 3155 .44 psi/ft water gradient, 0.01 psVft gas gradient. No freeze protect. 10 8504-8562,8428-8495,8388-8407,8284-8313,8357- psi WHP, FL at PSI-01 50029231040000 WI 640150 8374,8256-8284 6/26/2021 384 FL .51 8,800 surface. 3905 .44 psi/ft water gradient, 0.01 psVft gas gradient. I4o freeze protect. WHP reading vac, but PSI-05 50029231740000 WI 640150 8347-8357,8528-8567,8357-8386 6/26/2021 384 FL 151 8,800 assume 3869 .44 psi/ft water gradient, 0.01 psVft gas gradient. W freeze protect. WHP 8418-8437,8469-8494,8442-8461,8236-8294,8330- reading vac, but PSI-06 50029230820000 WI 640150 8349,8494-8513,8369-8384 6/26/2021 384 FL -51 8,800 assume 3895 .44 psi/ft water gradient, 0.01 psVft gas gradient. M freeze protect. 20 psi WHP, FL at PSI-07 50029231770000 WI 640150 8503-8530 6/26/2021 384 FL -45 8,800 surface 3912 .44 psi/" water gradient, 0.01 psVft gas gradient. W freeze protect. 10 psi WHP, FL at PSI-08 50029231140000 WI 640150 8422-8539,8364-8384,8229-8287 6/27/2021 408 FL -51 8,800 surface 3906 .44 psi/ft water gradient, 0.01 psVft gas gradient. W freeze protect. WHP 8474-8484,8293-8335,8436-8464,8391-8404,8269- reading vac, but PSI-09 50029230950000 WI 640150 8293,8494-8542,8360-8379 6/27/2021 408 FL -51 8,800 assume 3894 .44 psi/ft water gradient, 0.01 psVft gas gradient. M freeze protect. 30 psi WHP, FL at PSI-10 50029231100000 WI 640150 8358-8381,8287-8344,8478-8497,8413-8457 6/27/2021 408 FL -50 8,800 surface 3898 .5053 PSVFT 8963-8961,8948-8945,8843-8844,8932-8912,8841- 8842,8961-8959,8856-8846,8959-8952,8845- 8847,8879-8932,8908-88% 8967-8965,8965- V-07 50029233720000 O 640150 8963,8945-8932 8952-8948 8944-8979 8948-8948 4/5/2021 13,536 SBHP 234 8,795 3,8171 8,800 3805.25 .4492 PSVFT 8936-8952,8967-8966,8969-8971,8908-8912,8915- V-08 50029235680000 O 640150 8950 8972-8968 8912-8915 8/4/2021 1,641 SBHP 235 8,800 3,797 8,800 3797.05 8899-8906,8909-8933,8975-8981,8880-8888,8955- W-25A 10029218740100 0 640150 8957,8890-8890,8963-8969,8935-8939,8941-8950 7/25/2021 25,952 SBHP 231 8,750 3,543 8,800.4386 PSVFT 3564.92 8988-9022,8780-8798,8806-8849,8857-8884,8973- 8980,8988-8999,8953-8968,8939-8946,9044- W-40 50029217760000 O 640150 9048,9048-9062,8999-9022,8922-8938,8892-8918 7/25/2021 3,101 SBHP 180 8,8001 3,500 8,800.4195 PSVFT 3499.93 8918-8916,8916-8918,8919-8918,8918-8919,8917- 89198913-89198910-8910,8918-8917,8915- Z-07B 50029220460200 0 640150 8910:8913-8917:8926-8937 8/23/2021 1,592 SBHP 233 8,800 3,736 8,800.3495 PSVFT 3735.99 8853-8870,8897-8903,8891-8897,8891-8903,8912- Z-14B 50.1844020. O 640150 8925,8937-8942,8870-8875,8790-8813,8888-8891 6/6/2021 18625 SBHP 228 8,800 3,498 8,800.3001 PSVFT 3498.01 .4577 PSVFT 8873-8892,8923-8929,8904-8917,8959-8962,9014- Z-16A 50029222450100 O 6411150 9021,8894-8900,8936-8950 8/8/2021 10,293 SBHP 229 8,700 3,556 8,800 3601.67 8907-8922,8778-8793,8799-8803,8730-8746,8937- T150 8945,8865-8874,8821-8834,8755-8769,8890- 8897,8849-8858,8793-8799,8834-8837,8809- Z-21A 50029219380100 0 8821,8882-8890,8837-8849 9/512021 13,124 SBHP 232 8,800 3,669 8,800.4197 PSVFT 3668.89 N C) N �D Cz C z C =D O T> CO N m D !!^^ < M m D ZU Z < 00 N C < m O r O O r U) GCWI Surveillance and Extent 2021 fi]2000 8]6000 880000 fi8+000 888000 892000 fi98000 700000 1.- 10.— 11— 11— 720000 ]]4000 N 4 2021 Water Breakthrough GCW positixelogin2021 GCW negative login 2021 pre-2021 Water Breekthratrgh G) Waterlogged pre-2021 (CC� / GCW Extent2005 GCW Extent2008 GCW Extent2011 (D v X GCW Extent 2019 a: N ' GCW Extent2017 Ul GCW Extent2018 IT GCW Exte1x2019 CD GCW Extent2020 N O GCW Extent2021 4 N J Minimaf observedchangeia GCW! aerial extentfrom 2D17- 2021. GCW is slo wlyfAbng zones vertically and moreZIA wellsare breaking water. SeeXSA-A'- )(10 Horrson{bebw asna� AMb�YvptihOW 855e.ua N C) N �D Z C z C =D O T>I 00 N Dm < M m D;a Z < 00 -U X C Cn T�T C N < < mm Or ^^z l J Om O;U �� rr� m Cn V TO N Southwest - Northeast X Section 2021 A Southwest Northeast X GCWI Water First Year Observed Waterflood Water Gas Oil Shale/Low N:G Sag River SS O X ?a m Cn to I z 0 v Co m c� 0 Z IV O N �D C Z C z C =D O� COM Dm <M m z < 00 X C CD C G � mm Or �z mn Om O�U rm CD T O fV Cfl GCWI 2021 Extent: North -South B-B' Cross Section B Northwest Southeast B' PS 40 Ps 7 PS 1 U 3 L9 10 u4m O420 04 M 04 1A -81oo zoo Note: Waterflood injection area is not the focus cf this 8300 interpretation. Waterflood water shown here is schematic and for illustrative purpose only. 4400 \ 05W ■ — \7 GOC -8,57 aeoo A700 Methodology: GCWI Zonal Extent interpretation made by Zone for -8800 Z1A, Z113, Z2A, Z26, Z2C, Z3, Z4 using current and historical surveillance logs. If anywater seen via logs or production, zone given a ,. positive GCWI interpretation. -89W Polygons drawn by zone for GCW L extent. Interpretation mapped by polygon/zone into FFM grid, shown 1:20 here. 90DO Exaggeration 0 6 5 3 GCWI Water First Year Observed 0 Waterflood Water P Gas - Oil P Shale/Low N:G ------- I,- Sag River SS n N3 O N X Z3 oa C) 0 (o (D O Z3 IV 0 N �D CZ C Z C =D O> co M Dm M m D ZU 00 X C /� J C V C mm O_D r ZZ Om O�U I— M CD T O W CD STATE OF ALASKA ALASKA OIL AND GAS CONSERVATION COMMISSION ANNUAL RESERVOIR PROPERTIES REPORT 1. Operator: Hilcorp North Slope, LLC 2. Address: 3800 Centerpoint Dme Suite 1400, Anchorage, AK 99503 3. Field and Pool Code: 4. Pool Name 5. Reference Datum (ft TVDSS) 6. Temperature (°F) 7. Porosity (%) 8. Permeability (md) 9. Swi (%) 10. Oil Viscosity @ Original Pressure (cp) 11. Oil Viscosity @ Saturation Pressure (cp) 12. Original Pressure (psi) 13. Bubble Point or Dew Point Pressure (psi) 14, Current Reservoir Pressure (psi) 15. Oil Greuity ('API) 16. Gas Specific G-ity (Air = 1.0) 17. Grass Pay (ft) 18. Net Pay (ft) 19. Original Formation Volume Factor (RB/STB) 20. Bubble Point Formation Volume Factor RB/STB 21. Gas Compressibil ity Factor (Z) 22. Original GOR (SCF/STB) 23. Current GOR (SCF/STB) 640150 Prudhoe Oil 8800 200 22 265 30 0.81 0.81 4335 4335 3390 28 0.77 600 475 1.4 1.4 0.854 730 47,241 640182 Put River Oil 8100 182 19 173 46 1.84 NA 4163 2815 3839 26.9 NA 30 20 1.293 NA NA 548 1,446 I hereby certify that the foregoing is true and correct to the best of my knowledge. Signature Leah Droeae rile Reservoir Engineer 3/22r2022 rioted Name Leah Droege Date 1. m C0 (D O O a CI) CD co N CD O fV O N �D CZ C z C =D coO> W N Dm <M m D Zu Z < 00 -U X C W --�C ram Or D r Z C7 Om O�u rm WT O w N O N_ �D C Z Z �D 0r m� < m >(J) m z < CL v m a? 00 a c C J m N Z7 CD o m m cn O D �z C Om O �u rm CDO