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Home My WebLink AboutO 224Other Order 224 Docket Number: OTH-25-006 Prudhoe Bay Unit Prudhoe Bay Field Polaris Oil Pool 1. February 4, 2025 AOGCC request for information/notice of investigation 2. March 6, 2025 Hilcorp response to request for information/notice of investigation 3. November 5, 2025 AOGCC notice of proposed enforcement action 4. August 14, 2024 Hilcorp response to proposed enforcement action STATE OF ALASKA ALASKA OIL AND GAS CONSERVATION COMMISSION 333 West Seventh Avenue Anchorage Alaska 99501 Re: Unauthorized Injection of Enriched Gas into the Polaris Oil Pool, S-201A (PTD 2190920) and S-210 (PTD 2190570), Condition of Approval Area Injection Order (AIO) 25A ) ) ) ) ) ) ) ) Docket Number: OTH-25-006 Other Order 224 Prudhoe Bay Unit Prudhoe Bay Field Polaris Oil Pool November 24, 2025 DECISION AND ORDER On November 5, 2025, the Alaska Oil and Gas Conservation Commission (AOGCC) issued a Notice of Proposed Enforcement Action (Notice) to Hilcorp North Slope, LLC (Hilcorp) regarding unauthorized injection in the S-201A and S-210 wells. The Notice proposed a $695,600 civil penalty under AS 31.05.150(a).1 Hilcorp timely requested an informal review. That review was held November 12, 2025. Hilcorp also submitted a written no contest response dated November 13, 2025, which AOGCC has considered as part of its informal review process. This decision and order now follow. SUMMARY OF PROPOSED ENFORCEMENT ACTION The Notice identified violations by Hilcorp of: S-201A and S-210 Wells: Hilcorp violated the provisions of Rule 2 (“Fluid Injection Wells”) of AIO 25A, which limited enriched gas injection in the Polaris Oil Pool to three wells (S-215i, W-208i, and W-215i) and provided procedures for obtaining enriched gas injection authority for additional wells. The Notice proposed civil penalties of $695,600 as follows: S-201A Well: - $100,000 - Initial violation (S-201A) unauthorized injection into the Polaris Oil Pool in violation of AIO 25A Rule 2. - $303,600 for 759 days S-201A was operable/injecting enriched gas while unauthorized. S-210 Well: - $100,000 – Initial violation (S-210) unauthorized injection into the Polaris Oil Pool in violation of AIO 25A Rule 2. - $192,000 for 480 days S-210 was operable/injecting enriched gas while unauthorized. 1 AS 31.05.150(a) provides for not more than $100,000 for the initial violation and not more than $10,000 for each day thereafter on which the violation continues. Other Order 224 November 24, 2025 Page 2 of 4 In addition to the imposed civil penalty, the AOGCC has historically required Hilcorp to provide a detailed written explanation as to how it intends to prevent recurrence of this violation. The AOGCC has also historically required Hilcorp to demonstrate to the AOGCC’s satisfaction a more robust regulatory compliance tracking system that addresses all AOGCC-mandated obligations. For these S- 201A and S-210 violations, as a result of a Notice of Investigation (NOI) issued to Hilcorp on February 4, 2025, by the AOGCC, Hilcorp completed an internal investigation that was included in its NOI response to the AOGCC dated March 5, 2025. This included a root cause analysis and corrective actions to prevent recurrence. Thus, the AOGCC will not require an additional written explanation from Hilcorp. The total proposed civil penalty is $695,600. Violations relating to Underground Injection Control Class II practices warrant the imposition of civil penalties. Evidence indicates that Hilcorp was clearly aware of the obligation established under AIO 25A, Rule 2, requiring specific authorization prior to the injection of enriched gas, as reflected in its prior submissions seeking such authorization for other wells before its self-report in December 2024 (see AIO 25A.020, AIO 25A.023, AIO 25A.024, and AIO 25A.025). Hilcorp’s repeated failure to comply with fundamental injection authorization raises the potential for similar behavior with more serious consequences. Hilcorp’s repeated failure to comply with AOGCC rules and regulations combined with ineffective corrective actions, warrant increased civil penalties to deter similar behavior. The factors in AS 31.05.150(g) 2 were considered in determining the appropriate penalty. Mitigating circumstances include the existing PBU Western Operating Area aquifer exemption, no injury to the public or the environment, and Hilcorp’s notification to the AOGCC once Hilcorp determined the well(s) non-compliance(s). INFORMAL REVIEW: Hilcorp met with AOGCC staff on November 12, 2025, to review and discuss the Notice and to provide an update on the status and results of its internal gap-analysis investigation and associated corrective actions. These actions included formation of a Well Integrity Team, training and procedural conformance measures, development of an injectivity-authorization tracking spreadsheet, implementation of quarterly injection-compliance reviews, and designation of a new single point of contact (SPOC) for Miscible Injectant (MI) injection. Hilcorp did not dispute the violations identified in the Notice. FINDINGS AND CONCLUSIONS: Hilcorp’s violations related to its Underground Injection Control Class II operations constitute repeated failures to comply with AOGCC-imposed conditions of approval and failures to obtain prior AOGCC authorization before implementing changes to an approved permit or order. These violations warrant the imposition of civil penalties as proposed in the Notice. In determining the penalty amounts, the AOGCC considered the factors set out in AS 31.05.150(g). The penalties reflect per-day assessments. The AOGCC issues injection orders and drilling and sundry permits for enhanced oil recovery operations with specific conditions designed to ensure that injection activities are conducted safely, protect the environment, and prevent waste. Injection conducted in violation of orders, conditions of approval, or statewide regulations has not been reviewed or approved 2 AS 31.05.150(g) requires AOGCC to consider nine criteria in setting the amount of a civil penalty. Other Order 224 November 24, 2025 Page 3 of 4 by the AOGCC and therefore carries the potential to damage reservoir(s), cause waste of resources, and increase the risk of loss of containment of injected fluids. Hilcorp’s failures to comply with fundamental AOGCC regulatory, Order, reporting, and Sundry Approval requirements raise concern for similar conduct with potentially more serious consequences. In assessing the civil penalty, the AOGCC considered Hilcorp’s compliance history,3 the need to deter similar conduct, the absence of injury to the public or the environment, and Hilcorp’s notification to the AOGCC upon determining the noncompliance. Hilcorp’s corrective efforts and cooperation with the investigation were also taken into account. AOGCC maintains ongoing compliance tracking and periodically conducts audits. Nothing in this Order should be interpreted as assigning any responsibility to the AOGCC for Hilcorp’s violations, nor should it be construed as a basis for reducing the penalty amount associated with days of noncompliance. Since Hilcorp did not dispute the alleged violation in the Notice, the sections titled “Basis for Finding the Violation or Noncompliance” and “Similar Recent Violations” and “Proposed Action” from the Notice is incorporated by reference into this Decision and Order. The AOGCC finds that Hilcorp committed the violations as initially alleged in the Notice and restated in the “Summary of Proposed Enforcement Action” above. Hilcorp has not provided any information that would warrant changing the proposed penalty amount NOW THEREFORE IT IS ORDERED THAT: Hilcorp is assessed a civil penalty in the amount of $695,600 for the violations detailed within this Order. If this Order is not appealed, the fine must be paid within 30 days of issuance. If appealed, the fine will be held in abeyance until the appeal process is complete. In addition to the civil penalty, Hilcorp is required to improve its regulatory compliance by implementing the corrective actions as detailed in the Hilcorp internal investigation reports as emailed to the AOGCC dated March 5, 2025, that included a root cause analysis and actions to prevent recurrence. As an Operator involved in an enforcement action, Hilcorp is required to preserve documents concerning the above action until after resolution of the proceeding. DONE at Anchorage, Alaska and Dated November 24, 2025. Jessie L. Chmielowski Gregory C. Wilson Commissioner Commissioner 3 Most notably, Hilcorp’s recent violation for unauthorized injection in 2024. See Other Order 208. Gregory C Wilson Digitally signed by Gregory C Wilson Date: 2025.11.24 12:14:32 -09'00' Jessie L. Chmielowski Digitally signed by Jessie L. Chmielowski Date: 2025.11.24 13:12:34 -09'00' Other Order 224 November 24, 2025 Page 4 of 4 Fc: Timothy Mayers, (mayers.timothy@epa.gov) US EPA, Region 10 Evan Osborne, (osborne.evan@epa.gov) US EPA, Region 10 Jim Regg, AOGCC Supervisor, Inspections AOGCC Inspectors Jack Lau, AOGCC Sr. Petroleum Engineer Dave Roby, AOGCC Sr. Reservoir Engineer RECONSIDERATION AND APPEAL NOTICE Pursuant to 20 AAC 25.535(d), this order becomes final 11 days after it is issued unless within 10 days after it is issued the person files a written request for a hearing, in which case the proposed decision or order is of no effect. If the person requests a hearing, the commission will schedule a hearing under 20 AAC 25.540. As provided in AS 31.05.080(a), within 20 days after this order becomes final as discussed above, or such further time as the AOGCC grants for good cause shown, a person affected by it may file with the AOGCC an application for reconsideration of the matter determined by it. If the notice was mailed, then the period of time shall be 23 days. An application for reconsideration must set out the respect in which the order or decision is believed to be erroneous. The AOGCC shall grant or refuse the application for reconsideration in whole or in part within 10 days after it is filed. Failure to act on it within 10-days is a denial of reconsideration. If the AOGCC denies reconsideration, upon denial, this order or decision and the denial of reconsideration are FINAL and may be appealed to superior court. The appeal MUST be filed within 33 days after the date on which the AOGCC mails, OR 30 days if the AOGCC otherwise distributes, the order or decision denying reconsideration, UNLESS the denial is by inaction, in which case the appeal MUST be filed within 40 days after the date on which the application for reconsideration was filed. If the AOGCC grants an application for reconsideration, this order or decision does not become final. Rather, the order or decision on reconsideration will be the FINAL order or decision of the AOGCC, and it may be appealed to superior court. That appeal MUST be filed within 33 days after the date on which the AOGCC mails, OR 30 days if the AOGCC otherwise distributes, the order or decision on reconsideration. In computing a period of time above, the date of the event or default after which the designated period begins to run is not included in the period; the last day of the period is included, unless it falls on a weekend or state holiday, in which event the period runs until 5:00 p.m. on the next day that does not fall on a weekend or state holiday. From:Coldiron, Samantha J (OGC) To:AOGCC_Public_Notices Subject:[AOGCC_Public_Notices] Other Order 224 (Hilcorp) Date:Monday, November 24, 2025 1:53:54 PM Attachments:OTHER224.pdf Unauthorized Injection of Enriched Gas into the Polaris Oil Pool, S-201A (PTD 2190920) and S-210 (PTD 2190570), Condition of Approval Area Injection Order (AIO) 25A Samantha Coldiron AOGCC Special Assistant Alaska Oil and Gas Conservation Commission 333 West 7th Avenue Anchorage, AK 99501 (907) 793-1223 __________________________________ List Name: AOGCC_Public_Notices@list.state.ak.us You subscribed as: samantha.coldiron@alaska.gov Unsubscribe at: https://list.state.ak.us/mailman/options/aogcc_public_notices/samantha.coldiron%40alaska.go v 4 Hilcorp North Slope, LLC Vanessa Hughes, PBW Asset Team Lead 3800 Centerpoint Dr, Suite 1400 Anchorage, Alaska 99503 11/13/2025 Commissioners – Jessie Chmielowski, Greg Wilson Alaska Oil and Gas Conservation Commission 333 West 7th Avenue Anchorage, Alaska 99501 Subject: Response to OTH-25-006: Notice of Proposed Enforcement Action. Dear Commissioner Chmielowski and Commissioner Wilson, Hilcorp North Slope, LLC will not contest the proposed civil penalty stated in the 11/5/2025 Notice of Proposed Enforcement Action: Docket OTH-25-006, pertaining to the self-reported unauthorized injection of enriched hydrocarbon gas into the Polaris Oil Pool wells S-201A (PTD# 219092) and S-210 (PTD#219057). Hilcorp strives for continued reduction of non-compliance events with increased training, oversite and tools to assist in tracking of injection compliance activities with the ultimate goal of zero non-compliance events. Increased training and focus placed on injection compliance following previous incidents contributed to the discovery and immediate self-reporting of unauthorized injection into S-201A and S-210, dating back in part to the previous operator. Unauthorized injection on S-201A and S-210 has driven the Hilcorp North Slope team to implement additional substantive actions to prevent recurrence. If you have any questions, please contact me at 907-777-8445. Sincerely, Vanessa Hughes PBW Asset Team Lead By Samantha Coldiron at 8:55 am, Nov 14, 2025 Digitally signed by Vanessa Hughes (793) DN: cn=Vanessa Hughes (793) Date: 2025.11.13 13:30:27 - 09'00' Vanessa Hughes (793) 3 Alaska Oil and Gas Conservation Commission 333 West Seventh Avenue Anchorage, Alaska 99501-3572 Main: 907.279.1433 Fax: 907.276.7542 www.aogcc.alaska.gov November , 2025 CERTIFED MAIL – RETURN RECEIPT 7018 0680 0002 2052 9815 Mr. Wyatt Rivard Well IntegrityManager Hilcorp Alaska, LLC 3800 Centerpoint Drive, Suite 1400 Anchorage, AK 99503 Re:Notice of Proposed Enforcement Action Docket Number: OTH-25-006 Unauthorized Injection of Enriched Gas into Polaris Oil Pool in Prudhoe Bay Unit (PBU) Wells S-201A (PTD 2190920) and S-210 (PTD 2190570) Area Injection Order (AIO) 25A Prudhoe Bay Field, Polaris Oil Pool Dear Mr. Rivard; The Alaska Oil and Gas Conservation Commission (AOGCC) hereby notifies Hilcorp North Slope, LLC (Hilcorp) of a proposed enforcement action. Nature of the Apparent Violation or Noncompliance (20 AAC 25.535(b)(1)). PBU Well S-201A (PTD 2190920) and PBU Well S-210 (PTD 2190570): For wells S-201A and S-210, Hilcorp violated the provisions of Rule 2 (“Fluid Injection Wells”) of AIO 25A, which limited enriched gas injection in the Polaris Oil Pool to three wells (S-215i, W-208i, and W-215i) and provided procedures for obtaining enriched gas injection authority for additional wells. Basis for Finding the Violation or Noncompliance (20 AAC 25.535(b)(2)). Wells S-201A and S-210 were permitted to be drilled as water alternating gas (WAG) injectors in the Polaris pool and drilled/completed in late 2019/early 2020 by the previous operator. In addition to being permitted as WAG injectors, the wells would need a specific authorization under Rule 2 of AIO 25A before commencing enriched hydrocarbon gas injection. S-201A commenced enriched hydrocarbon gas injection in April 2020 under the previous operator, while S-210 began enriched hydrocarbon gas injection in October 2020 under Hilcorp operatorship. Both wells have undergone Notice of Proposed Enforcement Action Unauthorized Injection PBU S-201A and S-210 Docket Number: OTH-25-006 November , 2025 Page 2 of 4 numerous WAG cycles since 2020, with accurate injection types and volumes consistently reported to the AOGCC. On December 12, 2024, the AOGCC was notified by Hilcorp of enriched hydrocarbon gas injection into the Polaris pool without authorization per Rule 2 of AIO 25A. Hilcorp stated that “no record has been found of requested authorization required under Rule 2 of AIO 25A for enriched hydrocarbon gas injection for either well”. The facts reported by Hilcorp indicate a failure to operate these wells in compliance with the requirements specified in AIO 25A, Rule 2: “The underground injection of enriched gas for enhanced oil recovery is authorized only in the following wells: S-215i, W-209i, and W-215i. Upon proper application, the Commission may approve additional wells for injection of enriched gas within the Polaris Oil Pool.” On February 4, 2025, the AOGCC issued a Notice of Investigation (NOI) requesting details pertinent to the unauthorized injection of enriched hydrocarbon gas in both wells. AOGCC received Hilcorp’s response on March 6, 2025. Injection records, and Hilcorp’s response to the NOI, indicate Hilcorp violated Area Injection Order 25A, Rule 2 by injecting unauthorized enriched gas in S-201A for 759 days and in S-210 for 480 days. Similar Recent Violations. On February 6, 2024, the AOGCC issued Other Order 208, assessing Hilcorp with a civil penalty in the amount of $452,100 for the unauthorized injection violations on the L-109 and S-104 wells. For the L-109 and S-104 violations, Hilcorp completed an internal investigation (emailed to the AOGCC dated June 27, 2023 (L-109) and August 30, 2023 (S-104)) that included a root cause analysis and actions to prevent recurrence. Specifically, from Hilcorp’s investigation into the unauthorized injection into S-104, the following actions were taken to prevent recurrence: x The discovery of unauthorized injection into S-104 was due to work associated with reviewing all multi-zone completion wells. Hilcorp has finished this audit and found no additional errors. x Additional training with staff engineers completed on 8/22/2023. x Development and implementation of an injection well tracking resource to document authorized injection zones, injection fluids and commingled injection on an individual well basis in PBU. Implementation to be completed by 10/1/2023. Hilcorp’s actions to prevent reoccurrence, identified and implemented due to L-109 and S-104 violations, failed to identity and halt unauthorized injection in S-201A and S-210. Proposed Action (20 AAC 25.535(b)(3). The unauthorized injection violations are not isolated incidents but indicate an ongoing pattern of noncompliance by Hilcorp. Following the reviews and corrective actions related to the L-109 and S- Notice of Proposed Enforcement Action Unauthorized Injection PBU S-201A and S-210 Docket Number: OTH-25-006 November , 2025 Page 3 of 4 104 incidents, Hilcorp assured the AOGCC that it had implemented an injection well tracking system to document authorized injection zones, injection fluids, and commingled injection for each well in the PBU. However, the occurrence of two additional identical violations demonstrates that the corrective measures implemented in 2023 were ineffective. The recurrence of this issue raises serious concerns about Hilcorp’s ability to achieve and maintain regulatory compliance. For these violations, the AOGCC intends to impose civil penalties on Hilcorp as follows.1 S-201A Well: - $100,000 - Initial violation (S-201A) unauthorized injection into the Schrader Bluff-Orion Oil Pool in violation of AIO 25A Rule 2. - $303,600 for 759 days S-201A was operable/injecting enriched gas while unauthorized. S-210 Well: - $100,000 – Initial violation (S-210) unauthorized injection into the Schrader Bluff-Orion Oil Pool in violation of AIO 25A Rule 2. - $192,000 for 480 days S-210 was operable/injecting enriched gas while unauthorized. In addition to the imposed civil penalty, the AOGCC has historically required Hilcorp to provide a detailed written explanation as to how it intends to prevent recurrence of this violation. The AOGCC has also historically required Hilcorp to demonstrate to the AOGCC’s satisfaction a more robust regulatory compliance tracking system that addresses all AOGCC-mandated obligations. For these S- 201A and S-210 violations, as a result of a NOI issued to Hilcorp on February 4, 2025, by the AOGCC, Hilcorp completed an internal investigation that was included in its NOI response to the AOGCC dated March 5, 2025. This included a root cause analysis and corrective actions to prevent recurrence. Thus, the AOGCC will not require an additional written explanation from Hilcorp. The total proposed civil penalty is $695,600. Violations relating to Underground Injection Control Class II practices warrant the imposition of civil penalties. Evidence indicates that Hilcorp was clearly aware of the obligation established under AIO 25A, Rule 2, requiring specific authorization prior to the injection of enriched gas, as reflected in its prior submissions seeking such authorization for other wells before its self-report in December 2024 (see AIO 25A.020, AIO 25A.023, AIO 25A.024, and AIO 25A.025). Hilcorp’s repeated failure to comply with fundamental injection authorization raises the potential for similar behavior with more serious consequences. Hilcorp’s repeated failure to comply with AOGCC rules and regulations combined with ineffective corrective actions, warrant increased civil penalties to deter similar behavior. The factors in AS 31.05.150(g) were considered in determining the appropriate penalty. Mitigating circumstances include the existing PBU Western Operating Area aquifer exemption, no injury to the public or the environment, and Hilcorp’s notification to the AOGCC once Hilcorp determined the well(s) non-compliance(s). 1 AS 31.05.150(a) provides for not more than $100,000 for the initial violation and not more than $10,000 for each day thereafter on which the violation continues. Notice of Proposed Enforcement Action Unauthorized Injection PBU S-201A and S-210 Docket Number: OTH-25-006 November , 2025 Page 4 of 4 Rights and Liabilities (20 AAC 25.535(b)(4)). Within 15 days after receipt of this notification – unless the AOGCC, in its discretion, grants an extension for good cause shown – Hilcorp may file with the AOGCC a written response that concurs in whole or in part with the proposed action described herein, requests informal review, or requests a hearing under 20 AAC 25.540. If a timely response is not filed, the proposed action will be deemed accepted by default. If informal review is requested, the AOGCC will provide Hilcorp an opportunity to submit documentary material and make a written or oral statement. If Hilcorp disagrees with the AOGCC’s proposed decision or order after that review, it may file a written request for a hearing within 10 days after the proposed decision or order is issued. If such a request is not filed within that 10-day period, the proposed decision or order will become final on the 11th day after it was issued. If such a request is timely filed, the AOGCC will hold its decision in abeyance and schedule a hearing. If Hilcorp does not concur in the proposed action described herein, and the AOGCC finds that Hilcorp violated a provision of AS 31.05, 20 AAC 25, or an AOGCC order, permit or other approval, then the AOGCC may take any action authorized by the applicable law including ordering one or more of the following: (i) corrective action; (ii) suspension or revocation of a permit or other approval; and (iii) imposition of penalties under AS 31.05.150. In taking action after an informal review or hearing, the AOGCC is not limited to ordering the proposed action described herein, as long as Hilcorp received reasonable notice and opportunity to be heard with respect to the AOGCC’s action. Any action described herein or taken after an informal review or hearing does not limit the action the AOGCC may take under AS 31.05.160. Sincerely, Jessie L. Chmielowski Gregory C. Wilson Commissioner Commissioner cc: Timothy Mayers, (mayers.timothy@epa.gov) EPA, Region 10 Jim Regg, AOGCC Supervisor, Inspections AOGCC Inspectors Dave Roby, AOGCC Sr. Reservoir Engineer Jack Lau, AOGCC Sr. Petroleum Engineer Jessie L. Chmielowski Digitally signed by Jessie L. Chmielowski Date: 2025.11.04 13:53:47 -09'00' Gregory C Wilson Digitally signed by Gregory C Wilson Date: 2025.11.05 07:59:04 -09'00' 2 Hilcorp North Slope, LLC Kyle Koerber, PBE Asset Team Leader 3800 Centerpoint Dr, Suite 1400 Anchorage, Alaska 99503 03/05/2025 Commissioners – Jesse Chmielowski, Greg Wilson Alaska Oil and Gas Conservation Commission 333 West 7th Avenue Anchorage, Alaska 99501 Subject: Hilcorp North Slope, LLC response to OTH-25-006 Request for Information, Notice of Investigation regarding self- report of injection of unauthorized fluid into PBU Polaris S-201A (PTD #219-092) and S-210 (PTD #219-057) Dear Commissioner Chmielowski and Commissioner Wilson, Please see below for AOGCC requested information compiled regarding the self-reported discovery of unauthorized injection of miscible injectant (MI) into PBU Polaris S-201A (PTD #219-092) between 04/18/2020 – 12/10/2024 and PBU Polaris S-210 (PTD #219-057) between 10/10/2020 – 09/25/2024. AOGCC Information Request: 1. The number of days S-201A and S-210 were on enriched gas injection without AOGCC authorization; 2. The total volume of enriched gas injected into S-201A and S-210 without AOGCC authorization; See Documents:“S-201A Injection Volumes_2020-2024”and “S-210 Injection Volumes_2020-2024” S-201A was sidetracked from the parent bore in January 2019 and permitted as a Water Alternating Gas (WAG) injector. The well was officially completed in April 2020 and subsequently placed on MI service 04/18/2020 under the previous operator. A total of 5 MI slugs were injected into the well between 04/18/2020 and 12/10/2024. This totaled 759 days and 2,103,267 MSCFD of MI injection. S-210 was drilled as a grass root well in December 2019 and permitted as a WAG injector. The well was officially completed in April 2020 and subsequently placed on produced water (PW) injection 04/14/2020. The first slug of MI was injected into the well starting 10/10/2020 under Hilcorp operatorship. A total of 5 MI slugs were injected into the well between 10/10/2020 and 9/25/2024.This totaled 480 days and 1,255,129 MSCFD of MI injection. 3. 12 month TIO raw data (excel format) and pressure plot identifying TIO pressures, injection rate, injection temperatures, and any bleed events of S-201A and S-210; See Document:“S-201A S-210 12-month TIO and Injection Data” 4. Full root cause analysis, including results and conclusions, addressing the failure and corrective actions to avoid recurrence; See Document:“Timeline of Events S-201 S-210 Misinjection Investigation” Root cause of the incident: Transfer of operatorship: x Individuals making decisions were unaware of Polaris Oil Pool specific AIO requirements. Inadequate work process: By Samantha Coldiron at 7:50 am, Mar 06, 2025 x Injection Computer Based Training exists but was not assigned correctly in 2020 and is not specific to Polaris Oil Pool AIO. x No process in place for RE and OE verification of AIO requirements. Contributing factors of the incident: x RE and OE review of Polaris injectors in July 2023 failed to recognize that existing AA’s for S-201A and S-210 were due to well completions and not for authorization of MI. Same lack of awareness impacted review process by not recognizing hazards present with pool specific AIO requirements. Actions to prevent recurrence: x Request an update to AIO 25A to modify Rule 2. x Create AIO & CO Pool summary, controlled documentation. Maintain 6-month review and approval by Land and Asset Team Leader. Document used for training of new engineers. 5. Results of a review of each of the Hilcorp injectors authorized by AIO 25A (which includes any issued administrative approvals) specifically to the authorization of approved fluids and WAG status, and identification of any wells that are out of compliance; and See Document: “Polaris Injector Compliance Review” There were no AIO 25A anomalies found from this review. 6. Any supplementary information, including relevant data and correspondence, that Hilcorp wishes to submit on their behalf. See e-mail: “[EXTERNAL] RE: PBU M-207 PTD #224-141 Clarifications” Communication to the AOGCC was sent on 12/9/2024 for PBU Polaris M-207 (PTD #224-141), to request clarification of “proper application” for injecting enriched hydrocarbon gas per AIO 25A Rule 2 based on questions pertaining to PTD approval of WAG service. Clarification response from the AOGCC staff prescribed AIO administrative approval process as the form of proper application. Based on the response from the AOGCC, an additional review of Polaris injector wells was initiated. Through review, unauthorized MI injection into S-201A and S-210 was discovered. Subsequently, Hilcorp self-reported these issues to AOGCC 12/12/2024. This second review of Polaris injectors uncovered the lack of RE and OE awareness which impacted the initial review process (S-104 investigation 8/2023) in determining approval for MI injection. S-201A and S-210 each have approved AA’s for continued WAG injection with a “cement packer”. In the initial Polaris injector review, these AA’s (AIO 25A.021 and AIO 25A.022) were misinterpreted as approvals for MI injection. See Documents: “AOR for S-201Ai_Original 2019”, “AOR for S-201Ai_Updated 2025”, “AOR for S-210_Original 2019”, “AOR for S-210_Updated 2025” Upon review of S-201A and S-210, in preparation for submission of Administrative Approval requests to allow for MI service, it was determined that offset wellbore isolation within one-quarter mile of both S-201A and S-210 were not compliant with 20 AAC 25.030.d.5, “intermediate and production casing must be cemented with sufficient cement to fill the annular space from the casing shoe to a minimum of 500 feet measured depth or 250 feet true vertical depth, whichever is greater, above all significant hydrocarbon zones...”. x S-201A AOR: The original AOR for S-201A included in the 2019 permit to drill reported that parent well S-201 (PTD #200-184) had a top of cement (TOC) 284’ TVD (316’ MD) above the top of Polaris Oil Pool, logged with a USIT. A review of the S-201 cement bond log shows TOC is only 188’ TVD (206’ MD) above top of pool. x S-210 AOR: The original AOR for S-210 included six offset wellbores in a one-quarter mile radius. Upon review of the AOR, it was discovered that three additional offset wellbores were left out, PBU S-21 (PTD #190-047), PBU S-23 (PTD #190-127), and PBU S-24A (PTD #198-245). Well S-23 was found to only have 162’ TVD (257’ MD) of cement coverage above the top of Polaris Oil Pool, calculated volumetrically. Well S-24A was found to have no cement coverage across or above the Polaris pool. As a result of the AOR reviews, S-201A and S-210 were shut-in 2/20/2025. Confinement waterflow logging was initially completed on S-201A and S-210 in 4/2021, which confirmed containment of water injection to the Polaris pool. Hilcorp does not believe that these incidents have promoted waste, jeopardized ultimate recovery of hydrocarbons from the Polaris Oil Pool nor have these incidents increased risk to health, safety or the environment. Hilcorp is evaluating justifications to support AA requests for continued operation of the subject wells. With the creation of a centralized Hilcorp Alaska Well Integrity team and an increased focus on regulatory compliance activities, the discovery of these ongoing unauthorized injection events reflects the improved oversite of critical compliance activities noted in the recent Hilcorp Alaska and Hilcorp North Slope regulatory compliance gap assessment. If you have any questions, please call me at 907-564-4887 or Oliver Sternicki at 907-564-4891. Sincerely, Kyle Koerber PBE Asset Team Leader noted in the recent Hilcorp Alaska a If you have any questions, please ca Sincerely, Kyle Koerber PBE Asset Team Leader CAUTION: This email originated from outside the State of Alaska mail system. Do not click links or open attachments unless you recognize the sender and know the content is safe. CAUTION: External sender. DO NOT open links or attachments from UNKNOWN senders. From:Wallace, Chris D (OGC) To:Tyson Shriver Cc:Rixse, Melvin G (OGC); Lau, Jack J (OGC); Roby, David S (OGC) Subject:[EXTERNAL] RE: PBU M-207 PTD #224-141 Clarifications Date:Monday, December 9, 2024 6:44:51 PM Tyson, AOGCC approves the variance request to not perform the step rate test or surveillance log (AIO 25A Rule 4 requirement) for this well. Instead, the well will be limited to the 0.8 psi/ft injection pressure. Looking at AIO 25A, wells have individually been approved for enriched hydrocarbon gas (Rich Gas) via the AIO administrative approval process. You can utilize the same process, and provide the same information, as AIO 25A.025 for S-104 (PTD 2001960) which looks like the most recently issued. Information to support the AIO and regulation requirements for confirming/passing zonal isolation and well integrity etc for M-207 should be included with the AA request as this information will not have been previously provided to the commission due to the new drill. Hilcorp could evaluate how many additional wells are in this situation, and determine if an update to the 20 year old AIO 25A would be more efficient than doing this well by well. Thanks and Regards, Chris Wallace, Sr. Petroleum Engineer, Alaska Oil and Gas Conservation Commission, 333 West 7th Avenue, Anchorage, AK 99501, (907) 793-1250 (phone), (907) 276-7542 (fax), chris.wallace@alaska.gov CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, contains information from the Alaska Oil and Gas Conservation Commission (AOGCC), State of Alaska and is for the sole use of the intended recipient(s). It may contain confidential and/or privileged information. The unauthorized review, use or disclosure of such information may violate state or federal law. If you are an unintended recipient of this e-mail, please delete it, without first saving or forwarding it, and, so that the AOGCC is aware of the mistake in sending it to you, contact Chris Wallace at 907-793-1250 or chris.wallace@alaska.gov. From: Tyson Shriver <Tyson.Shriver@hilcorp.com> Sent: Monday, December 9, 2024 3:56 PM To: Wallace, Chris D (OGC) <chris.wallace@alaska.gov> Cc: Rixse, Melvin G (OGC) <melvin.rixse@alaska.gov>; Lau, Jack J (OGC) <jack.lau@alaska.gov> Subject: PBU M-207 PTD #224-141 Clarifications Mr. Wallace, I am looking for a couple clarifications on the approved PBU M-207 PTD (#224-141). The approved PTD is attached for quick reference. M-207 was permitted as a WAG injector in the Polaris Oil Pool. Per Rule 2 of AIO 25A “The underground injection of enriched gas for enhanced oil recovery is authorized only in the follow wells: S-215i, W-209i, and W-215i. Upon proper application, the Commission may approve additional wells for injection of enriched gas within the Polaris Oil Pool.” Please let me know if the PTD for M-207 is a proper application or a separate Administrative Approval is needed for enriched hydrocarbon gas injection. A variance was requested to AIO 25A Rule 4 to not perform a step rate test or surveillance log within three months of start of injection (page #8 of the drilling program). I do not see any comments approving or denying the variance request in the approved PTD. Could you please confirm if Hilcorp’s variance request to AIO 25A Rule 4 is approved? Thank you, Tyson Shriver Hilcorp Alaska PBW GC2 OE (L, V, W, Z) o: 907-564-4542 c: 406-690-6385 The information contained in this email message is confidential and may be legally privileged and is intended only for the use of theindividual or entity named above. If you are not an intended recipient or if you have received this message in error, you are herebynotified that any dissemination, distribution, or copy of this email is strictly prohibited. If you have received this email in error, pleaseimmediately notify us by return email or telephone if the sender's phone number is listed above, then promptly and permanently deletethis message. While all reasonable care has been taken to avoid the transmission of viruses, it is the responsibility of the recipient to ensure that the onward transmission, opening, or use of this message and any attachments will not adversely affect its systems or data. No responsibility is accepted by the company in this regard and the recipient should carry out such virus and other checks as it considers appropriate. Well Name PTD API Distance / Status Top of Oil Pool (SB Na, MD) Top of Oil Pool (SB Na, TVDss) Top of Cmt (MD) Top of Cmt (TVDss) Zonal Isolation Comments PBU S-201A 219-092 50-029-22987-01-00 0' / Injector 6494'4883'5170'3862'Closed Pumped 67 bbls 15.0 ppg Acid Soluble cement. Losses encountered when cement exit shoe. 3-1/2" TOC logged at 5,170' with RCBL 2/25/2020. Patch in tubing from 4,923' to 4,955' MD set 4/17/2024. Passing MIT-IA to 3,675 psi 4/24/2024. PBU S-201 200-184 50-029-22987-00-00 438' / Abandoned 6516'4870'6310'4682'Open Pumped 45 bbls 11.5ppg LiteCrete followed by 75 bbls 15.8 ppg Class 'G' cement. A total of 55 bbls of cement was lost during the cement job. 7" TOC logged at 6,310' with USIT on 12/7/2005. Well was then P&A'd for sidetrack in 2019. TOC in 3-1/2" tubing at 6,150' MD. TOC in 3-1/2" x 7" aunnulus at 5,894' MD. Not open to Schrader Bluff. PBU S-103 200-168 50-029-22981-00-00 985' / Producer 6629'4860'3888'3243'Closed Pumped 161 bbls 11.5 LiteCrete followed by 57 bbls 15.8 ppg Class 'G' cement. 100% returns achieved throughout job. Including shoe track volume, volumetric calculations place the TOC in the 7" x 8.75" OH annulus at ~3,888' MD when accounting for 30% washout. Not open to Schrader Bluff. Passing CMIT TxIA to 3,450 psi 10/3/2005. Passing TIFL 11/28/2017. PBU S-105 200-152 50-029-22977-00-00 1178' / Producer 5610'4939'3313'3031'Closed Pumped 115 bbls 11.5 LiteCrete followed by 55 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 7" x 8.75" OH annulus at ~3,313' MD when accounting for 30% washout. Well was CTD sidetracked to S-105A (PTD #219-032) but utilizes parent well S-105's production casing. Not open to the Schrader Bluff. Passing MIT-IA to 3,654 psi 10/4/2019. Passing TIFL 8/23/2024. PBU S-121 206-041 50-02923304-00-00 1315' / Producer 6595'4961'4544'3562'Closed Two stage cement job. Stage 1 pumped 37 bbls 12.5 ppg LiteCrete followed by 43.4 bbls 15.8 ppg Class 'G' cement. Opened ES cemented at 7820' and circulated out 70 bbls cement contaminated mud. Stage 2 pumped 73.6 bbls 12.5 ppg LiteCrete followed by 40.6 ppg Class 'G' cement. No losses reported. Volumetric calculations place TOC in 7" x 8.75" OH annulus at 4544' MD when accounting for 30% washout. Not open to Schrader Bluff. Passing MIT-IA to 2,441 psi 2/23/2014. Passing TIFL 7/27/2017. PBU S-122 205-081 50-029-23265-00-00 956' / Injector 6971'4895'4135'3331'Closed Pumped 175 bbls 11.0 ppg LiteCrete followed by 57 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 7" x 8.75" OH annulus at 4135' MD when accounting for 30% washout. Not open to Schrader Bluff. Passing MIT-IA to 3,426 psi 11/2/2024. Area of Review PBU S-201A S-103 S-201 S-201A S-122 S-105 S-121 5,982,000FT5,982,000FT5,984,000FT5,984,000FT5,986,000FT616,000 FT 616,000 FT 620,000 FT HILCORP NORT H SLOPE Greater Prudhoe Bay S-201A AOR Plot FEET 0 250 500 750 POSTED W ELL DATA Well Label W ELL SYMBOLS INJ Well (Water Flood) P&A Oil/Gas Active Oil By: JCS- 12/11/2024 December 16, 2024 PETRA 12/16/2024 1:25:57 PM S‐21005001,0001,5002,0002,5003,0003,500‐1009001,9002,9003,9004,9005,9002/28/20243/6/20243/13/20243/20/20243/27/20244/3/20244/10/20244/17/20244/24/20245/1/20245/8/20245/15/20245/22/20245/29/20246/5/20246/12/20246/19/20246/26/20247/3/20247/10/20247/17/20247/24/20247/31/20248/7/20248/14/20248/21/20248/28/20249/4/20249/11/20249/18/20249/25/202410/2/202410/9/202410/16/202410/23/202410/30/202411/6/202411/13/202411/20/202411/27/202412/4/202412/11/202412/18/202412/25/20241/1/20251/8/20251/15/20251/22/20251/29/20252/5/20252/12/20252/19/20252/26/2025BWPD / MCFPDPSITbg. PressureIAOAOOAOOOABleedsProd. VolumeInj. Volume S‐20105001,0001,5002,0002,5003,0003,5004,000‐1009001,9002,9003,9004,9005,9002/28/20243/6/20243/13/20243/20/20243/27/20244/3/20244/10/20244/17/20244/24/20245/1/20245/8/20245/15/20245/22/20245/29/20246/5/20246/12/20246/19/20246/26/20247/3/20247/10/20247/17/20247/24/20247/31/20248/7/20248/14/20248/21/20248/28/20249/4/20249/11/20249/18/20249/25/202410/2/202410/9/202410/16/202410/23/202410/30/202411/6/202411/13/202411/20/202411/27/202412/4/202412/11/202412/18/202412/25/20241/1/20251/8/20251/15/20251/22/20251/29/20252/5/20252/12/20252/19/20252/26/2025BWPD / MCFPDPSITbg. PressureIAOAOOAOOOABleedsProd. VolumeInj. Volume SWName ReportDateBegin ReportDateEnd ProductCode SubProductCode FlowCode InjectionVolumeAllocation HoursOperating DaysOperating WellheadPressureAverage WellheadPressureMaximum CasingPressureAverage CasingPressureMaximum PoolCode FacilityCode WellStatusS‐201A 4/1/2020 4/30/2020 GAS MI NONE 38,458.00 291.00 13.00 2,809.10 2,943.00 423.50 975.00 640160 GC‐2M9S‐201A 5/1/2020 5/31/2020 GAS MI NONE 83,811.00 744.00 31.00 2,823.20 2,908.00 787.90 1,000.00 640160 GC‐2M9S‐201A 6/1/2020 6/30/2020 GAS MI NONE 79,678.00 720.00 30.00 2,791.20 2,881.00 775.00 1,350.00 640160 GC‐2M9S‐201A 7/1/2020 7/31/2020 GAS MI NONE 81,259.00 744.00 31.00 2,798.10 2,866.00 729.80 1,050.00 640160 GC‐2M9S‐201A 8/1/2020 8/31/2020 GAS MI NONE 82,380.00 744.00 31.00 2,853.30 2,932.00 741.10 1,100.00 640160 GC‐2M9S‐201A 9/1/2020 9/30/2020 GAS MI NONE 80,508.00 720.00 30.00 2,876.80 2,960.00 559.20 1,250.00 640160 GC‐2M9S‐201A 10/1/2020 10/31/2020 GAS MI NONE 22,184.00 216.00 9.00 2,826.10 2,908.00 211.10 300.00 640160 GC‐2M9S‐201A 6/1/2021 6/30/2021 GAS MI NONE 11,186.00 140.46 6.00 2,676.90 2,745.00 0.00 0.00 640160 GC‐2M9S‐201A 7/1/2021 7/31/2021 GAS MI NONE 63,527.00 744.00 31.00 2,736.70 2,831.00 0.00 0.00 640160 GC‐2M9S‐201A 8/1/2021 8/31/2021 GAS MI NONE 36,419.00 338.89 15.00 2,738.50 3,015.00 0.00 0.00 640160 GC‐2M9S‐201A 9/1/2021 9/30/2021 GAS MI NONE 98,800.00 720.00 30.00 2,920.10 2,996.00 0.00 0.00 640160 GC‐2M9S‐201A 10/1/2021 10/31/2021 GAS MI NONE 96,315.00 744.00 31.00 2,898.00 2,961.00 0.00 0.00 640160 GC‐2M9S‐201A 11/1/2021 11/30/2021 GAS MI NONE 84,330.00 712.88 30.00 2,824.30 3,045.00 0.00 0.00 640160 GC‐2M9S‐201A 12/1/2021 12/31/2021 GAS MI NONE 6,359.00 73.64 4.00 2,341.60 2,815.00 53.40 200.00 640160 GC‐2M9S‐201A 6/1/2022 6/30/2022 GAS MI NONE 22,057.00 253.42 11.00 2,572.80 2,687.00 0.00 0.00 640160 GC‐2M9S‐201A 7/1/2022 7/31/2022 GAS MI NONE 79,944.00 744.00 31.00 2,799.30 2,950.00 0.00 0.00 640160 GC‐2M9S‐201A 8/1/2022 8/31/2022 GAS MI NONE 90,083.00 744.00 31.00 2,804.50 2,924.00 16.10 100.00 640160 GC‐2M9S‐201A 9/1/2022 9/30/2022 GAS MI NONE 93,133.00 696.00 29.00 2,844.70 3,030.00 5.20 150.00 640160 GC‐2M9S‐201A 10/1/2022 10/31/2022 GAS MI NONE 76,355.00 558.76 24.00 2,859.60 2,935.00 12.90 150.00 640160 GC‐2M9S‐201A 11/1/2022 11/30/2022 GAS MI NONE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 640160 GC‐2M8S‐201A 12/1/2022 12/31/2022 GAS MI NONE 56,729.00 422.66 18.00 2,317.10 2,490.00 2.80 50.00 640160 GC‐2M9S‐201A 1/1/2023 1/31/2023 GAS MI NONE 28,163.00 210.53 9.00 2,462.40 2,521.00 5.70 50.00 640160 GC‐2M9S‐201A 7/1/2023 7/31/2023 GAS MI NONE 4,924.00 53.78 3.00 2,773.70 2,883.00 0.00 0.00 640160 GC‐2M9S‐201A 8/1/2023 8/31/2023 GAS MI NONE 56,768.00 615.14 27.00 2,791.90 2,972.00 0.00 0.00 640160 GC‐2M9S‐201A 9/1/2023 9/30/2023 GAS MI NONE 64,166.00 504.81 22.00 2,725.00 2,822.00 0.00 0.00 640160 GC‐2M9S‐201A 10/1/2023 10/31/2023 GAS MI NONE 103,445.00 744.00 31.00 2,806.40 2,867.00 0.00 0.00 640160 GC‐2M9S‐201A 11/1/2023 11/30/2023 GAS MI NONE 92,997.00 720.00 30.00 2,715.00 2,879.00 0.00 0.00 640160 GC‐2M9S‐201A 12/1/2023 12/31/2023 GAS MI NONE 77,946.00 719.87 31.00 2,232.50 2,814.00 756.00 1,750.00 640160 GC‐2M9S‐201A 1/1/2024 1/31/2024 GAS MI NONE 10,829.00 82.32 4.00 2,406.70 2,807.00 568.50 700.00 640160 GC‐2M9S‐201A 2/1/2024 2/29/2024 GAS MI NONE 4,784.00 77.22 4.00 1,722.80 2,433.00 649.00 1,325.00 640160 GC‐2M9S‐201A 3/1/2024 3/31/2024 GAS MI NONE 64,152.00 686.75 29.00 2,135.80 2,650.00 1,133.60 1,850.00 640160 GC‐2M9S‐201A 4/1/2024 4/30/2024 GAS MI NONE 62,032.00 475.95 21.00 2,542.60 2,679.00 664.30 1,650.00 640160 GC‐2M9S‐201A 5/1/2024 5/31/2024 GAS MI NONE 98,227.00 744.00 31.00 2,542.60 2,607.00 547.60 700.00 640160 GC‐2M9S‐201A 6/1/2024 6/30/2024 GAS MI NONE 62,665.00 464.37 21.00 2,554.40 2,946.00 630.10 850.00 640160 GC‐2M9S‐201A 9/1/2024 9/30/2024 GAS MI NONE 1,240.00 16.04 2.00 2,413.60 2,924.00 537.60 550.00 640160 GC‐2M9S‐201A 10/1/2024 10/31/2024 GAS MI NONE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 640160 GC‐2M8S‐201A 11/1/2024 11/30/2024 GAS MI NONE 55,739.00 424.88 18.00 2,928.90 3,029.00 689.20 750.00 640160 GC‐2M9S‐201A 12/1/2024 12/31/2024 GAS MI NONE 31,675.00 231.37 10.00 3,038.00 3,127.00 713.70 750.00 640160 GC‐2M9 Well Name PTD API Distance / Status Top of Oil Pool (SB Na, MD) Top of Oil Pool (SB Na, TVDss) Top of Cmt (MD) Top of Cmt (TVDss) Zonal Isolation Comments PBU S-210 219-057 50-029-23630-00-00 0' / Injector 6494'4883'2328'2236'Closed Pumped 215 bbls 13.0 ppg LiteCrete followed by 80 bbls 15.0 ppg Class 'G' Acid Soluble cement. No losses reported. 3- 1/2" TOC logged at 2,328' with SCMT 1/10/2020. Passing MIT-IA to 3,522 psi 1/27/2024. PBU S-03 181-190 50-029-20695-00-00 1219' / Producer 5940'4861'2040'1968'Closed Primary job pumped 153 bbls 15.8 ppg Class 'G' cement. No losses reported. The 9-5/8" x 13-3/8" annulus was downsqueezed with 50 bbls of ArcticSet I followed by 120 bbls Arctic Pack. 9-5/8" TOC logged at 2,040' with USIT 12/20/2005. Not open to Schrader Bluff. Passing TIFL 9/16/2024 PBU S-105 200-152 50-029-22977-00-00 1341' / Producer 5610'4939'3313'3031'Closed Pumped 115 bbls 11.5 ppg LiteCrete followed by 55 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 7" x 8.75" OH annulus at ~3,313' MD when accounting for 30% washout. Well was CTD sidetracked to S-105A (PTD #219-032) but utilizes parent well S-105's production casing. Not open to the Schrader Bluff. Passing MIT-IA to 3,654 psi 10/4/2019. Passing TIFL 8/23/2024. PBU S-108 201-100 50-029-23021-00-00 1194' / Abandoned 5587'4916'3196'3122'Closed Pumped 87 bbls 12.0 ppg LiteCrete followed by 57 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 3-1/2" / 5-1/2" x 6.75" OH at ~3,196' MD when accounting for 30% washout. Well was P&A'd in to surface in 2014. PBU S-200 197-239 50-029-22846-00-00 1010' / Abandoned 5719'4840'4327'3745'Closed 7" intermediate casing was run to 4,476' MD (3,860' TVDss) and cemented with 48 bbls 15.8 ppg Class 'G' cement. No losses reported. Volumetric calculations place the TOC of the 7" casing inside the 9-5/8" shoe when accoutning for 30% washout. Injection was established post cementing down the 7" x 9-5/8" annulus for freeze protect. 3.5" liner was run to 6,310' MD and cemented with 69 bbls 15.8 Class 'G' cement. No losses reported. Volumetric calculations place the TOC of the 3.5" x 6" OH at the top of liner at 4,327' MD when accounting for 30% washout. Well was P&A'd for sidetrack in 2017. PBU S-200PB1 197-239 50-029-22846-70-00 754' / Abandoned 5603'4861'4488'3869'Closed An 8-1/2" intermediate hole was drilled from the 9-5/8" surface casing shoe at 3,159' MD (3,015' TVDss) to a total depth of 6,150' MD (5,407' TVDss). The hole was abandoned in two stages; first stage circulated in an 83 bbl 15.8 ppg Class 'G' cement plug from 6,150' MD, second stage circulated in an 83 bbl 15.8 ppg Class 'G' cement plug from 5,289' MD. Cement was then drilled out to 4,488' MD. PBU S-21 190-047 50-029-22036-00-00 767' / Producer 5224'4876'4902'4622'Closed Pumped 267 bbls 13.5ppg 13.5 Class 'G' followed by 102 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 9.875" x 12.25" OH annulus at ~4,902' MD when accounting for 30% washout. 9-5/8" x 13-3/8" annulus downsqueezed with cement in 2002. Not open to Schrader Bluff. Failed CMIT-TxIA 11/1/2023. LLR 0.56 gpm @ 2300 psi. Packer or PC leak. PBU S-23 190-127 50-029-22088-00-00 1155' / Producer 5430'4880'5173'4718'Open Pumped 324 bbls 13.5ppg 13.5 Class 'G' followed by 102 bbls 15.8 ppg Class 'G' cement. No losses reported. Including shoe track volume, volumetric calculations place the TOC in the 9.875" x 12.25" OH annulus at ~5,173' MD when accounting for 30% washout. 9-5/8" x 13-3/8" annulus downsqueezed with cement in 2003. Not open to Schrader Bluff. Passing CMIT-TxIA to 2,600 psi 11/21/2024. PBU S-24A 198-245 50-029-22044-01-00 775' / Producer 5499'4873'6349'5511'Open Pumped 195 bbls 11.5ppg Class 'G' followed by 55 bbls 15.8 ppg Class 'G' cement. 12 bbls of losses reported. Including shoe track volume and losses, volumetric calculations place the TOC in the 7" x 9.875" OH annulus at ~6349' MD when accounting for 30% washout. S-24A has had a deep CTD sidetrack and is now S-24B but still uses the previous S-24A Production Casing. Open to Schrader Bluff. Failed CMIT-TxIA 7/22/2024. Packer or PC leak. PBU S-31 190-159 50-029-22109-00-00 767' / Injector 5646'4880'5250'4591'Closed Pumped 376 bbls 13.5ppg 13.5 Class 'G' followed by 41 bbls 15.8 ppg Class 'G' cement. No losses reported. 9-5/8" TOC logged at 5,250' with USIT 11/27/2006. Well was CTD sidetracked in the Ivishak reservoir November 1998 and subsequently recompleted to the Kuparuk reservoir in a 2006 workover. S-31'A' still uses the parent S-31 9-5/8" casing. Not open to Schrader Bluff. Passing MIT-IA to 2,607 psi 2/4/2023. Area of Review PBU S-210 -Injection Interval SWName ReportDateBegin ReportDateEnd ProductCode SubProductCode FlowCode InjectionVolumeAllocation HoursOperating DaysOperating WellheadPressureAverage WellheadPressureMaximum CasingPressureAverage CasingPressureMaximum PoolCode FacilityCode WellStatusS‐210 10/1/2020 10/31/2020 GAS MI NONE 40,395.00 464.59 20.00 2,973.60 3,032.00 0.00 0.00 640160 GC‐2M9S‐210 11/1/2020 11/30/2020 GAS MI NONE 55,015.00 621.45 26.00 3,019.10 3,107.00 0.00 0.00 640160 GC‐2M9S‐210 12/1/2020 12/31/2020 GAS MI NONE 64,195.00 744.00 31.00 2,986.30 3,118.00 0.00 0.00 640160 GC‐2M9S‐210 1/1/2021 1/31/2021 GAS MI NONE 67,701.00 744.00 31.00 2,938.90 3,010.00 0.00 0.00 640160 GC‐2M9S‐210 2/1/2021 2/28/2021 GAS MI NONE 72,315.00 672.00 28.00 2,990.60 3,072.00 0.00 0.00 640160 GC‐2M9S‐210 3/1/2021 3/31/2021 GAS MI NONE 17,722.00 161.39 7.00 3,027.10 3,069.00 0.00 0.00 640160 GC‐2M9S‐210 2/1/2022 2/28/2022 GAS MI NONE 55,935.00 660.97 28.00 2,490.20 2,700.00 363.10 850.00 640160 GC‐2M9S‐210 3/1/2022 3/31/2022 GAS MI NONE 39,966.00 336.00 14.00 2,690.50 2,741.00 696.40 1,050.00 640160 GC‐2M9S‐210 4/1/2022 4/30/2022 GAS MI NONE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 640160 GC‐2M8S‐210 5/1/2022 5/31/2022 GAS MI NONE 14,173.00 221.98 10.00 1,997.90 2,702.00 54.10 200.00 640160 GC‐2M9S‐210 6/1/2022 6/30/2022 GAS MI NONE 10,253.00 160.74 8.00 2,023.50 2,755.00 141.80 250.00 640160 GC‐2M9S‐210 7/1/2022 7/31/2022 GAS MI NONE 101.00 1.42 1.00 1,361.00 1,361.00 0.00 0.00 640160 GC‐2M9S‐210 1/1/2023 1/31/2023 GAS MI NONE 28,607.00 221.01 10.00 2,661.60 2,717.00 2.30 100.00 640160 GC‐2M9S‐210 2/1/2023 2/28/2023 GAS MI NONE 82,677.00 588.35 25.00 2,657.80 2,949.00 0.00 0.00 640160 GC‐2M9S‐210 3/1/2023 3/31/2023 GAS MI NONE 68,985.00 627.72 27.00 2,353.50 2,453.00 0.00 0.00 640160 GC‐2M9S‐210 4/1/2023 4/30/2023 GAS MI NONE 100,720.00 714.64 30.00 2,472.20 2,663.00 0.00 0.00 640160 GC‐2M9S‐210 5/1/2023 5/31/2023 GAS MI NONE 105,250.00 744.00 31.00 2,483.50 2,523.00 0.00 0.00 640160 GC‐2M9S‐210 6/1/2023 6/30/2023 GAS MI NONE 97,403.00 720.00 30.00 2,432.30 2,536.00 0.00 0.00 640160 GC‐2M9S‐210 7/1/2023 7/31/2023 GAS MI NONE 51,788.00 528.00 22.00 2,259.70 2,444.00 0.00 0.00 640160 GC‐2M9S‐210 1/1/2024 1/31/2024 GAS MI NONE 39,082.00 270.90 12.00 2,660.20 2,843.00 119.60 400.00 640160 GC‐2M9S‐210 2/1/2024 2/29/2024 GAS MI NONE 91,697.00 696.00 29.00 2,530.90 2,617.00 74.10 400.00 640160 GC‐2M9S‐210 3/1/2024 3/31/2024 GAS MI NONE 48,566.00 520.47 22.00 2,179.80 2,298.00 59.90 150.00 640160 GC‐2M9S‐210 8/1/2024 8/31/2024 GAS MI NONE 32,110.00 293.74 13.00 2,483.30 2,656.00 0.00 0.00 640160 GC‐2M9S‐210 9/1/2024 9/30/2024 GAS MI NONE 70,473.00 588.08 25.00 2,430.60 2,762.00 2.00 50.00 640160 GC‐2M9S‐210 10/1/2024 10/31/2024 GAS MI NONE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 640160 GC‐2M8S‐210 11/1/2024 11/30/2024 GAS MI NONE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 640160 GC‐2M8 Well AOGCC Current Status Hilcorp AKIMS Well Type AIO 25A AA for MI (Y/N)AA Number Date of AA In Compliance (Y/N)Comments S-104 Water alt gas injection Water Alternating Gas Y AIO 25A.025 7/23/2024 Y M-201 Water alt gas injection Water Alternating Gas Y AIO 25A.024 7/23/2024 Y M-205 Water alt gas injection Water Alternating Gas Y AIO 25A.023 7/23/2024 Y M-207 Water alt gas injection Water Alternating Gas N --Y New drill AIO 25A compliance risk. Has only been on PW service. AA request for MI injection submitted on 2/14/2025 to AOGCC S-201A Water alt gas injection Water Alternating Gas N --N MI injection without approved AA per AIO 25A S-210 Water alt gas injection Water Alternating Gas N --N MI injection without approved AA per AIO 25A S-215 Water alt gas injection Water Alternating Gas ---Y Approved under original issue of AIO 25A.000 S-216 Water alt gas injection Water Alternating Gas Y AIO 25A.020 2/2/2022 Y S-217 Water alt gas injection Water Alternating Gas Y AIO 25A.006 4/14/2010 Y S-218 Water alt gas injection Water Alternating Gas Y AIO 25A.004 4/14/2010 Y W-207 Water alt gas injection Water Alternating Gas Y AIO 25A.012 9/11/2012 Y W-209 Water alt gas injection Water Alternating Gas ---Y Approved under original issue of AIO 25A.000 W-210 Water alt gas injection Water Alternating Gas Y AIO 25A.015 9/11/2012 Y W-212 Water injection, single completion Produced Water Injector N --Y Not tied in to MI service W-213 Water alt gas injection Water Alternating Gas Y AIO 25A.017 5/5/2014 Y W-214 Water alt gas injection Water Alternating Gas Y AIO 25A.002 4/14/2010 Y W-215 Water alt gas injection Water Alternating Gas ---Y Approved under original issue of AIO 25A.000 W-216 Water alt gas injection Water Alternating Gas Y AIO 25A.005 4/14/2010 Y W-217 Water alt gas injection Water Alternating Gas Y AIO 25A.003 4/14/2010 Y W-218 Water alt gas injection Water Alternating Gas Y AIO 25A.007 4/14/2010 Y W-219 Water alt gas injection Water Alternating Gas Y AIO 25A.008 3/9/2011 Y W-220 Water alt gas injection Abandoned Y AIO 25A.009 2/21/2011 Y P&A'd for sidetrack W-220A Unknown Water Alternating Gas N --Y New drill AIO 25A compliance risk. Will start on PW service 3/2025. AA request for MI will be submitted 3/2025 to AOGCC W-221 Water alt gas injection Water Alternating Gas Y AIO 25A.014 9/11/2012 Y W-223 Water alt gas injection Water Alternating Gas Y AIO 25A.013 9/11/2012 Y W-04 Water injection, single completion Produced Water Injector N --Y Not tied in to MI service W-01A Oil well, single completion Abandoned N --Y P&A'd for sidetrack W-01B Unknown Water Alternating Gas N --Y New drill AIO 25A compliance risk. Has only been on PW service. AA request for MI will be submitted 3/2025 to AOGCC 04/18/2020 PBU change of operatorship from BPXA to Hilcorp North Slope. 07/01/2020 10/10/2020 Unauthorized injection of PWI into L-109 Orion pool. 12/28/2019 Page 1/2 4/3-4/21/2023 S-201A, S-210 Misinjection Investigation Timeline 3-1 Lack of Knowledge of Hazards Present 04/14/2020 CF Opportunity for Improvement Critical/Causal Factor OFICorrective Action System Cause Immediate Cause 01/06/2020 L-109 investigation letter sent to the AOGCC 06/28/2023 S-201A unauthorized injection of MI. No application or approval from the AOGCC as required by Polaris AIO 25A to place the well on MI. S-210 drilled and completed as a WAG injector. S-201A drilled and completed as a WAG injector. S-210 initially placed on injection, on PWI service. S-210 unauthorized injection of MI. Self report L- 109 to the AOGCC. 4/21/2023 3-1 Lack of Knowledge of Hazards Present 7-1 Inadequate Knowledge Transfer. Individual making decisions was unaware of requirements. 14-1 Lack of PSP, due to deficiencies. No process in place for RE and OE verification of AIO requirements. 7-3 Inadequate Training Effort. Injection CBT exists, but was not assigned and not specific to Polaris Pool AIO. Subsurface team decided to put the well on MI for EOR in Polaris. Additional MI approval required in Polaris AIO but not Orion AIO Unclear why subsurface team did not seek approval prior to injection of MI. Covid and operator transition staff reductions may have degraded preexisting work process Create summary AIO & CO Pool summary, controlled documentation . Maintain 6- month review and approval by Land and ATL. Both RE and OE unaware of the Polaris Pool AIO required additional approvals for MI Subsurface team decided to put the well on MI for EOR in Polaris. MI utilized routinely for EOR in PBU Schrader Bluff formation (Polaris & Orion Pools). Required MI approval for Polaris MI injection not obtained 5-1 Inadequate guards or protective devices OE/RE onboarding training including AIO/CO and pool rules summary prior to initiating injection changes Action to Prevent Recurrence: Training of Operations and Reservoir Engineers will be performed to familiarize them with information resources regarding well pool authorization and wellbore schematics and AKIMS updates. Due date= 7/31/2023. Action to Prevent Recurrence: Internal review of all wells completed across multiple zones with stacker packer completions to verify if injection is authorized into each zone. If injection is not authorized, the wellbore schematic and AKIMS will be updated to reflect this. Due date= 7/31/2023. Review found S-104 misinjection. Subsequent RE/ OE review of Polaris Injectors failed to recognize that existing AA’s for S-201A and S-210 were due to the well completions and not an AA for authorization of MI in the Polaris Pool. CFCF Proposed Corrective Action Request amendment to AIO 25A to provide consistency in regulation between Polaris and Orion pools (Schrader Bluff) Lack of required MI approval not detected as part of handover to HNS Both RE and OE unaware of the Polaris Pool AIO required additional approvals for MI Request amendment to AIO 25A to provide consistency in regulation between Polaris and Orion pools (Schrader Bluff) OFI Page 2/2 CF Opportunity for Improvement Critical/Causal Factor OFI Corrective Action System Cause Immediate Cause Discovery of S- 201A and S-210 unauthorized injection of MI into the Polaris pool. 12/12/2024 S-201A, S-210 Misinjection Investigation Timeline 08/30/2023 S-104 Investigation letter sent to AOGCC. Action to Prevent Recurrence: Development and implementation of an injection well tracking resource to document authorized injection zones, injection fluids and commingled injection on an individual well basis in PBU. Due date= 10/1/2023. S-104 misinjection of MI into the Polaris pool, unauthorized commingled injection on MI into Aurora/ Polaris pools. 7/15-7/21/2023 Self report S- 104 to the AOGCC. 07/21/2023 RE/ OE review of Polaris Injectors failed to recognize that existing AA’s for S-201A and S-210 were due to the well completions and not an AA for authorization of MI in the Polaris Pool. CF Proposed Corrective Action 11-6 Inadequate correction of prior hazard / incident – RE/OE review effectiveness impacted by same lack of knowledge of hazards present as original failure. 4-1 Improper decision making or lack of judgement Apply HAK-3254 Incident Investigation Procedure Methodology going forward. Implement Tiering of WI Integrity or compliance incidents with corrective action alignment with management Add a quarterly CTM task for RE/OE review of injection well tracking resource to ensure accuracy and knowledge transfer from experienced personnel 1 Alaska Oil and Gas Conservation Commission 333 West Seventh Avenue Anchorage, Alaska 99501-3572 Main: 907.279.1433 Fax: 907.276.7542 www.aogcc.alaska.govFebruary 4, 2025 CERTIFIED MAIL RETURN RECEIPT REQUESTED 7018 0680 0002 2052 9501 Mr. Oliver Sternicki Well Integrity Supervisor Hilcorp Alaska, LLC 3800 Centerpoint Drive, Suite 1400 Anchorage, AK 99503 Re: Docket Number: OTH-25-006 Request for Information Notice of Investigation Injection of unauthorized fluids Prudhoe Bay Unit S-201A (PTD 2190920) and S-210 (PTD 2190570) Area Injection Order (AIO) 25A Prudhoe Bay Field, Polaris Oil Pool Dear Mr. Sternicki: On December 12, 2024, the Alaska Oil and Gas Conservation Commission (AOGCC) was notified by Hilcorp Alaska, LLC (Hilcorp) of enriched hydrocarbon gas injection into the Polaris pool without authorization per Rule 2 ofArea Injection Order (AIO) 25A. Hilcorp states that “no record has been found of requested authorization required under Rule 2 of AIO 25A for enriched hydrocarbon gas injection for either well”. According to Hilcorp, wells S-201A and S-210 were permitted as WAG injectors in the Polaris pool and drilled/completed in late 2019/early 2020 by the previous operator. S-201A commenced enriched hydrocarbon gas injection in April 2020 under the previous operator, while S-210 began enriched hydrocarbon gas injection in October 2020 under Hilcorp North Slope operatorship. Both wells have undergone multiple WAG cycles since 2020, with accurate injection types and volumes consistently reported to the AOGCC. As of December 12, 2024, S-210 was offline due to the drilling of wells M-206 and M-207, and S-201A was shut-in to transition to water injection. The facts reported by Hilcorp indicate a failure to operate these wells in compliance with the requirements specified in Area Injection Order 25A, Rule 2:“The underground injection of enriched gas for enhanced oil recovery is authorized only in the following wells: S-215i, W-209i, Docket Number: OTH-25-006 February 4, 2025 Page 2 of 2 and W-215i. Upon proper application, the Commission may approve additional wells for injection of enriched gas within the Polaris Oil Pool.” Pursuant to 20 AAC 25.300, within 30 days after receipt of this letter, the AOGCC requests the following additional information be provided by Hilcorp. 1. The number of days S-201A and S-210 were on enriched gas injection without AOGCC authorization; 2. The total volume of enriched gas injected into S-201A and S-210 without AOGCC authorization; 3. 12 month TIO raw data (excel format) and pressure plot identifying TIO pressures, injection rate, injection temperatures, and any bleed events of S-201A and S-210; 4. Full root cause analysis, including results and conclusions, addressing the failure and corrective actions to avoid recurrence; 5. Results of a review of each of the Hilcorp injectors authorized by AIO 25A (which includes any issued administrative approvals) specifically to the authorization of approved fluids and WAG status, and identification of any wells that are out of compliance; and 6. Any supplementary information, including relevant data and correspondence, that Hilcorp wishes to submit on their behalf. The AOGCC reserves the right to pursue an enforcement action in this matter according to 20 AAC 25.535. Failure to comply with this request is itself a regulatory violation. Should you have any questions about this investigation notice, please contact Jack Lau at 907-793- 1244 or jack.lau@alaska.gov. Sincerely, Jessie L. Chmielowski Gregory C. Wilson Commissioner Commissioner cc: Tim Mayers, US Environmental Protection Agency, Region 10 Jim Regg, AOGCC Phoebe Brooks, AOGCC Mel Rixse, AOGCC Jessie L. Chmielowski Digitally signed by Jessie L. Chmielowski Date: 2025.02.04 11:31:30 -09'00' Gregory C. Wilson Digitally signed by Gregory C. Wilson Date: 2025.02.04 12:34:57 -09'00'