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Tending the giant
Hilcorp submits 2022 POD for Prudhoe Bay IPA, as many as 11 new wells planned
Kristen Nelson Petroleum News
Hilcorp North Slope took over as operator at the Prudhoe Bay unit July 1, 2020, after acquiring BP Exploration (Alaska)’s assets, including its share of Prudhoe, the state’s largest oil field. Hilcorp’s business is taking over mature fields and maximizing production of remaining reserves - obviously the goal at Prudhoe.
Its March 31 submittal of a proposed 2022 plan of development for the initial participating areas at Prudhoe describes work under the existing 2021 POD, the first Hilcorp submitted, and work planned for the 2022 POD, which will be effective July 1 through June 30, 2023.
In its approval of the 2021 POD the Alaska Division of Oil and Gas said Hilcorp North Slope, the Prudhoe operator, has a 26.36% interest at the field.
The company operates on behalf of itself and the other working interest owners: ExxonMobil Alaska Production, 36.4%; ConocoPhillips Alaska, 36.08%; and Chevron U.S.A., 1.16%.
The Prudhoe Bay initial participating areas, IPA, are the gas cap participating area and the oil rim PA.
IPA development began in 1968 with the Prudhoe Bay State No. 1 exploratory well, Hilcorp said, with regular production beginning in June 1977.
The gap occurred because there was, initially, no way to move the oil to market, requiring approval and construction of the trans-Alaska oil pipeline.
Produced water production began in June 1977, Hilcorp said, along with oil production. Large-scale waterflood for secondary recovery began in August 1984, followed by use of miscible gas for water-alternating-gas injection, WAG, in 1987, for tertiary recovery.
2021 production Hilcorp said the IPA portion of Prudhoe produced some 2,780 billion cubic feet of natural gas during calendar year 2021 and 58,839 thousand barrels of oil, with average daily production of 161,203 barrels per day. There were 830 producers and 223 injectors contributing to production or injecting water and gas during the year in the IPA.
In addition to gas and oil, the IPA produced 16,682 thousand barrels of natural gas liquids, with 1,238 thousand barrels sent to Kuparuk.
Returning wells to service “A focus on returning idle wells to service, optimizing production through the existing surface infrastructure, and improved operational efficiency (+1.7%) led to an increase in fluid handling from calendar year 2020 to calendar year 2021,” Hilcorp said.
Thirteen wells were optimized or returned to service by rig workovers in the IPA in 2021 and there was an improvement in NGL volumes “resulting from successful crude cooling project execution and amendment to the Pump Station 1 crude volatility restrictions,” the company said. Annual average NGL sales to Kuparuk ended in August 2021.
These efforts combined, Hilcorp said, “allowed the IPA to remain on the improved production trend established in 2020.”
In 2021 gas production was up by 52 million standard cubic feet per day over 2020 and water production was up by 65,000 bpd, with IPA online wells increased by 18 from 2020 to 2021.
Gas cap water injection Hilcorp said there was a significant increase in gas cap water injection, GCWI, in 2021, more than 74,000 bpd of water over 2020, through multiple efforts including facility maintenance which increased plant reliability and continuation of the sea water optimization plan, SWOP, which re-routed Flow Station 1 seawater injection to GCWI beginning in 2020.
Hilcorp said that in October the Alaska Oil and Gas Conservation Commission approved an increase in annual average injection rates - the previous limit had been 650,000 bpd - enabling the annual average GCWI rate to increase to 707,000 bpd in 2021.
Gas injection was 2,534 bcf in 2021 (2,476 bcf of dry gas and 58 bcf of MI), water injection averaged 1,817,000 bpd and seawater injection 724,000 bpd for an average daily GCWI rate of 707,000 bpd.
2021 drilling Hilcorp said initially no IPA drilling was approved by the working interest owners for the 2021 POD because of “the challenging economic conditions related to the COVID-19 global pandemic,” but after the oil price recovered mid-year, a drilling program was approved.
No wells have been drilled in the IPA under the 2021 POD, but two wells will likely be drilled and completed during the plan period, “depending on rig schedule flexibility,” the company said. The wells are coil tubing sidetracks, E-26B, a producer, and 06-21C, an injector.
Hilcorp said it anticipated completing as many as 15 workovers or recompletions during 2021, with nine wells worked over to date, six to restore tubing integrity:
*18-26B, producer
*07-05, producer
*R-40, producer
*H-21, producer
*Q-07B, producer
*Q-05A, producer
Two wells were worked over to install autonomous inflow control devices, AICD, retrofit liners to control high gas to oil ratio, HGOR, production:
*C-29B, producer
*D-35, producer
One well was recompleted from the IPA to the Polaris pool:
*S-15, injector recomplete to Polaris pool
“All the workovers in the IPA, except for S-15, were a mechanical success,” Hilcorp said, and the wells were put back online, “returning to their prior production capacity. The AICD liner retrofits were a technical success proving the viability of AICD technology for HGOR production optimization.”
Eleven workovers are planned for the remainder of the 2021 POD period, although Hilcorp said rig schedule flexibility may result in more or fewer workovers. The 11 include nine producers and two gas injectors.
The company said non-rig interventions increased in 2021, occurring in 855 wells to date during the 2021 POD. “Excluding annular communication work and surveillance drifts for subsidence monitoring, 501 IPA wells experienced well intervention work. Most of this work was completed to maintain the well stock or increase existing production through well enhancement activities,” Hilcorp said.
2022 proposed drilling Up to 11 new wells are anticipated for the 2020 POD period, with candidates included, but not limited to:
*Two to three producers targeting the Ivishak at W Pad
*One to two producers targeting the Ivishak or Sag River at H Pad or N Pad
*One to two producers targeting the Ivishak or Sag River at Drill Site 11
*Two to four producers targeting the Ivishak at Drill Site 03 or Drill site 09
2022 proposed wellwork, workovers Hilcorp said it anticipates “flat to slightly increasing well intervention activity” during the 2022 POD, with a focus on maintaining existing well stock and increasing production “through non-rig rate enhancement work.”
As many as 20 workovers and/or recompletions are anticipated, focused on wells that have failed mechanically, but there may be one to two “AICD liner retrofits and profile modifications or injector/producer conversions.”
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