Hilcorp Alaska has plugged and abandoned an offshore Cook Inlet well, 17589-1A, drilled as a relief well in 1962.
P&A for wells no longer in production and with no future utility is a routine requirement for companies working in Alaska.
The P&A Hilcorp Alaska just completed was not routine.
It involved a legacy well in more than 100 feet of water which had 1960s era wellhead equipment for which replacement parts were no longer available.
"I'm incredibly proud of our team for executing such a complex and challenging project," Hilcorp Alaska Senior Vice President Luke Saugier said in a statement. "Hilcorp's goal is to be the best operator of mature oil and gas assets. A crucial part of that is making significant investments to safely decommission end-of-life infrastructure and properly plug and abandon wells."
What is routine
Hilcorp Alaska has an ongoing plug and abandon program in Cook Inlet for wells no longer in production and Saugier discussed that program in a presentation to the Cook Inlet Regional Citizens Advisory Council almost two years ago, in September 2021.
He said then that the company would systematically work through inlet wells that need to be P&A'd, doing some work every year.
Hilcorp has a program underway authorized by the Alaska Oil and Gas Conservation Commission for platform wells, with work continuing to P&A wells on the Dillon and Baker platforms in the Middle Ground Shoal unit and work scheduled next year for the Spark and Spurr platforms in the North Trading Bay unit.
Regular P&A is the way Hilcorp does business, Saugier said in that 2021 presentation: The company doesn't want to get to the end of field life with nothing done, he said. And, he told CIRCAC, Hilcorp's vision is that it is the last owner -- it does not intend to sell its assets to someone further down the food chain.
17589-1A
Work to P&A the 17589-1 relief well, the 17589-1A, was complicated, as related in some detail in Hilcorp's filings with AOGCC for permits necessary to perform the work.
The 17589-1A is the relief well drilled after Pan American's 17589-1 blew out in 1962 near the present site of the Tyonek platform.
The state had wanted the well properly P&A'd but that work hadn't been done when Hilcorp took over, acquiring operatorship of the well as part of its acquisition of some of ConocoPhillips' Cook Inlet assets in 2016.
Planning was required, but by 2021, work was underway in the inlet.
Paul Mazzolini, a drilling engineering advisor for Hilcorp in Alaska, talked about the first year of work in the inlet on that P&A at the 2021 CIRCAC meeting.
Lower zones of the well, Mazzolini said, had been abandoned, but surface cement was not put in place for permanent abandonment. It was that job Hilcorp set out to do in the summer of 2021.
He said Hilcorp mobilized the Spartan 151 from the Rig Tenders dock in early June and moved to the 17589-1A for P&A work.
The company mobilized a team of specialists for subsea work and also had Wild Well Control, specialists in accessing old wells and blowout locations.
But it was vintage 1960s equipment on the well and there were no longer any spares or any real information, he said.
Once they got onto the well, they found that the wellhead didn't have the functional equipment needed. After trying to fix that equipment in Nikiski, Hilcorp sent it to Texas to get help from a wellhead specialist to basically reverse engineer the equipment and retrofit it so it would function for P&A work.
Hilcorp reports to AOGCC indicate its personnel inspected rebuilt components in Louisiana in 2021, and new seals were manufactured over the winter.
In 2022, using a custom LiDAR "blackwater box," divers scanned the sealing section of the subsea wellhead, data used to make a model, from which the wellhead specialist was able to complete their design. Custom seals could not be obtained in time for a fall 2022 installation, and AOGCC agreed to an extension over the winter, allowing for manufacture and testing, which was completed in March, with installation in early May, allowing the Spartan 151 to complete P&A work.
AOGCC is currently showing the well as P&A'd, with a last status date of July 11.
State's interest in P&A
AOGCC records show that the state's desire to have the 17589-1A plugged and abandoned goes back decades. The well, originally called Cook Inlet No. 1A, was renamed in the mid-1960s to reflect the state lease number.
There were several issues, among them a change of operators and, more recently, when companies started to work the issue, the lack of an available jack-up in Cook Inlet, a requirement for doing the work.
By the 1970s, Phillips Petroleum Co. had taken over as operator and the state was querying that company on its plans for the well, while indicating it had previously corresponded with Amoco Production Co./Pan American.
When Phillips Petroleum reported 17589-1A as permanently abandoned, AOGCC told the company there was an absence of plugs shallower than 3,150 feet, and thus the well was not properly abandoned.
Conoco and Phillips merged in 2001 and by 2009 the commission was noting a revision of its regulations on suspending wells and asking that ConocoPhillips verify suspended wells operated by the company and its predecessor.
In 2010, ConocoPhillips reported a well inspection by divers for 17589-1A, telling the commission that the wellbore had been isolated for more than 40 years from the surrounding formations "without loss of integrity and has not allowed migration of fluid that could threaten public health or impair the recovery of oil or gas."
The company requested extensions on the commission's requirements to P&A the well and conducted inspections using divers.
One issue that ConocoPhillips cited was the requirement for a jack-up for P&A, and while at some point there were two jack-ups in the inlet, by 2015 one jack-up had left and the other was under contract to another operator.
The jack-up issue continued after Hilcorp took over, but that company combined use of the Spartan 151 in the P&A effort and to drill wells at the North Cook Inlet field, which is also acquired from ConocoPhillips.
