The state is deepening its investigation into what caused several accidents at Prudhoe Bay wells operated by oil company BP.
In a recent order, the Alaska Oil and Gas Conservation Commission, a state oil and gas watchdog agency, said BP “has no evidence that permafrost subsidence will not result in sudden catastrophic failure” at other Prudhoe Bay wells.
The first accident happened in 2017, when a well at Prudhoe Bay jumped up, hit the top of the wellhouse and started spewing oil and gas. It leaked for days before it was stopped. Both the state and BP investigated the incident and linked it to thawing permafrost and the well’s design.
BP’s theory was that the only wells at risk were of a certain design; there’s a relatively small number of those wells at Prudhoe Bay. BP told the state 14 such wells were at risk and they were all shut in.
But in December, there was another accident at one of the 14 at-risk wells and the Alaska Oil and Gas Conservation Commission required another investigation.
After hearing testimony from BP, the commission issued an order last week stating the company has not proven that thawing permafrost won’t lead to more accidents at wells with a more common design, which accounts for most of the 1,800 wells at Prudhoe Bay.
Cathy Foerster, who sits on the state commission, said while there’s no evidence either way, the commission wants to be proactive.
“That’s why we’re ordering BP to gather additional data on those wells so we can gain an understanding of whether or not there is a risk associated with those wells also,” Foerster said.
“We haven’t had anything to cause us to believe that they do have a risk, but we just want to make sure they don’t,” she added.
Among other things, the state is requiring BP to pull up oil well parts, like production tubing and casing, from deep underground to analyze what might have caused the accidents.
The commission is also requiring the 14 wells BP previously said were at risk to be not just shut in, but plugged and abandoned — meaning they won’t produce oil ever again.
According to BP, those 14 wells are being monitored in real time and their flowlines and wellhouses have been removed to prevent future accidents. BP has also proposed plugging and abandoning four additional wells next year, on top if the state’s requirements.
In an emailed statement, BP spokesperson Megan Baldino said the company is working with the state to comply with the order and “remains committed to operating Prudhoe Bay in a safe, reliable and compliant manner.”
Lois Epstein, an engineer with the Wilderness Society, said it’s worrying the state doesn’t know exactly what’s going on.
“When a regulatory agency says there can be a ‘sudden catastrophic failure’ – and that’s the language they use – that’s of great concern,” Epstein said. “If I were working on the Slope near any one of these wells, I would want to know that. I would want to know why there is so much uncertainty.”
BP’s theory is that the heat of fluids in the wells was causing the permafrost to thaw. But now that the state is expanding the investigation, Epstein said she thinks it’s important to look at other potential risks, like permafrost thaw linked to climate change.
BP has been taking measurements to better understand permafrost thaw at Prudhoe Bay since 2011.