ANCHORAGE, Alaska (KTUU) – ConocoPhillips Alaska is estimating the leak at their Alpine site on the North Slope that started over a month ago has released 7.2 million cubic feet of natural gas.
The leak was first observed on March 4, at the CD1 drill site of the Alpine Central Facility on the North Slope, which is operated by ConocoPhillips Alaska. The natural gas was observed releasing from the ground at a well house at the drill site.
“Natural gas releases occurred at 7 wells on CD1 drillsite and through cracks on the pad near Doyon Rig 142,” an updated situation report from the Alaska Oil and Gas Conservation Commission.
The estimated size of the leak had been unknown until recently, but according to the situation report, ConocoPhillips disclosed that 7.2 million cubic feet of gas had been released in an April 1 letter to the commission.
“Once we got it into the hard pipe — the gas into the hard pipe — and piped it into the facility,” said Bruce Kuzyk, vice president of operations for the North Slope. “Then you can meter, monitor it and do the calculation on the actual estimate so that we have it correct.”
Kuzyk said the source of the natural gas leak was 3,000 feet below the surface. The company used a “kill fluid” which was the first step, and then they moved through a series of cement injections to plug the well permanently. The leak was confirmed stopped on March 28, but there is still some gas leaking.
“So at this point in some of the gravel beds around the wells, there’s minimal amount of traceable gas passing through, Kuzyk said. “But we expect that to go to zero here shortly.”
ConocoPhillips initially evacuated about 300 nonessential employees from the Alpine facility when the leak was first reported, leaving a smaller number of essential personnel on site to handle it. This prompted concern among residents of Nuiqsut, just 8 miles away.
The Alpine facility provides Nuiqsut with natural gas for heating homes and other buildings. While there has been no disruption to that production, there were fears early on that if ConocoPhillips had to shut down production at the facility over the leak, that could mean the village would be left with only a few days supply of natural gas.
The evacuation of the Alpine employees also worried residents in Nuiqsut. The mayor previously said several families opted to leave out of an abundance of caution.
Employees that had been evacuated returned to the facility in mid-March, and Kuzyk said Wednesday things are back to normal at the site as they investigate the situation further.
While ConocoPhillips has not released a cause for the gas release, and the cause is still officially listed as “under investigation” in situation reports from the Alaska Oil and Gas Conservation Commission, the company did say the source is a well it was drilling.
“We determined the source was coming up through the annular, the outer annulus of one of the wells that we were in the process of drilling,” Kuzyk said. “So we were able to hard pipe that gas into our facility, the Alpine, so to significantly reduce the release, and run it through the process. And then at that point, we go through … the diagnostics to figure out where the gas is coming from.”
Kuzyk said they have not detected any gas off the facility, and there are no indications of impacts to either the environment or people.
“We have a full investigation team that’s been stood up to look at everything that’s transpired,” Kuzyk said. “And we will learn from this and there’ll be more to come.”
Kuzyk said they expect to have a draft of the investigation in the coming weeks.
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