AOGCC: source remediation continues at CD1

Kristen Nelson

Petroleum News

The April 13 situation report on the natural gas release at Alpine CD1 from the Alaska Oil and Gas Conservation Commission says an open hole cement plug is in place isolating the C-10 (Halo) formation at the WD-03 well.

Alpine is at the western North Slope Colville River unit, where ConocoPhillips Alaska is the working interest owner and operators.

All wells at CD1 remain shut-in except waste injection in well CD1-01A and produced water injection in CD1-02, CD1-03 and CD1-05, AOGCC reported.

Once excess cement has been cleaned out, AOGCC will witness plug integrity verification, the agency’s situation report said.

Source remediation operations began March 30 at the WD-03 disposal well, which was being drilled when the natural gas release occurred.

ConocoPhillips said the C-10 Halo zone of the WD-03 well was not cemented because the interval had not been interpreted “as a significant hydrocarbon zone.”

The gas release was first observed March 4 from the ground at the wellhouse of well CD1-05 and natural gas releases occurred at seven wells on the CD1 drill site and through cracks on the pad near Doyon Rig 142.

ConocoPhillips said April 1 in a letter to AOGCC that the volume of gas which escaped is estimated at 7.2 million standard cubic feet. The company said most of that volume “is believed to have escaped to the atmosphere between March 4, 2022, when gas was first detected at CD1, and March 8, 2022, when gas flow was routed through the WD-03 outer annulus into the” Alpine Central Facility. “Some small amount of gas that was released to the subsurface strata may continue to escape to the atmosphere over time,” the company said.

- KRISTEN NELSON