DEC issues final report on inlet gas leak

Petroleum News

On June 8 the Alaska Department of Environmental Conservation, Division of Spill Prevention and Response, issued a final situation report on Hilcorp’s 2021 natural gas leak, which was reported April 1.

A helicopter bringing supplies to Platform A in Hilcorp Alaska’s Middle Ground Shoal field reported bubbles on the surface at about 4:25 p.m. April 1, and Hilcorp reported a gas leak to DEC at 5:30 p.m.

DEC said the bubbles were not from natural produced from the platform but a processed dry natural gas, 98.67% methane, used as fuel gas on Platform A and Platform C.

DEC said Hilcorp estimates that some 2.6 million standard cubic feet of the fuel gas had escaped before the line was shut-in April 3.

An investigation into the cause of the release is ongoing, overseen by the federal Pipeline and Hazardous Materials Safety Administration, which has jurisdiction over design, construction, operation and maintenance of natural gas pipelines.

The 8-inch pipeline remains shut-in.

When the leak was discovered, DEC said, “Hilcorp immediately shut-in Platforms A and C and began reducing pressure in the natural gas line,” with source control achieved April 3 at about 1:30 p.m. by activating the block valves.

Hilcorp conducted sonar and diving activities to access the damage when ice conditions in Cook Inlet allowed.

DEC said it “determined that there is no risk to the environment following the shut-in of the line,” and said Hilcorp conducted several overflights and observations from the platforms, with no wildlife observed near the surface where the bubbling occurred.

DEC said there is no ongoing release of gas and the line is out of operation until permanent repairs are replaced.

PHMSA has approval authority for repairs, and DEC said it is taking no further response action.

- Petroleum News