Hilcorp’s Anna Platform has resumed work after having been shut down since a suspected oil release April 1. An Alaska Department of Environmental Conservation (DEC) situation report released Saturday states that the platform’s crude oil pipeline to onshore facilities — the suspected source of sheens seen on the surface of Cook Inlet on which prompted the shutdown — was restarted May 2, watched by observers from DEC, U.S. Coast Guard, and the federal Pipeline and Hazardous Materials Safety Administration (PHMSA), who saw no oil releases.
The material spilled April 1 wasn’t crude oil as originally suspected, according to the DEC report, but natural gas condensate — hydrocarbons found in natural gas that become liquid at surface temperatures — and it came not from the oil pipeline but from the platform’s flaring system, used to burn off excess natural gas pumped up along with oil. The release “resulted from an upset condition” in the flare system, according to the situation report.
Hilcorp had previously calculated that three gallons of material were released in the April 1 incident. The DEC report states that this was based on the subsequent discovery of five gallons of liquid in the maximum eight-gallon condensate pipeline.