Pigging held up by leak in pipeline

Petroleum News Alaska Staff

Planned pigging of an old Cook Inlet pipeline has been held up by the discovery of leaks in the pipeline.

The Alaska Department of Environmental Conservation said June 28 that BP Exploration (Alaska) Inc. planned to flush an old pipeline in Cook Inlet June 29-July 1.

DEC said seawater was pumped into the pipeline in preparation for pigging at about 7:30 p.m. June 29, but flow between the pig launcher and shore was not established as expected after pumping for an hour, indicating a leak somewhere in the line.

Compressed air was pumped into the pig launcher early June 30 and bubbles were seen on the surface above the pipeline about 200 feet from where the air was pumped into the line. DEC said pigging operations were suspended; the project team is reevaluating the project plan, which was to use a train of gel and foam pigs to clean residue from the line, following a work plan that DEC said had its approval, as well as that of the U.S. Coast Guard.

DEC said it believes the pipeline, one of two 10-inch lines installed from the Anna Platform in 1966 and acquired by BP as part of the BP-Amoco merger, was responsible for sheens in Cook Inlet last year.

There had been frequent pipeline failures between 1966 and 1972 within four miles of the Anna Platform, DEC said, and in 1974 the crude oil pipeline was shut down and crossed over with the gas pipeline. The pipeline was pigged one time to clean. In 1983 the gas pipeline was also shut down due to leaks. The two lines were abandoned in place by in 1987.