Hilcorp continues to monitor gas leak

Company monitoring ice conditions over leaking subsea gas pipeline in Cook Inlet and has minimized gas flow through the line

ALAN BAILEY

Petroleum News

In response to the discovery of gas leaking from an 8-inch gas line on the seafloor of Cook Inlet, Hilcorp Alaska is continuing to conduct daily overflights of the leak location, weather permitting, to monitor sea ice conditions and determine when it will be safe to conduct diving activities to investigate the leak, the Alaska Department of Environmental Conservation reported Feb. 21 in its second situation report for the gas leak incident.

As previously reported in Petroleum News, the leak was discovered on Feb. 7 by a Hilcorp helicopter at a location between Nikiski on the Kenai Peninsula and Platform A of the company’s offshore Middle Ground Shoal oil field. The pipeline, which lies in a water depth of 80 feet, supplies dry processed fuel gas consisting of 98.67 percent methane to the A, C, Dillon and Baker platforms.

In a Feb. 16 press release, Hilcorp said that it was continuing to work in cooperation with multiple state and federal agencies to ensure a safe and effective response to the leak.

“At present, ice conditions in the Cook Inlet continue to prevent divers from accessing the pipeline safely,” Hilcorp said. “The safety of our personnel and the environment remain a top priority as we work to respond to the leak.”

Meanwhile crews have shut down non-essential equipment on the platforms to reduce the gas flow through the line to the lowest possible gas pressure that does not jeopardize safety. Some positive pressure is needed in the line to ensure that any residual hydrocarbons in the pipe are not released into the waters of the inlet, in particular to prevent the escape of any residual crude oil in the line. Apparently, the line had previously been used for the transportation of crude oil.

“Shutting in the line presents safety risks for our people, the environment, and has the potential to further damage offshore infrastructure,” Hilcorp said.

The daily overflights of the leak have not observed any oil sheen on the water, Hilcorp said. It is estimated that some 210,000 to 310,000 cubic feet per day of gas are escaping from the line.

The ADEC report says that on Feb. 16 the agency facilitated a meeting with other state agencies, and with the federal agencies that act as natural resource trustees, to discuss resources at risk in the vicinity of the gas leak. Those resources include the neighboring shoreline habitats; marine mammals, including Cook Inlet beluga whales; numerous birds, including the protected Steller’s eiders; and several fish species and fish life stages. The report did not indicate what risk the leaking gas might pose for the wildlife and their habitats.