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Hilcorp has fuel line leak in Cook Inlet
Kristen Nelson Petroleum News
Hilcorp Alaska has reported a fuel gas leak in Cook Inlet.
“On April 1, 2021, a Hilcorp helicopter observed a release from a fuel gas pipeline connected to our Middle Ground Shoal offshore facilities,” Hilcorp Alaska spokesman Luke Miller said in an April 6 email to Petroleum News.
The Alaska Department of Environmental Conservation released a situation report on the leak April 5. DEC said the release was spotted at about 4:25 p.m. April 1 by a helicopter pilot during supply delivery and reported by Hilcorp to the National Response Center and DEC at 5:30 p.m. that same day.
Miller said that in addition to notifying appropriate agencies the company “immediately began shutting in the impacted facilities.”
DEC said the product being released is processed dry natural gas which is 98.67% methane, used as fuel gas for two platforms, A and C. The department said the amount released into the water is not known as this time. It said Hilcorp reported line pressure was approximately 190 psi prior to the release and as of April 2 the company had reduced the line pressure to 70 psi.
“No sheen has been observed. An assessment of the source of the leak is ongoing. No personnel or wildlife have been impacted,” Miller said in the company statement.
Plans Miller said Hilcorp is “monitoring ice conditions and will perform side scan sonar to gather further data on the repair location. Divers will be deployed mid-week to install a temporary clamp.”
DEC said the 8-inch line, which had a leak in 2017, is some 80 feet below the surface of Cook Inlet. The department said Hilcorp achieved source control April 3 at about 1:30 p.m. by activating the block valves and said diving operations to identify the reason for the leak will begin when ice conditions allow.
Previous leaks Hilcorp installed a permanent repair in May 2017 for the fuel gas leak on this line between Platform A and Nikiski which occurred in February 2017. The leak was determined to have been caused by a large rock which caused a breach in the line.
That leak was discovered when Hilcorp conducted helicopter surveillance flights in response to observed anomalies in pipeline flow data.
Following the 2017 leak, Hilcorp had to shut down the Middle Ground Shoal field until repairs could be made, which began with installation of a temporary clamp in April.
The company’s business model focuses on bringing new life to aging oil and gas assets.
Platform A in the Middle Ground Shoal field is the oldest in the inlet, installed in 1964. Platform C at Middle Ground Shoal was installed in 1967. The line currently being used to transport fuel gas is encased in concrete; it was installed in 1965 and its design does not allow use of in-line inspection tools.
The line was pressure tested in 2005 and Hilcorp conducts annual side-scan or multi-beam echo-sounder surveys, but those do not provide enough information to allow the company to determine whether there are problems such as eroded pipe, rock impingements, dents, gouges or missing concrete coating.
The federal Pipeline and Hazardous Materials Safety Administration noted in 2017 that this line suffered two previous leaks, the earliest in 2014.
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