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ADEC issues Anna incident final report Says up to three gallons of gas condensate from Anna platform spilled into the waters of the Cook Inlet when platform jolted by ice Alan Bailey Petroleum News
The Alaska Department of Environmental Conservation has issued a final situation report on the April 1 oil spill incident at Hilcorp’s Anna platform in Cook Inlet. The report says that an estimated three gallons or less of natural gas condensate were released to the environment and that the condensate originated from the platform’s gas flaring system. Hilcorp is taking corrective action to prevent a similar discharge in the future, the report says.
On April 1 the company shut down crude oil production from the Anna platform in its Granite Point field after personnel on the platform felt an impact and observed a sheen and bubbles near one of the platform legs where an eight-inch crude gathering line between the Anna and Bruce platforms is located.
The unified command for the incident stood down a couple of days after the incident occurred, once it had been established that no further oil sheening from spilled fluids could be observed in the water near the platform.
Investigation At first blush it appeared that a leak in the pipeline had caused the problem. As a consequence, oil was removed from the line and the line was shut in. However, pressure testing of the line and an inspection by divers demonstrated that the line was, in fact, intact. A subsequent investigation by Hilcorp determined that the spilled fluid had originated from the Anna platform’s fuel gas flare system during maintenance of this system. When ice jolted the platform, the fluid had been knocked out of the system and into the water of the inlet, Hilcorp said.
Hilcorp has said that in future it will prevent a recurrence of the problem by using a different source of gas for the flare’s pilot when conducting flare system maintenance.
According to ADEC’s situation report, Hilcorp has said that the gas feed line that the company had been using during the flare system maintenance can hold a maximum of eight gallons of fluid and that five gallons of fluid had been removed from the line following the spill incident. That would have left a maximum of three gallons of fluid for the spill, ADEC reported.
Restart authorized Following clarification of the cause of the incident, on April 28 ADEC authorized the restart of the Anna platform and its associated subsea oil pipeline. However, the agency required careful monitoring for any fluid leakage during the startup operation. The federal Pipeline and Hazardous Materials Safety Administration also approved the restart.
The ADEC report also says that on May 1 PHMSA withdrew its corrective action order for the incident, saying that PHMSA had conducted a thorough review of Hilcorp’s documentation that characterized the fluid release as originating from components on the Anna platform, and not from a regulated flow line.
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