Unocal has responded to a sheen in the vicinity of the McArthur River field King Salmon platform in Cook Inlet by shutting in the platform and preparing to hydrotest an 8-inch subsea crude oil pipeline which carries oil from the platform to the Trading Bay production facility on the west side of Cook Inlet. There is also an 8-inch natural gas line connecting the platform to the shore.
The Department of Environmental Conservation said late this afternoon that droplets of oil have been observed adjacent to the platform for about two weeks, but the source had been believed to be equipment on the platform. Yesterday afternoon, DEC said, it was determined that the source was subsea.
Unocal spokeswoman Roxanne Sinz told PNA that it is a small sheen just north of the King Salmon platform.
DEC said the amount and type of oil are unknown. It appears to be bubbling up from a subsea source adjacent to the platform on an intermittent basis. DEC said the bubbling is underneath the flare boom, but the source appears to be beneath the water surface. The oil bubbling was observed at 10:20 this morning and appeared to stop 50 minutes later, producing a sheen approximately 20 feet by 400 yards.
DEC said oil recovery is not possible at this time because of the intermittent release of the oil bubbles and the rapid dissipation of the sheen.
DEC said Unocal is suspending production operations at the King Salmon platform and preparing the 8-inch crude line for hydrotesting. The crude line was hydrotested in February as a precautionary measure following the Dolly Varden platform leak from an 8-inch subsea crude oil pipeline. DEC said that there were no anomalies noted in the King Salmon pipeline in the February testing.
Sinz said that Unocal planned to shut in the platform starting at 4 p.m. this afternoon and to start hydrotesting procedures on the line later today. What Unocal does next, she said, will depend on results from the hydrotest. If the oil is not found to be coming from the crude oil line, the gas line will then be tested.
Sinz said that the sheen has dissipated.