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Unocal has small oil spill at Dillon platform
Kristen Nelson PNA Editor-in-Chief
Unocal discovered a small crude oil leak at its Dillon platform in Cook Inlet at about 2:30 a.m. Nov. 27. The Alaska Department of Environmental Conservation said that the source of the spill was a cracked fitting on the platform’s power oil system — a component of the artificial lift system used to produce oil.
Unocal activated their response contractor, Cook Inlet Spill Prevention and Response Inc. The response vessel SeaBulk Montana was on scene at 6:30 a.m. DEC said that two 90 pound bags of viscous sweep were deployed but negligible oil was encountered. The response vessel Monarch and a 249-barrel oil barge also responded.
DEC said that a pre-dawn over flight using an infrared camera detected oil eight miles south of the Dillon platform during the outgoing tide but that a mid-morning over flight between the Dillon platform and Kalgin Island found no oil or sheen.
Maximum spill 55 barrels of crude DEC said Unocal reported a maximum of 55 barrels of crude oil released, based upon a worst case discharge rate of 0.5 barrels per minute.
Unocal spokesman Kevin Tabler told PNA that Unocal does not believe that 55 gallons of oil was spilled. Tabler said the calculation was done based on maximum pressure at the leak for the entire time from the previous inspection until the leak was found.
But the drop in pressure was not enough to set off the sensor — the leak was found during a visual inspection — so the leak was not occurring at the pressure used to calculate the 55 barrels, and the duration is an unknown, he said.
“We geared up for 55 barrels”, Tabler said, but only trace amounts were recovered and there was no visible sheen at daylight.
The fly over with infrared found something that read as a thermal difference, he said, but after daylight, “they flew for an hour and couldn’t find any sheen at all.”
DEC said that Unocal had shut down oil spill response operations as of 11:30 a.m. and was projecting that the platform would resume operations by 2:30 after repairs and preventative measures were implemented.
Systems in place All the systems were in place on the Dillon, Tabler said.
“This was not enough of a failure to cause an automatic shutdown. It was discovered just exactly as it should have been — on a routine inspection.”
The platform was shut in immediately, he said, agencies were notified and CISPRI was activated. The incident command center was even activated, Tabler said, although by afternoon everyone was on their way home.
Unocal does have some cleanup to do because the spray was on the west side and the wind caught it and sprayed it back on the platform, Tabler said, but repairs were expected to be completed and the platform back online by afternoon.
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