Flow Station 2 has release to flare pit

There was a release of produced fluids and crude oil in the primary flare containment of Flow Station 2 at the Prudhoe Bay field on Alaska’s North Slope July 21. The release was discovered by a BP Exploration (Alaska) employee at 2:30 p.m., the Alaska Department of Environmental Conservation’s Division of Spill Prevention and Response said in a July 25 situation report.

DEC said a BP employee “walked down” the flare field after a black smoke release occurred.

BP Exploration (Alaska) spokesman Steve Rinehart told Petroleum News in a July 27 e-mail that flares are a necessary safety system and the flare pits are designed to accept hydrocarbons.

“The pit is surrounded by a gravel berm to contain these hydrocarbon residues where they can be cleaned up,” he said.

Rinehart said the spill was reportable under state law, but the flare pit “is federally approved as a site where hydrocarbons may be released and subsequently cleaned up.”

He said the spill has been “largely cleaned up,” and BP expects to have the plant back online in the next week.

FS-2 was shut-in one day after the release was discovered, DEC said.

Some 200 gallons

DEC said the flare pits have a bathtub ring of black oil varying from two to 14 inches, with sheen observed in the water.

The FS-2 production facility is in the east operating area of the Prudhoe Bay unit.

DEC said multiple flare lines extend into a designated flare area at FS-2. Normal operations are processed through a continuous burning flare and episodic events of gas surges are directed through other flare piping circuits.

Produced fluids entering FS-2 contain brine water, crude oil, natural gas and other volatile products that are separated into sales grade crude oil, conditioned gas or water for reinjection, DEC said. The final flare piping circuit allows produced fluids that passed into a surge tank during an episodic gas event to release into a six-inch “liquid” flare line.

DEC said the cause of the spill is under investigation.

Rinehart said he didn’t want to speculate on the cause because it is under investigation and could be corrosion, mechanical damage or some other cause, but said “it is fair to say corrosion is always a main suspect when checking the cause of leaks in steel pipe that is exposed to a corrosive environment.”

—Kristen Nelson