State, feds investigate spill at North Slope’s Lisburne field

Ruptured pipe in BP-operated field releases estimated 45,828 gallons of oil and water; criminal and civil probes under way by Alaska Department of Environmental Conservation, US EPA

Wesley Loy

For Petroleum News

State and federal authorities confirm they’re conducting criminal and civil investigations into a pipeline rupture discovered in the BP-operated Lisburne oil field on Nov. 29.

Weld Royal, spokeswoman for the Alaska Department of Environmental Conservation, told Petroleum News a civil investigation is under way to determine if any pollution laws or regulations were violated.

A criminal investigation also has begun in cooperation with the U.S. Environmental Protection Agency, said Jim Bowden, chief investigator in the DEC’s Environmental Crimes Unit.

The probe is just beginning, and Bowden said it was too early to say whether he’s seen any evidence of a crime.

“We’re just kind of going in to see what’s there,” he said.

Tyler Amon, acting special agent in charge with the EPA’s Criminal Investigation Division in Seattle, confirmed his agency is looking at the Lisburne incident.

BP’s Alaska spokesman, Steve Rinehart, said the company had no comment on the nature of the state and federal probes.

“We cooperate with regulatory agencies,” he said. “We are conducting a thorough investigation of our own.”

Details of the spill

The pipeline, 18 inches in diameter, normally carries a mixture of oil, produced water and natural gas to the production center but was not in operation at the time of the spill.

Investigators found a rupture about two feet long on the bottom of the pipe.

“The rupture is consistent with an overpressure scenario, linked to ice plugs forming inside the pipe,” a Dec. 8 media update said.

The rupture resulted in an estimated spill volume of 45,828 gallons, or about 1,091 barrels, a Dec. 17 situation report from the DEC said. An estimated 8,400 square feet of snow-covered tundra was affected, with no product reaching the shoreline of nearby Prudhoe Bay.

Responders who used jackhammers to remove frozen contaminated material underneath the pipeline have mostly finished the cleanup, the DEC said.

BP on Dec. 21 notified regulators of another spill from a 6-inch well line at Drill Site 6 in the Prudhoe Bay field. An estimate of the size of that spill wasn’t immediately available.

Glare on BP

Ultimately, BP’s local subsidiary, BP Exploration (Alaska) Inc., would plead guilty in late 2007 to a federal misdemeanor under the Clean Water Act. A judge put the company on probation for three years and ordered $20 million in penalties.

Now BP is defending itself against a pair of civil suits the state and federal governments brought against the company in March.

The 2007 environmental conviction wasn’t the first for BP in Alaska.

In 1999, the company pled guilty to a federal felony for not immediately reporting that a contractor, Doyon Drilling, illegally injected hazardous waste such as solvents and paint down well shafts in BP’s Endicott oil field.

BP was fined and put on probation for five years in that case, with the probation period ending in 2005.

Pipe breaks, spilling oil at Prudhoe drill site

BP spokesman Steve Rinehart told Petroleum News Dec. 22 that the pipe had ruptured at a weld and that an on-site BP operator had observed fluid spraying from the break.

“The (well) surface safety valve immediately shut the thing down, so it basically just sprayed and stopped,” Rinehart said.

A unified command was activated and a response team proceeded to delineate the extent of the spill. The response team has confirmed that the leak has stopped and that it is safe to work at the site, Rinehart said.

On Dec. 23 Alaska Department of Environmental Conservation environmental program specialist Paul Lhotka told Petroleum News that the response team had delineated the area of the spill, with 14,000 square feet of the gravel well pad, 158,000 square feet of adjacent snow-covered tundra and 50,000 square feet of the drill site’s reserve pit impacted.

The team had removed 72 cubic yards of contaminated snow, primarily from the gravel pad, he said.

The contamination appears to be in the form of oil misting, heaviest near the pipeline rupture and around the well house, with light misting further out.

“It was a wind-driven release, so as you get to the far end of the plume it thins out quite a bit,” Lhotka yet. No pooled spill products have been identified, he said.

The response team has not yet determined the amount of oil spilled and will use two approaches to assess a spill volume, Lhotka said. One approach is to estimate the spill volume from the extent of the surface contamination. The other approach is to use engineering calculations of fluid volumes, using the capacity of the ruptured pipe.

At this stage, the cause of the pipeline failure is unknown and is the subject of investigation.

—Alan Bailey