ANCHORAGE - State environmental protection officials and BP Exploration (Alaska) Inc. are stepping up North Slope pipeline inspections after a spill blamed on corrosion last month.
An estimated 1,500 gallons of crude oil and 4,500 gallons of oily water leaked from a 24-inch pipeline in the Prudhoe Bay oil field where the line passed through a culvert underneath a caribou crossing. The crossing is a gravel mound that allows the animals to traverse pipelines.
Inspectors found that oil and water escaped from three small holes in insulated pipe exposed to water in the culvert, said BP spokesman Daren Beaudo said.
A cleanup on nearly an acre of land affected by the spill has been completed. The land is now flooded with water due to the spring thaw, said Leslie Pearson, prevention and emergency response manager for the state Department of Environmental Conservation.
BP could face a fine but such penalties often hinge on how well a company works to prevent, report and clean up spills, she said. In this case, BP did a good job of attacking the spill, Pearson said.
Cleanup workers were able to recover 500 to 800 gallons of crude oil, she said. The site will be monitored throughout the summer to see how vegetation reacts.
The leak, first reported May 27, forced wells on two Prudhoe production pads to shut down for several days, stopping the flow of up to 10,000 barrels of crude oil a day. BP placed a temporary sleeve around the ruptured section and the pipe is carrying oil again, Beaudo said.
BP spent more than $1 million on the cleanup and repair, he said.
Corrosion is a daunting problem on the North Slope, where thousands of miles of pipeline have been installed over about 30 years of oil field development.
BP has ratcheted up spending to combat corrosion, Beaudo said, and this year has a $40 million budget to find and fight corrosion in the greater Prudhoe Bay field area.
BP has 100,000 locations in its Prudhoe inspection program, including 40,000 sites inspected for external corrosion, Beaudo said. Engineers use everything from X-rays to chemical treatments to spot and ward off the decay.
Pipe can corrode both from outside and within. Last year, Prudhoe Bay had two spills related to external corrosion, Beaudo said.