ANCHORAGE A corroded pipeline ruptured on Christmas Day at ConocoPhillips' Kuparuk oil field in Alaska, causing one of the biggest-ever spills of oil-laced water on the North Slope, the Alaska Department of Environmental Conservation (DEC) said on Tuesday.
The 94,920-gallon spill from a corroded water-injection pipeline had little effect on production from North America's second-biggest field and was mostly cleaned up by Tuesday, department officials said.
One well was shut in after the spill was discovered, said Ed Meggert, the Fairbanks-based on-scene spill response coordinator for the DEC.
"It remains shut in, and the repairs aren't done yet," he said.
The Kuparuk field can produce nearly 150,000 barrels of crude oil per day.
The December 25 incident was reminiscent of a 200,000-gallon crude oil spill at BP Plc's nearby Prudhoe Bay oil field in 2006 -- the worst oil spill on Alaska's North Slope -- which was also caused by corrosion of a pipeline.
Cleanup was largely accomplished by removing contaminated snow and ConocoPhillips took the leaky pipeline out of service to replace it, said Paul Lhotka, an environmental program specialist with the DEC.
A ConocoPhillips official was not available to comment.
"It was lightly misted produced water and it was only on the surface, and it did not penetrate the snow cover," Lhotka said. Had the spilled material touched the tundra, it could have required a more complex cleanup, he said.
Salty produced water can be toxic to tundra plants and cause long-lasting environmental damage.
The Kuparuk oil field was the site of a much smaller corrosion-caused spill of oil, gas and other fluids about a year ago, according to state records.
The Kuparuk field is North America's second largest, after Prudhoe Bay. ConocoPhillips is the operator and majority owner. BP has a 39 percent ownership share; Exxon Mobil and Chevron own minor shares.
A much smaller spill also occurred this week at BP's Milne Point field elsewhere on the North Slope.
The Milne Point spill was discovered Monday, the DEC said. About 6,300 gallons of a produced water-crude oil mixture spilled because of an overflow of a sand slurry tank at the field's central facility pad, the department said.
BP spokesman Steve Rinehart said Tuesday there was no impact to production at Milne Point.
The spill was entirely contained on the gravel pad, Lhotka said.
(Reporting by Yereth Rosen; Writing by Richard Valdmanis; Editing by Walter Bagley)