Kuparuk pipeline leak spills oil-water mixture

ANCHORAGE, Alaska, Dec 17 (Reuters) - A pipeline leak has spilled 4,284 gallons of an oil-water mixture at the ConocoPhillips (COP.N)-operated Kuparuk field on Alaska's North Slope, state officials said on Monday.

The spill was discovered early Sunday morning, the Alaska Department of Environmental Conservation said.

Three drill sites that feed into the affected pipeline were shut in to aid in the response, ConocoPhillips spokeswoman Natalie Knox said. Normal combined production from the sites is 12,000 barrels a day, she said. "Normal production should be restored within about a week," she said.

Preliminary investigation showed that the leak came from a small hole beneath the pipe's insulation, Knox said. "It appears to be isolated external corrosion," she said.

The pipeline, 24 inches in diameter, carries a mixture of oil, produced water and natural gas, said Leslie Pearson, spill prevention and emergency response manager for the Alaska Department of Environmental Conservation.

The spilled material has affected an area of tundra measuring about 1,200 square feet, Pearson said. There was only about six inches of snow on the ground, so the warm oil-water mix melted right through to the tundra, she said.

Production at Kuparuk, the second-largest oil field in the nation, averaged about 151,000 barrels a day in November, according to local news reports. (Reporting by Yereth Rosen; Editing by David Gregorio)