PRUDHOE BAY, Alaska (AP) -- Alaska's Prudhoe Bay oil field is showing its age.
Corrosion is a constant problem at the oil field on the North Slope, which was built nearly 25 years ago.
Every year there are hundreds of spills on the North Slope. Most of the spills are 10 gallons or less, but the ones caused by corrosion -- although they account for only a few of the spills each year -- tend to be big, averaging more than 4,200 gallons, according to state statistics.
''We recognize this as a serious problem,'' Bill Patterson, Phillips Alaska's Kuparuk field operations manager, told the Anchorage Daily News. ''Over the past several years there has been a major effort to get on top of this.''
This winter there have been four large spills at Prudhoe Bay, and two of those were from corrosion or abrasion.
Last week, a pipeline at Kuparuk ruptured, spilling a hot mixture of salt water and crude onto the tundra. At 92,400 gallons, the spill may be the largest ever to hit the North Slope's fragile tundra.
The timing of the Kuparuk spill was particularly bad. It occurred as the industry is trying to put the best face on its operations to help open the nearby Arctic National Wildlife Refuge to exploration.
The Kuparuk spill was caused by corrosion. Water had seeped between insulation and pipe at a weld joint and ate away the steel.
Over the past 15 years, corrosion and abrasion in the Slope's 2,000 miles of oil, water and natural gas pipelines have worsened.
BP and Phillips currently spend tens of millions of dollars to X-ray pipes, run infrared tests and pump chemicals to control corrosion rates.
BP has agreed to pay $500,000 a year for 10 years to help fund state corrosion experts and increase monitoring.
Susan Harvey, head of oil spill response planning for the state, said no new regulations are planned for now.
''If they have more spills, that's the next step, to regulate them more,'' Harvey said.
Corrosion and abrasion are symptoms of aging oil fields, like Prudhoe, which started up 24 years ago, and 20-year-old Kuparuk. As the oil fields age and production falls, the companies pump seawater underground to boost oil flow. Now vast volumes of water come out of the ground with the crude. The water is mildly acidic and eats at the pipes.
Unlike with big pipes like the 800-mile trans-Alaska oil pipeline, state environmental regulators have little power to ensure the safety of the thousands of miles of lines inside the fields. They also lack the manpower to monitor all lines.
''If we had more presence up there, maybe these problems would come to light sooner,'' said Ed Meggert, state spill coordinator in Fairbanks. ''The companies have been pouring a lot of money into it. Is it enough? I don't know.''
As the oil fields age and produce less, pressure to keep maintenance costs low increases. The motive to cut costs could run counter to protecting the tundra, said Richard Fineberg, a Fairbanks economist who follows the oil industry.
''The idea is to hold maintenance costs just below the cost of cleaning up a spill,'' Fineberg said.
Since 1996, BP's corrosion control budget at Prudhoe has fallen 14 percent, to $37 million this year.
BP's corrosion manager, Richard Woollam, agreed there is pressure to control costs at the aging field but said the shrinking corrosion control budget reflects improved efficiency, such as mixing corrosion control chemicals at Prudhoe instead of incurring shipping costs to the Slope.
Woollam said the company's corrosion program is successful. The company is injecting more chemical inhibitors, and Prudhoe pipeline corrosion rates have fallen. Overall, there is a decreased number of corrosion-related repairs.
Kuparuk field manager Tom Wellman said in an interview last year with the Daily News that then-operator Atlantic Richfield Co. got a wake-up call in July 1997. At a weld joint, meltwater seeped through insulation and settled against a hot oil transportation line.
The water ate at the steel. Eventually, the pipe ruptured, spraying 2,000 gallons of oil over the tundra.
Since then, workers have checked about 67,000 weld joints. Phillips' corrosion budget has climbed 71 percent since 1996 to $24 million.
Wellman said that although pressure to control costs is constant, prevention is cheaper than spill cleanup and repair.
''We can't afford to let these lines get to that point. It's not good business to have these lines fall apart,'' Wellman said.
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