Pipeline leak's a doozy
KUPARUK: Crude and saltwater soak tundra in year's biggest spill.

By Ben Spiess
April 17, 2001

In what may be one of the largest spills ever on the North Slope, 92,400 gallons of saltwater and crude oil leaked from a pipeline at the Kuparuk oil field Sunday night.

The mixture, which was more than 97 percent saltwater, leaked from a 10-inch pipeline at a temperature of more than 100 degrees. The spill saturated nearly an acre of tundra, said Ed Meggert, head of oil spill response with the state Department of Environmental Conservation in Fairbanks.

No exact cause has been determined, but Meggert said "it looks like erosion or corrosion to the pipe is the cause." This is the fourth major spill on the North Slope this winter and the second due to erosion or corrosion.

By midday Monday, Phillips, which operates the Kuparuk oil field, North America's second largest, said it had cleaned up most of the spill.

Corrosion from water and erosion from abrasive material such as sand is a growing problem on the North Slope. As Kuparuk and Prudhoe Bay age, the companies are grappling with internal pipe corrosion from water running through lines and external corrosion from water seeping between pipe insulation and hot steel pipe walls, where it eats at the metal.

The accident timing is bad for Alaska's big oil companies -- Phillips, BP and Exxon Mobil -- and state leaders who are trying to put a positive spin on the oil industry's environmental record in an effort to open the Arctic National Wildlife Refuge to drilling. The refuge sits about 90 miles east of existing oil fields and, according to government geologists, may hold the largest undeveloped oil reserves in the nation.

Workers discovered the spill at 10:45 p.m. Sunday when a drop in pipeline pressure set off an alarm in Kuparuk's central processing facility. Within 12 minutes the pipe was shut down, said Phillips spokeswoman Dawn Patience. It is unknown how long the water and oil spilled before the leak was discovered.

The pipe carries what is known as "produced water." For more than a decade, the oil companies have injected saltwater deep into oil fields to boost reservoir pressure and enhance oil flow. As a result, large amounts of water come out of the underground reservoir along with oil and gas. The mixture runs to the processing facility where the gas and most crude oil are stripped off. Then, operators send the water, along with some crude, back to the production pad and re-inject it to keep reservoir pressure high.

The leak occurred in a line that returns the water and trace oil to Kuparuk production pad 1B. The leak happened at a road culvert close to where the pipeline leaves the processing facility's gravel pad, Patience said.

At the time of the spill the weather was 9 degrees Fahrenheit.

While Meggert said that the oil content in the water was low, about 1 percent, the huge spill size means that independent of the saltwater, nearly 1,000 gallons of crude hit the tundra. That crude spill would be one of the 10 largest spills on the North Slope in the past five years, according to state statistics. The high temperature as it left the pipe may mean the mixture penetrated into the ground.

Meggert said the saltwater may be more damaging to the tundra than oil. "It's just as toxic as diesel," he said. "The plants that normally grow die. The crude will only coat but the saltwater penetrates."

By 1 p.m. Monday, Patience said, Phillips and its contractors had cleaned up more than 92,000 gallons of fluid. Much of that may have been snow and ice melted by the hot crude and water mixture.

Meggert said that in the coming days the spill area will likely be diked with sandbags and flooded with freshwater and, possibly, a chemical agent to flush the salt and crude from the tundra.

Meanwhile, the cause of the spill was under investigation. A particular problem in the oil fields is water seeping between thick insulation and the hot transportation pipes. High temperatures and water make a perfect climate for corrosion.

Phillips and BP, which operates the neighboring Prudhoe Bay field, use an array of techniques including X-rays, chemical corrosion prevention and infrared monitoring to detect points of pipeline weakness.

At Kuparuk, Patience said, Phillips spends about $24 million a year on corrosion control. Yet problems persist.

On March 6, more than 3,200 gallons of drilling lubricant spewed across the tundra at Prudhoe Bay after grit carved a hole inside a pipe. In October 1998, an oil-processing building at Prudhoe Bay exploded after natural gas leaked from an eroded pipe. In June 1999, a pipeline ruptured at a Prudhoe Bay production pad due to corrosion, according to state officials.