ANCHORAGE - Alyeska Pipeline Service Co. is taking steps to address potentially dangerous vibrations in a newly rebuilt pump station of the trans-Alaska pipeline.
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As a temporary measure, workers have wedged blocks of wood underneath shaky piping at the pump station to add stiffness.
Though wood supports might seem like a crude technique for the pipeline, which this year has carried an average of 761,226 barrels per day, a spokesman for the company said cribbing is common in the industry. Alyeska spokesman Mike Heatwole also said the piping at the pump station is safe to operate even without the cribbing.
The vibration is one of the nagging problems that have plagued Alyeska's campaign to rebuild four key pump stations along the 800-mile pipeline, which began moving Prudhoe Bay oil 30 years ago.
Alyeska began its overhaul in 2004 with the goal of finishing in two years on a $250 million budget. The project remains incomplete and costs have risen to more than $400 million.
Chuck Hamel, a Virginia resident and longtime Alyeska critic, last month exposed problems with power failures, welding records and other issues in a letter to congressmen.
Hamel said the pipeline modernization project "is in total disarray."
That viewpoint is disputed by Alyeska as well as the commissioner of the Alaska Department of Natural Resources, Tom Irwin.
Pump Station 9, south of Delta Junction, is the only station where installation of new pumps, motors and controls is complete.
Alyeska began using the new equipment to pump oil in early February. Company executives have told regulators the revamped station generally has run smoothly and reliably. The company intends to mothball the old pumps next month.
However, left unchecked, it's feared that the vibration glitch could someday cause metal fatigue and ruptures in steel piping.
The vibration is not in the main 48-inch pipe that crosses Alaska from Prudhoe Bay south to the tanker port at Valdez. Rather, the vibration is in new piping that runs into and out of huge modules housing the pumps.
As a test to try to stop the shakes, Alyeska built rough ground supports underneath the pipes using wood blocks.
"That's a temporary fix just to try to take the vibration out," said Jerry Brossia, an official at the Joint Pipeline Office, an Anchorage umbrella agency for federal and state regulators who oversee Alaska pipelines.
Brossia and Alyeska spokesman Heatwole said the cribbing will stay in place until experts can figure out a permanent cure for the vibration, believed to be caused by oil rushing through elbows and turns in the piping.
Alyeska has hired an outside expert, structural engineer Jim Loftis of Fairbanks, to help devise a solution.
The U.S. Department of Transportation, which regulates pipelines, also has enlisted experts from the Oak Ridge National Laboratory in Tennessee, Brossia said.
Cribbing often is used to support piping in preparation for repairs or other operations, Heatwole said. After a powerful Interior earthquake in 2002, Alyeska put railroad ties underneath the pipeline for stability pending damage repairs.
According to Heatwole, the pump station and its pipes are safe to operate with or without the cribbing, which Alyeska could remove before winter.
"We're on a pretty fast track to get this taken care of," he said.
Four companies own Alyeska and the pipeline. BP has a 47 percent share, Conoco Phillips owns 28 percent, Exxon Mobil owns 20 percent, and Chevron and Koch Industries owns the rest.
Information from: Anchorage Daily News, www.adn.com