Trans-Alaska oil pipeline plans bullet-hole drill

Involves field testing clamp designed to quickly seal high-pressure leak

 

BY WESLEY LOY FOR GREENING OF OIL 

Alyeska Pipeline Service Co. is planning a field exercise this year to test a hydraulically powered clamp designed to stop oil squirting out of the trans-Alaska oil pipeline through a bullet hole.

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The drill is part of a series of oil spill response exercises the Anchorage-based operator of the 800-mile line aims to conduct this year and in 2011.

The bullet-hole exercise is planned for Milepost 438 of the pipeline at the Chatanika River, say documents Alyeska recently filed with the Alaska Department of Environmental Conservation.

A test piece of 48-inch mainline pipe will be placed at the scene and pressurized with water to simulate a high-pressure oil spray through a bullet hole, an exercise description says. Equipment including Alyeska’s HC 320 hydraulic clamp will be dispatched from the company’s Fairbanks Response Base.

A simulated 60-barrel release is expected over the course of the planned 12-hour exercise, and Alyeska and regulators will time and evaluate all the activities, the exercise description says.

The drill is scheduled for the third quarter of this year, though Alyeska spokesman Matt Carle said it could come sooner to avoid conflicts with planned summer maintenance shutdowns along the pipeline.

The HC 320 clamp already has been field tested twice, Carle said.

“We know it works,” he said, adding the next exercise will give Alyeska a chance to test its equipment and workers in front of regulators.

The pipeline shooter

Alyeska developed the HC 320 clamp after a man shot the pipeline with a high-powered rifle in October 2001 near the Livengood community about 80 miles north of Fairbanks. The bullet pierced the steel pipe and insulating jacket, unleashing a jet of oil into nearby woods.

An estimated 285,600 gallons of oil spilled, and it took responders 36 hours to relieve pressure in the line and seal the bullet hole amid worry the fine oil mist in the air might explode. Alyeska drew both praise and criticism for its performance.

The drunken shooter, Daniel Carson Lewis of Livengood, was convicted on a variety of charges and drew a multiyear prison sentence.

With the help of some Fairbanks contractors, Alyeska worked to develop a lighter and more maneuverable clamp better able to deal with high-pressure leaks than the crane-lifted hydraulic clamp used in the 2001 incident.

How it works

Petroleum News, in October 2007, published a story that described the HC 320 clamp.

“The concept for the clamp was based on large excavators used in the logging industry,” the story said. “Those machines have an arm attached that is used to pick up huge logs.”

An Alyeska emergency preparedness manager said the HC 320 can quickly latch onto the pipe, covering a hole. The clamp under certain conditions can stay attached as a temporary repair, allowing the pipeline to re-start. Alyeska has more than one of these clamps, Carle said, but he declined for security reasons to specify how many.

Links of interest

Alyeska Pipeline Service Co.

1-29-2006 Petroleum News: Web posting calls for attacks on pipeline

5-22-2005 Petroleum News: Plugging bullet holes quicker

3-3-2002 Petroleum News: Response to bullet hole in pipeline called success

2-17-2002 Petroleum News: Shooting led to event that moved pipeline

10-28-2001 Petroleum News: Alaska State Troopers find additional bullet strikes in pipeline

10-21-2001 Petroleum News: Pipeline security underscored by response to Livengood spill

10-14-2001 Petroleum News: Trans-Alaska pipeline, shut down by bullet hole

Editor’s note: This article was originally published in Petroleum News.


Contact Wesley Loy at wloy@petroleumnews.com