News: Wall Street Journal, February 11, 2002
Shift by the Trans-Alaska Pipeline Went Undetected for Two Months
By JIM CARLTON
Staff Reporter of THE WALL STREET JOURNAL
A mile and a half portion of the Trans-Alaska Pipeline slipped as much as 14 inches off its anchorings following a shooting puncture last fall, and it went undetected for two months.
Officials of the Alyeska Pipeline Service Co., which operates the 800-mile pipeline, recently notified government authorities of the incident after it was discovered in early January. Although Alyeska officials say the pipeline was quickly put back into place with no major damage, both government officials and environmentalists are questioning why it took so long to discover the mishap and whether a disastrous spill could have happened as a result.
Officials of the Joint Pipeline Office, a state-federal agency in Alaska, say they have launched an investigation into the matter.
"This raises serious questions about Alyeska's ability to operate the pipeline safely," said Richard Fineberg, an environmental consultant in Fairbanks, Alaska, and frequent critic of Alyeska.
Officials of Alyeska, which is owned by a consortium that includes Exxon Mobil Corp., Phillips Petroleum Co. and BP PLC, say the overall integrity of the pipeline remained intact and that it worked as designed in response to a great shock.
They say the pipe movement was detected Jan. 4 by a crew conducting a routine quarterly check of an area deep in the Alaskan interior, some 200 miles north of Fairbanks. There they discovered that the pipeline had shifted as much as 14 inches over the mile and a half stretch, by sliding off fittings designed to anchor it in place.
Alyeska's critics say the pipeline was left more vulnerable to an earthquake or another incident of human error and that both the environment and national security could have suffered as a result. The Alaska pipeline transports roughly one-fifth of America's domestic crude-oil supplies.
Alyeska officials say they are looking into ways they can detect such mishaps more promptly, such as by more frequent checks.
Write to Jim Carlton at email@example.com
Fairbanks News Miner
February 10, 2002
Shift in pipeline blamed on bullet hole repair
By The Associated Press
ANCHORAGE--The trans-Alaska oil pipeline shifted more than a foot toward
Prudhoe Bay in October at a site south of the Brooks Range after Alyeska
Pipeline Service Co. took steps to stop the flow from a bullet hole.
Company officials say they have determined that the pipeline shift discovered in
January occurred after the flow of oil in the line was reversed. The high rate of
back flow tripped a check valve clapper, a dome-shape plug that swings down
like a door on a hinge, and the pressure pushed the pipeline north.
The shift did not damage the pipeline and it remained operational. Anchor
assemblies along aboveground portions of the pipeline are designed to absorb
movement vertically, laterally and longitudinally.
Alyeska discovered the pipeline shift Jan. 4 during quarterly ground surveillance,
spokesman Mike Heatwole said Friday.
"The amount of movement is pretty difficult to see from the air," Heatwole said.
The shift tripped seven anchors along a mile-and-a-half section of the line.
Repairs to the anchors were completed six days later and crews used hydraulic
jacks to put the pipeline back in place.
Company officials at the time said they thought the pipeline had shifted one day
before it was discovered. But engineers since then determined that the shift
occurred as workers prepared to plug a hole from a bullet fired Oct. 4.
An estimated 285,600 gallons of oil spewed onto the ground 75 miles north of
Fairbanks before Alyeska plugged the line three days later.
The shift came about as oil flowed north and hit the clapper of Check Valve 50,
located south of Pump Station 5 between Mile 275 and 280 of the pipeline.
Check valves operate one-way and prevent reverse flow of oil. Check valves are
designed to be held open by flowing oil and to close automatically when oil flow
stops or is reversed.
As part of the bullet hole repair, Alyeska relieved pressure on the line. The
clapper on Check Valve 50 was cranked to the "up" position so that oil could be
pumped around a remote gate valve to a relief tank at Pump Station 5.
The day after the shooting, workers opened four relief valves to create a path for
the oil to the relief tank. However, during the procedure, when crude oil flowed
north from Gobbler's Knob, a landmark higher than the check valve, the flow rate
exceeded 1.2 million barrels a day at Check Valve 50.
The rate was so high, it sheared an actuator shear key, part of the assembly
that holds the clapper in place. That caused the clapper from Check Valve 50 to
drop, and the pressure shifted the pipeline 13 inches.
"That flow rate is what our engineers determined is what caused the clapper to
come down," Heatwole said.
The check valve functioned properly, he said.
"From our perspective, all the pieces worked as they were supposed to,"
The pipeline has moved on its supports before. In April 2000 a vapor pocket in
the pipeline collapsed at Atigun Pass in the Brooks Range, causing a wave of
pressure that moved the pipeline.
Daniel Carson Lewis, 37, faces state felony charges of criminal mischief,
assault and drunken driving as well as misdemeanor charges of oil pollution and
weapons misconduct in connection with the pipeline shooting. He is accused of
firing at the pipeline multiple times with a .338-caliber rifle.
Cleanup crews continue to work at the site and expect to have all contaminated
material picked up in about a month, Heatwole said. They have already removed
an estimated 1,300 yards of contaminated trees, vegetative material and soil for
storage at Moose Creek south of Fairbanks.
More than 175,000 gallons of spilled oil has been reinjected into the pipeline.