The 800-mile Trans-Alaska Pipeline, which continues to leak oil while running at reduced capacity, will be shut down again this weekend to install a bypass to a faulty pipe.
The leaking steel pipe, encased in concrete, leads to the basement of the booster pump building at Pump Station 1, where corrosion monitoring efforts have been the focus of attention.
The hole in the line is believed to be caused by corrosion, although pipeline operator Alyeska Pipeline Service Co. says it cannot confirm the cause until the faulty pipe is excavated.
A bypass pipe is being fabricated in Fairbanks and will be flown to the North Slope when ready for assembly and installation. The buried line that is leaking (380 miles of the pipeline is buried) was scheduled for a replacement project that was to have begun this year.
The leak was discovered at 8:16 a.m. local time Saturday (Jan. 8), as oil flowed into the small space between the pipe and the concrete, then through the wall of the building into the basement.
The pipeline was shut down about 30 minutes later, and oil-recovery operations began several hours later. An 800-gallon containment tank is being used to capture the oil.
The shutdown continued until Tuesday afternoon—the second-longest shutdown since the pipeline opened in 1977.
Federal and state regulators allowed the pipeline to reopen at about two-thirds’ capacity (about 400,000 barrels per day), although the leak continues to release 1.8 gallons of oil each minute, according to the Environmental Protection Agency.
Alyeska had expressed concern that a prolonged shutdown during the winter could cause additional wax and ice buildup in the lines, leading to additional damage.
Corrosion and Coatings
Pump Station 1 at Prudhoe Bay raises the pressure of the oil to get it to Pump Station 3, at 1,383 feet above sea level.
In the past decade, federal regulators have required Alyeska to improve its corrosion detection at Pump Station 1 and replace an aging line that carried most of the oil from the North Slope to the pump station, according to the Anchorage Daily News. That line was replaced in December, according to BP.
Alyeska is a consortium, with about 46% owned by BP, about 28% by ConocoPhillips, about 20% by Exxon Mobil, about 3% by Koch Alaska Pipeline Co. LLC, and about 1% by Unocal Pipeline Co.
Protective coatings are used throughout the pipeline project: in superstructures for the berths at the Valdez Marine Terminal, in the concrete-ballasted buried pipeline, and in the Valdez terminal storage tanks.
Corrosion prevention and control is a critical focus on pipeline operation and maintenance, Alyeska says.
Corrosion monitoring includes about 800 coupons along the 380 miles of buried pipeline.
This week, Rep. Edward Markey (D-MA), the ranking Democrat on the U.S. House Natural Resources Committee, sent a letter to Alyeska, asking what caused the leak and whether the decision to restart has created new spill risks, the Anchorage Daily News reported.
The letter noted that Alyeska “testified to Congress in 2007 that accelerated corrosion was not a threat for the 800-mile line,” the newspaper reported. “The company also testified that it had added new corrosion monitoring locations at Pump Station 1,” Markey wrote.
“’It would appear those new monitoring locations were insufficient,’” Markey added, according to the newspaper. He requested a response by Tuesday (Jan. 18).