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Valdez terminal piping gets close look Inspectors look for corrosion in overwater lines that deliver huge volumes of Alaska North Slope crude oil to berthed tankers Wesley Loy For Petroleum News
The operator of the tanker terminal at Valdez is conducting corrosion inspections on oil pipes that pose a potentially high spill risk.
The piping is mounted on causeways, which lead to the berths where tankers load. Because the pipes are suspended above water, and carry huge volumes of crude oil to the ships, their integrity is vital.
Alyeska Pipeline Service Co. operates the 800-mile trans-Alaska pipeline and the Valdez tanker terminal.
Three years ago, Alyeska launched a special project known as Z683 to “look at vulnerable areas for external corrosion” at the terminal, company spokeswoman Michelle Egan told Petroleum News.
Part of the project involves inspecting the overwater piping on berths 4 and 5, the two active berths for loading tankers.
Focus on welds Crews are focusing on inspecting girth welds on berth piping, Egan said.
The crews “have found a few places where the pipe needed coating repairs, and are working to remediate those areas,” she said.
Crews must remove thermal insulation to get a look at the welds. As of Sept. 10, crews had exposed, inspected, repaired if necessary, and reinsulated 34 girth welds, Egan said.
The inspections will continue this fall and in 2014 as part of Alyeska’s ongoing integrity management process, she said.
As in most any aging industrial facility, corrosion is a constant worry at the Valdez terminal, a sprawling complex of enormous oil storage tanks, pipes and piers. North Slope crude has been flowing into the terminal since 1977.
Dr. Rust Potential corrosion issues with overwater piping came to light in late 2012 after a consultant, Dr. Rust Inc., of Cape Canaveral, Fla., conducted a corrosion survey of the terminal for the Prince William Sound Regional Citizens’ Advisory Council.
The council is a congressionally mandated organization that monitors the terminal and associated tanker traffic.
The consultant generally recommended improved inspections of the terminal’s more inaccessible piping.
Large-diameter pipes extending over water were a particular focus for the consultant. His report included Alyeska-supplied photos of severe corrosion on piping on berth 4. The corrosion was found after insulation was removed.
The council said its staff on Aug. 2 accompanied Alyeska personnel on a visit to the berth 4 causeway to observe the inspection activity.
“Alyeska indicated and staff observed that the girth welds already inspected, whether coated or not, had at worst only superficial corrosion that was easily cleaned, recoated, and reinsulated,” the council said in a recent status report. “No corrosion of the extent that was found during the summer of 2012 on the Berth 4 crude oil riser pipes has been found during this year’s inspection activities.”
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