Fix of pipeline fitting weep completed

Repair of a slow weeping of crude oil from a fitting on the trans-Alaska oil pipeline at Pump Station 10, discovered in late May, has been completed.

The Alaska Department of Environmental Conservation, Division of Spill Prevention and Response, said Nov. 5 that a 60-inch sleeve was fabricated for installation over the isolation fitting, has been welded in place and “is now providing full pressure containment of the isolation fitting,” providing full source control.

Pump Station 10, along the Richardson Highway at milepost 219, trans-Alaska oil pipeline milepost 585.91, has been out of service since 1998 but is in use to support operations along the line.

Alyeska Pipeline Service Co. employees discovered the spill on May 29. It had an initial weep rate of about one drip per second and oil had accumulated within the tar membrane/packing material that covered the coupling. Oil dripped from the fitting once the soil surrounding the pipe was removed. No active weeping was observed when the tar membrane and tar were removed from the pipe, but small dampened areas started to appear at a later time on the coupling surface, indicating weeping from the joint was still active.

The release was found during excavations to investigate a corrosion inspection anomaly in a separate location along the main line and Alyeska Pipeline Service Co. personnel then discovered discolored gravel at the leaking isolation fitting joint.

Contaminated gravel at the site was removed to the maximum extent practicable, DEC said. The department approved backfill of the excavation Oct. 28.

- Petroleum News