ALYESKA PIPE REPLACEMENT PROGRAM ADVANCES

Alyeska Pipeline Service Co. has completed a critical first phase of the Atigun pipe replacement project. The company set stopple plugs on the trans-Alaska crude oil pipeline, enabling North Slope oil to flow through bypass lines in preparation for the tie-in of 8 1/2 miles of new line. The portion of pipe being replaced lies in the Atigun floodplain, 160 miles south of Prudhoe Bay, where nearly 50% of the pipeline's corrosion has occurred. The stopple procedure, originally estimated to

Aug. 26, 1991

2 min read

Alyeska Pipeline Service Co. has completed a critical first phase of the Atigun pipe replacement project.

The company set stopple plugs on the trans-Alaska crude oil pipeline, enabling North Slope oil to flow through bypass lines in preparation for the tie-in of 8 1/2 miles of new line. The portion of pipe being replaced lies in the Atigun floodplain, 160 miles south of Prudhoe Bay, where nearly 50% of the pipeline's corrosion has occurred.

The stopple procedure, originally estimated to require a 2-4 hr slowdown of oil delivered to the pipeline, was completed in 1 hr 48 min.

Alyeska reduced pipeline flow to 25% of nomination, or about 487,000 b/d, while it set the stopples, resulting in a total production interruption of 271,673 bbl. A second slowdown is scheduled Aug. 29, when the new section of line will be placed in operation.

Other phases of the Atigun project have included manufacture of replacement pipe in Italy, pipe coating in Saudi Arabia using advanced corrosion protection techniques, shipment of the pipe to Valdez, Alas., and manufacture of the eight bypass stopples and related equipment. The new 8 1/2 miles of pipe was placed in the ground last February and March.

Alyeska has extensively tested the 48 in. replacement pipe, the 36 in. bypass line, stopples, and associated piping.

The project is part of Alyeska's mainline corrosion maintenance program.

The company is engineering a similar pipe replacement project at Chandalar, several miles south of Atigun. It plans to replace about 2 miles of pipe at Chandalar, the other section of the line where corrosion has occurred most frequently.

Alyeska will spend about $100 million on the Atigun pipe replacement project.

It is the largest single construction project on the line since it began operating in 1977.