Alyeska reports on pump station status

Out-of-service pump stations continue to be used for ancillary operations, maintenance; PS 7 used for heating oil and cold restart

ALAN BAILEY

Petroleum News

As part of the regulatory requirements for disconnecting some of the old pump stations along the trans-Alaska pipeline, Alyeska Pipeline Service Co., the pipeline operator, has filed its annual status reports for the redundant pump stations with the Regulatory Commission of Alaska. Essentially pump stations Nos. 2, 6, 7, 8, 10 and 12 have been isolated from use in pumping oil along the line.

In 2004 when starting work on the strategic reconfiguration project, a project to replace the original turbine-powered pumps that drove oil through the pipeline with electrically powered pumps, Alyeska asked the RCA for approval to take out of service several of the pump stations that were no longer needed, given the declining rate of oil flow through the line. The company was going to electrify pump stations Nos. 1, 3, 4 and 9, after which these would be the only pump stations in use.

At that time, pump stations Nos. 7 and 12 were still in active use. The other pump stations scheduled for decommissioning, while still connected to the pipeline, were no longer being operated.

The RCA approved the decommissioning, subject to Alyeska filing annual reports on the obsolete pump stations, as long as there are activities conducted at the facilities, Hence the latest status reports that Alyeska has filed - although the surplus pump stations have been isolated from the oil line, the facilities are used to some extent in support of ancillary operations and pipeline system maintenance.

With Alyeska facing a growing problem with the cooling of oil in the pipeline in the winter, as North Slope oil production drops and oil flow through the line slows, pump station No. 7 is now used in the winter for heating the oil in the line, one of the reports says. Moreover, pump stations Nos. 7 and 12 now have facilities to help with a cold restart of the line, as a contingency arrangement, should the line have to stop operating in the winter. As part of its arrangements for keeping the oil passing down the line sufficiently warm, Alyeska also cycles the oil at the active pump stations.

Pump station No. 6 is being used as an oil spill response base.

The report for pump station No. 10 says that early engineering for the removal of the facilities that remain at that pump station may start this year, with retirement of the facilities possible in 2018 and 2019. Alyeska has no firm plans for eventual removal of the other pump stations - removal of pump stations Nos. 2 and 6 would happen no sooner than 2018, and removal of pump station No. 8 no sooner than 2019, the reports say.