Maintenance shutdowns are choreographed events

Oil normally flows through the Trans Alaska Pipeline System (TAPS) 24 hours a day, seven days a week, with no time off for holidays. But the flow must occasionally stop for pipeline maintenance and upgrades.

The pipeline is a continuous system that runs from Prudhoe Bay to Valdez and pipeline managers cannot turn off certain sections without stopping oil flow everywhere.

"These shutdowns may seem routine,” said Wyche Ford, Alyeska manager of projects, "but they require a tremendous amount of advance planning and coordination to minimize shutdown time.”

TAPS managers also coordinate shutdowns with North Slope producers and their maintenance projects to minimize disruption to oil production and the flow of the Alaska’s most important economic resource.

"You have to ensure people are properly trained, equipment is tested and that procedures have been reviewed before you start the actual work. All of this pre-shutdown work provides assurance that the job will be completed successfully and efficiently," said Holly Schoenborn,
2004 Shutdown Coordinator.

Alyeska conducts line-wide shutdowns almost every year to continually renew, maintain and improve the pipeline and insure its integrity and longevity. There are two scheduled shutdowns this summer. One was successfully completed on July 10 and 11 and a second shutdown is scheduled for August 16 and 17.

Crews used the July shutdown to work on dozens of projects along the entire 800-mile-long pipeline. A team of more than 100 workers replaced two pig-launching valves at Pump Station 4. Pigs are devices that are inserted into the pipeline to do everything from inspections to maintenance and cleaning functions. Other crews set limit switches on valves at 10 different sites along the pipeline. Limit switches assure that valves open and close properly, shutting off or resuming the flow of oil upon command. And crews replaced aging natural gas distribution valves at Pump Station 3. Pump stations 1, 3 and 4 are powered by natural gas.

The August shutdown will allow work associated with Alyeska’s pipeline reconfiguration. This project is one of the biggest pipeline investments since construction. It will install new, electrically driven oil pumps at Pump Stations 1, 3, 4 and 9 and modernize and automate many pipeline control systems. The project goal is to increase TAPS managers’ ability to accommodate changing pipeline throughput demands from North Slope producers. It should also extend TAPS’ economic life through increased efficiencies, while maintaining safety, integrity and environmental performance standards. The project is scheduled for completion at the end of 2005.

Alyeska uses storage tanks at the Valdez Marine Terminal to accommodate tanker schedules and variations in pipeline throughput during a planned shutdown. Shipping vessels maintained their normal loading schedules during the July shutdown and the same is expected for the August shutdown.