By Austin Love
Council Project Manager
For the first time since the facility’s construction was completed in 1977, a majority of the large diameter crude oil piping at Alyeska’s Valdez Marine Terminal is undergoing a comprehensive inspection, both externally and internally. The inspections of these 36 and 48 inch diameter pipes began in 2016, and will be completed by the end of 2018.
Alyeska can use the data from these inspections to evaluate the current, complete condition of the large diameter piping used to move Alaska North Slope Crude onto tanker ships at the terminal.
A tremendous amount of work by Alyeska and their contractors is making these inspections possible:
- Concrete foundations had to be reinforced to accommodate loading stresses associated with the inspections;
- Piping inspection tool access and retrieval points had to be created at multiple locations;
- Sharp bends and large valves had to be removed from certain piping sections to allow for the passage of inspection equipment;
- The piping has to be cleaned of accumulated wax and debris after 40 years of use; and
- With the exception of a few necessary, planned pipeline shutdowns, most of this work was done while crude oil was still flowing through the pipeline and tank ships were still loading.
Alyeska has had to overcome a number of challenges in order to successfully complete the inspections:
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- Some of the piping is buried underground and in some cases encased in concrete, making access difficult if not practically impossible;
- Other sections of piping are relatively steep, creating a challenge to control the velocity of inspection tools; and
- Certain sections of piping could not be cleaned with traditional cleaning tools, but instead were cleaned with high pressure water jets.
New tech making the inspections possible
Before this expansive inspection work, the piping had been monitored and inspected to a relatively limited extent. Technological advancements have helped make this comprehensive inspection work feasible.
Traditionally, piping and pipelines, including the Trans Alaska Pipeline System, have been inspected with “free swimming” tools that are propelled by the flow of oil in the line. However, using oil to push an inspection tool along is not always feasible or practical. To address the propulsion shortcomings of traditional inspection tools, newer “self-propelled” piping inspection tools have been developed to inspect more challenging sections of piping. Alyeska used a self-propelled, robotic crawler tool for all of the inspections that took place at the terminal in 2016 and 2017; whereas in 2018, the inspection work will use a traditional “free swimming” inspection tool.
Alyeska’s 2016 and 2017 inspection results have shown that the crude oil piping at the Valdez Marine Terminal is in good working order, requiring no repairs. The Council will continue to track the progress and results through the rest of the project.
