The trans-Alaska pipeline will shut down starting Friday for 36 hours of scheduled summer maintenance. Meantime, pipeline operator Alyeska Pipeline Service Co. is assessing the best way to fix a "weeping joint" discovered along an underground section of the line.
The "weep" at a pump station between Delta Junction and Glennallen -- with crude leaking a rate of 1 teaspoon each day -- is contained and under constant monitoring, said Michelle Egan, corporate communications director for Alyeska. It's falling into a drip pan when an employee isn't wiping off accumulated oil with a rag, she said.
The leak will be fixed after the shutdown, she said. Maintenance conducted during a shutdown involves multiple organizations and projects, with planning taking place over several months, she said.
"It's more prudent for us to go through the work we have planned," she said. "There's no reason this has to be addressed in this shutdown."
The leak appears to have been caused by possibly degraded material that separates the steel pipe from a steel fitting. More investigation will determine the cause, said Egan.
"We have been working on engineering the solution, and we're looking at a few different options," said Egan, including installing a sleeve to stop the leak.
The rate of the leak had initially been reported by state regulators as one drop per second, but that was because oil had collected within a packing material wrapping the joint. Once the material was removed, the leak was found to be much slower than originally suspected, said Egan.
The leak is not related to corrosion of the pipe, she said.
About half a million barrels of oil a day flow through the 800-mile pipeline, providing the primary source of state revenue. The Department of Environmental Conservation said last week it would work with Alyeska on a response to the leak.
Twenty-one other sections of the pipe with similar material might also be inspected, depending what caused the failure in the "weeping" section.
As for Friday's shutdown, crews will conduct work that includes testing valves along line to make sure they seal properly. Another focus will be replacing pig launcher valves at Pump Station 1 at Prudhoe Bay, the start of the line, that are associated with the pig devices that clean the pipe or test it for corrosion.
Other scheduled summer maintenance will include "a short-duration shutdown" of six to eight hours and another, longer shutdown Aug. 21-22.