Alyeska questions ‘stray metal’ list

Federal regulators propose several ‘corrective measures’ to prevent another wall failure along 800-mile trans-Alaska pipeline

Wesley Loy

For Petroleum News

Alyeska Pipeline Service Co. is questioning the need for extensive “corrective measures” federal regulators are proposing for the trans-Alaska oil pipeline.

Alyeska is the Anchorage-based company that runs the 800-mile pipeline on behalf of owners including BP, ConocoPhillips and ExxonMobil.

The U.S. Pipeline and Hazardous Materials Safety Administration recently issued Alyeska a “notice of proposed safety order” with a list of corrective actions to address an unusual event along the pipeline.

The event involved the Sept. 8, 2013, discovery of a stray piece of metal lodged inside a valve at the Valdez Marine Terminal at the end of the pipeline.

Alyeska was able to trace the piece to a failed maintenance job in August 2012 near milepost 385, about 70 miles pipeline north of Fairbanks.

The job involved welding a domelike “encapsulation” over an unused pipeline air vent, and filling it with epoxy. The encapsulation was welded onto the pipeline at the 12 o’clock position.

The problem was that as the epoxy cured, incredible pressure built up inside the encapsulation — enough to punch out the pipeline wall underneath.

The round piece, 10 inches in diameter with a stem attached, felt into the pipeline and rode in the oil stream to Valdez.

Concerns about other caps

The federal pipeline regulators have raised concerns that similar problems might be lurking at some 90 other epoxy-filled encapsulations Alyeska installed over pipeline vents and drains between 2010 and 2013.

The purpose of the encapsulations was to safeguard against potential spills.

PHMSA, in its notice, proposed several corrective measures and deadlines, including increased encapsulation monitoring, ultrasonic and other testing, and pressure relief.

Alyeska has said it’s operating the pipeline with “full confidence” in its integrity.

In an April 11 letter responding to PHMSA, Alyeska said pipeline pigging and radiographic exams showed that no other encapsulations have metal loss.

Alyeska took immediate steps to repair the failed vent encapsulation at MP 385, and “has taken numerous investigative and corrective actions in response to the incident,” said the letter, signed by company President Tom Barrett.

The letter said Alyeska “has questions about the justification and scope of certain of the proposed corrective measures and the potential magnitude of actions that would be necessary to implement the corrective measures as proposed, and within the apparent expected timeframes.”

Expert contractor retained

This likely will involve a sit-down between Alyeska and PHMSA regulators, possibly at the agency’s Denver office on May 8.

In its letter, Alyeska said work to further address concerns raised in the proposed safety order is planned for the upcoming summer along the pipeline, which is partly buried and partly above ground.

“Alyeska is conducting engineering design for the construction packages needed for the 2014 encapsulation inspection digs,” the letter said.

The company has contracted with Stress Engineering Services for “technical lab testing and analysis relating to epoxy and structural questions,” the letter said. “They have begun their analysis and we expect their work to help inform decisions on any further encapsulation work and/or monitoring. The final scope of work includes the rigorous testing designed to answer the concerns outlined in the proposed safety order.”

In light of the work the contractor is doing, Alyeska said it “requests further discussions concerning PHMSA’s assumptions and expectations as to necessity, scope and schedule” for a proposed requirement to test pressure inside the encapsulations, and relieve pressure if necessary.