2 Spills Later, Shell to Replace Pipeline

Wednesday, August 16, 2017 @ 02:08 PM gHale


Shell Oil Co. is replacing more than 12 miles of a pipeline that carries crude petroleum from Central Valley, CA, oil fields to Bay Area refineries after an investigation into two ruptures in eastern Alameda County in 2015 and 2016.

The move follows a series of strong recommendations from the Office of the State Fire Marshal’s Pipeline Safety Division, a division of Cal Fire that oversees 6,500 miles of pipelines — the first time the agency has pushed for a pipeline replacement.

RELATED STORIES
Giving Pipeline Security a Boost
Robots Give a View of Pipelines
Exxon Settles AR Pipeline Leak Case
Santa Barbara Oil Spill Settlement

The ruptures took place on Shell’s 177-mile-long San Pablo Bay Pipeline, which runs up the west side of the San Joaquin Valley from Coalinga, across the southwestern edge of the Delta, and through the hills of eastern Alameda and Contra Costa counties to the company’s Martinez refinery.

The spills occurred between Altamont Pass and Tracy in September 2015 and May 2016.

Investigators found both ended up caused by “fatigue cracks” that grew as pressure on the underground line fluctuated to deal with different grades of oil.

The two ruptures spilled 60,000 gallons on grassland near Interstate 580 and resulted in more than $6 million in damage, emergency response and cleanup costs.

Oil from the first spill seeped 10 feet into the ground. Crude from the second incident was discovered as much as 20 feet beneath the surface, according to the Central Valley Regional Water Quality Control Board. The water agency oversaw the cleanups, which involved removing nearly 16,000 tons of contaminated soil and dumping it in an Altamont Pass landfill.

After completing an investigation into the 2016 spill, the fire marshal’s office placed the pipeline on its list of higher-risk lines, requiring Shell to conduct more frequent inspections.

Inspection Before Leak
Shell had inspected the failed sections of pipeline just months before they broke. The state last inspected the pipeline in 2012.

The fire marshal is calling on the company to review all its California pipelines that switch between different pressure levels to see if they need more frequent inspections. The state agency also wants to know whether the company can reduce the practice, known as “pressure cycling.”

The agency’s pipeline division also says it will review Shell’s pipeline integrity management program this fall.

Documents obtained by KQED give a vivid picture of how the second pipeline spill unfolded.

In the second pipeline incident, just after midnight on May 20, 2016, Shell’s pipeline control center in Houston, Texas, detected a drop in operating pressure on the pipeline near West Patterson Pass Road and Interstate 580. At the time, it was pumping more than 6,000 barrels of heavy crude per hour, state officials said. The company says it immediately shut down the line.

Two hours later the company notified the Governor’s Office of Emergency Services, several local agencies were called in to respond, and a cleanup effort began that would last for months.

The 24-inch pipeline released 500 barrels of oil from a break that measured 45 by 4.5 inches, according to state investigators.

As it did for the September 2015 break, Shell hired the risk management firm, Det Norske Veritas (DNV), to investigate the May 2016 spill.

‘Fatigue Crack’
DNV and Shell say the rupture was due to a “fatigue crack” that grew over time. The oil company also says that smart pig, or in-line, tests conducted on the pipeline before the break were incorrectly reported to Shell officials.

Shell said incorrect information led them to increase pressure on the line three days before it ruptured.

Like the first break, DNV said small pits of corrosion, along with the line’s frequent changes in pressure due to the different grades of oil it carries, contributed to the rupture. The firm added the crack could have developed when the pipe was transported to the West Coast 35 years ago.

Shell just began the process of replacing three sections of pipeline totaling 12.5 miles, company spokesman Fisher said. Each of those sections — one near Tracy, one near the Stanislaus-Merced county line, and one near Coalinga — involves pipeline that was manufactured in 1982 and then stored outside for six years before being shipped to California and installed as part of an existing pipeline.

“Shell is choosing to replace the 1982 Columbia pipe sections with newly fabricated pipe out of an abundance of caution, despite the existing pipeline having been repaired and passing subsequent hydrotests,” Fisher said.

Shell is not disclosing the cost of the project.



Leave a Reply

You must be logged in to post a comment.