Coatings Industry News

Main News Page

Corrosion Blamed for 2015 Gas Leak

Friday, May 24, 2019

Comment | More

A new independent report has revealed microbial corrosion as the culprit behind a natural gas leak in South California, an incident that released 109,000 metric tons of methane over a five-month period between 2015 and 2016.

The corrosion occurred on well equipment, according to Ars Technica. Southern California Gas Co. (SoCalGas) has been blamed for failing to follow up with equipment inspections, though the company was aware of 60 leaks that had occurred since the 1970s. According to the same report, this was the largest methane leak in U.S. history.

Gas Leak Incident

The Aliso Canyon leak, said to have been the worst natural gas leak in U.S. history in terms of environmental impact, was discovered at a facility owned by SoCalGas in October 2015. The exact location of the leak was not found until late December that year, and the leak was not stopped until February 2016; more than 8,000 households were evacuated during that time, according to Southern California Public Radio.

During the crisis, California Gov. Jerry Brown declared a state of emergency, ordering withdrawals of gas from Aliso Canyon for transportation and storage elsewhere. The Aliso Canyon facility uses injection wells to inject natural gas into natural underground storage areas.

Scott L, CC BY-SA 2.0, via Wikimedia Commons

The Aliso Canyon leak, said to have been the worst natural gas leak in U.S. history in terms of environmental impact, was discovered at a facility owned by the Southern California Gas Co. in October 2015.

According to a report sent by Blade Energy Partners to the California Public Utilities Commission, the consulting firm found a full fracture of the 7-inch casing, as well as a 19-inch axial split running down the lower section of the split casing. Outer-diameter corrosion surrounding the split, the report notes, indicates that the axial split was “associated with wall thinning due to corrosion.”

The report also cited examples of mechanical damage on the casing, including slip marks, tool marks and tong marks.

The well that was the source of the leak was built in 1953 and, according to reports, in 1979, its emergency shut-off valves were removed because they were failing. They were not required to be replaced, however.

Latest Report

Commissioned three years ago, the latest report, from Blade, was issued to find the root cause of the leak, which was connected to a 7-inch outer well casing that had corroded due to groundwater microbes.

“SoCalGas did not conduct detailed follow-up inspections or analyses after previous leaks,” the company writes in its report. “Blade identified more than 60 casing leaks at Aliso Canyon before the October 2015 incident going back to the 1970s, but no failure investigations were conducted by SoCalGas.”

The report also indicates that SoCalGas lacked risk assessment options geared toward well integrity management, and also lacked “systematic practices of external corrosion protection," along with a continuous pressure monitoring system for well surveillance.

SoCalGas noted in its own statement that the report did not find any transgressions against well or safety rules at the time.

"The release of this report marks an important milestone in helping the region and California move forward from the Aliso Canyon natural gas leak,” SoCalGas wrote. “The leak was an industry-changing event resulting in the development and implementation of enhanced safety regulations and practices.

"Today Aliso Canyon is safe to operate and Blade's report indicates the industry leading safety enhancements and new regulations put in place after the leak should prevent this type of incident from occurring again.

"While we are still reviewing the report released today, we appreciate Blade acknowledging SoCalGas' full cooperation and support.”

Currently, there are more than 36,000 people suing SoCalGas over the five-month incident.


Tagged categories: Corrosion; NA; North America; Oil and Gas; Program/Project Management

Comment Join the Conversation:

Sign in to our community to add your comments.

Axxiom Manufacturing

KTA-Tator, Inc. - Corporate Office

HoldTight Solutions Inc.


Western Technology Inc.



Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL

The Technology Publishing Network

PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
MORE:      About   |   Privacy Policy   |   Terms & Conditions   |   Support   |   Site Map   |   Search   |   Contact Us