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SoCalGas says Aliso Canyon gas leak now plugged

15 February 2016

The leak at Southern California’s Aliso Canyon gas storage site, which is estimated to have released almost 100,000 metric tonnes of methane into the atmosphere over the last four months, has now been temporarily plugged according to site owner Southern California Gas Co (SoCalGas). On February 11 the relief well intercepted the base of the leaking well and heavy fluids were pumped down to staunch the flow of gas.

The Aliso Canyon relief well - Image: SoCal Gas
The Aliso Canyon relief well - Image: SoCal Gas

"We have temporarily controlled the natural gas flow from the leaking well and begun the process of sealing the well and permanently stopping the leak", SoCalGas said in a statement.

Over the next few days cement will be injected into the base of the leaking well to permanently seal it, the company said. SoCalGas is also continuing preparations to drill a back-up relief well as a precautionary measure and will continue with this until the leak has been confirmed to have been plugged.

The California Division of Oil, Gas and Geothermal Resources (DOGGR) will officially announce the success of the operation when their tests confirm the leak has completely stopped.

The 11,300 residents in the nearby community of Porter Ranch who were relocated to hotels and other temporary accommodation because of the leak will then be given a week to return to their homes, the company said.

This major leak of methane has brought the state and country’s gas storage industry into close focus. In a report on February 12, the Los Angeles Daily News said that according to data from the Environmental Protection Agency, Aliso Canyon emitted 206,268 combined tons of natural gas, carbon dioxide and other pollutants in 2014, a year without any major leak incidents.

Other major polluting gas storage sites include Hattiesburg Gas Storage in Mississippi and Lake Gas Storage in Texas, which leak a far higher proportion of greenhouse gases into the atmosphere than other comparable facilities across the country, according to the Daily News.

The site at Aliso Canyon is a former oilfield that was abandoned in the 1950s and converted to a gas storage site in 1973. Not all the wells on the site were properly sealed and lack of investment in infrastructure here over the years replicates the wider situation across the USA.

Existing roads, bridges, ports, water systems, and other infrastructure need an estimated $1.6 trillion in upgrades, according to a 2010 report from the Department of Homeland Security, while the American Society of Civil Engineers (ASCE) says that infrastructure failures could cost the US $3.1 trillion by 2020.


On February 18, the California Division of Oil, Gas and Geothermal Resources (DOGGR) confirmed that the well that had been leaking at the Southern California Gas Co. (SoCalGas) Aliso Canyon storage facility has been permanently sealed and taken out of service.

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