Oct 5 (Reuters) - California state regulators have reduced the required amount of natural gas that must be available for withdrawal from the Aliso Canyon storage facility, which Southern California Gas said could hasten the return to service of the field that was shut after a massive methane leak in 2015.
SoCalGas, a unit of California energy company Sempra Energy , shut its biggest storage field in October 2015, due to a massive methane leak that displaced thousands of residents and forced entire neighborhoods to be evacuated. The leak was not plugged until February.
The state required the utility to keep 15 billion cubic feet of gas in the 86-bcf facility, with gas to be withdrawn only in an emergency to guard against blackouts and prevent the region's power plants from running out of fuel.
There were no blackouts over the latest summer, in part because power consumers reduced usage and actual temperatures during a heat wave in June were not as hot as forecast.
With the weather moderating, the California Public Utilities Commission (PUC) last week reduced the required minimum withdrawal capability SoCalGas must maintain at Aliso Canyon from 420 million cubic feet per day to 207 mmcfd.
Before the leak, Aliso Canyon was able to deliver almost 1.9 bcfd, according to federal data.
"The reduction in required withdrawal capacity means fewer wells must be kept ready for withdrawal, and may assist in more quickly completing the state-mandated comprehensive safety review and safely resume injection operations at the facility," Melissa Bailey, a spokeswoman at SoCalGas, said.
Under state law, SoCalGas cannot inject gas into Aliso Canyon until the California Division of Oil, Gas and Geothermal Resources (DOGGR) approves the company's testing of the 114 wells at the facility to ensure their safety.
In addition to DOGGR, the PUC must also determine the field is safe to operate.
According to its latest report on Sept. 16, SoCalGas said 23 wells passed all safety tests, 15 awaited test results and 76 were temporarily out of operation.
All wells must either pass all tests or be taken out of service before DOGGR can call a public meeting. Since DOGGR must give the public 15 days notice before a meeting, SoCalGas would not be able to start injecting gas into the field until late October at the earliest.
Bailey could not say when SoCalGas would complete the well tests, noting "Our focus is on safely completing the review process...not to meet a specific date."
Reporting by Scott DiSavino; Editing by David Gregorio