(Corrects headline and paragraphs 1 and 5 after SoCalGas says completes tests on most wells, not all wells)
Oct 19 (Reuters) - Southern California Gas said on Wednesday it completed safety review tests at most of its wells at the Aliso Canyon natural gas storage facility in Los Angeles, which shut in October 2015 following a massive methane leak that was not plugged until February.
The utility did not say when it would be ready to seek state regulatory approval to inject gas into the giant field. It said it would make the request once it "has met all of the requirements" of the state's comprehensive safety review, but did not say what steps were left in that review.
Under state law, SoCalGas cannot inject fuel into the field 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.
SoCalGas is owned by California energy company Sempra Energy . Aliso Canyon is the biggest of its four storage fields. It supplies gas to homes and businesses in Southern California, including power plants and refineries.
The utility said 27 wells at the facility have passed all of the DOGGR tests with most of the remaining wells either temporarily or permanently shut in.
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 could not start injecting gas into Aliso Canyon until some time in November at the earliest.
In addition to DOGGR, the California Public Utilities Commission must also determine the field is safe to operate.
The state required SoCalGas to keep 15 billion cubic feet of gas in the 86-bcf facility to minimize the risk of gas shortages that could result in electricity outages.
The PUC in late September reduced the required minimum withdrawal capability SoCalGas must maintain from 420 million cubic feet per day to 207 mmcfd.
Separately, SoCalGas also said it replaced the inner tubing of all of the DOGGR approved wells, adding more than 40 miles of new steel piping.
In accordance with new regulations and state laws, withdrawal and injection of gas now will occur only through the newly installed inner tubing, the company said.
The casing around the inner tubing provides a secondary layer of protection against potential leaks. A federal task force this week called for a two-pipe system at all U.S. facilities. (Reporting by Scott DiSavino; Editing by Chizu Nomiyama and David Gregorio)