More than half of the storage wells at the closed Southern California Gas Co. (SoCalGas) Aliso Canyon underground natural gas facility in Los Angeles have been isolated for further assessment as to whether or not they should be permanently plugged, according to a report from the California Division of Oil, Gas and Geothermal Resources (DOGGR).
The information surfaces many months after a four-month-long storage well leak that wreaked havoc last winter and at a time the Sempra Energy gas-only utility had once targeted for restarting the 86 Bcf capacity, 3,600-acre storage field (see Daily GPI, April 8). The revelation also comes while SoCalGas and DOGGR are still in the midst of testing all 114 storage wells at Aliso Canyon, using a time-consuming two-stage process (see Daily GPI, March 29).
DOGGR's latest statistics indicate that 26 of the wells have passed all required tests, but another 66 wells have been temporarily isolated from the reservoir, meaning they will be filled with fluid and taken offline, and another 22 wells still have pending test results, a DOGGR spokesperson told NGI on Wednesday.
"All of those wells have undergone at least three tests -- initial temperature and noise logs required of all wells and a third or pressure test required of all wells prior to isolation," said spokesperson, adding that only one of the isolated wells had any additional testing, and that was a casing inspection log test, which it failed.
Seven of the isolated wells failed noise and temperature tests and another had anomalies in the first stage of testing. All of the rest passed the initial noise/temperature tests, the spokesperson said.
It was not immediately clear to DOGGR officials why SoCalGas has deferred doing the rest of the required tests on the group of isolated wells, but the state agency is focused on the viability of the wells, not gas supply issues, which are the responsibility of the California Public Utilities Commission (CPUC).
Nevertheless, SoCalGas within a year's time has to determine what it wants to do with the offline wells. "Some of them may be fine as they are for future use; others may require some remediation work, and still others may be permanently plugged and abandoned," said the spokesperson, adding that the state won't know how many wells fall into each category until the testing is conducted.
State protocol requires the wells temporarily put offline to be sealed at the bottom and filled with fluid above the seal, along with completing gas monitoring and a battery of tests every six months.
"If a well cannot successfully complete all necessary steps required in the safety review after one year of being removed from normal operations, the well shall be permanently taken out of service," the state guidelines say.
With 26 wells that have successfully completed all of the tests, 23 of which DOGGR has approved, SoCalGas is working to determine the number of completed wells that will be required to meet the CPUC's minimum withdrawal requirements for Aliso Canyon. When that point is reached, "the remaining wells will be temporarily plugged and taken out of service," the utility said in its latest report, referring to the isolated wells.
SoCalGas further reported that at some point DOGGR and the CPUC will begin their joint review and certification process, including conducting a public hearing, prior to Aliso Canyon being authorized to resume gas injections into the reservoir as outlined in a new state law (see Daily GPI,May 11).
Natural gas storage appeared on the national political and regulatory radar screen this year through the Obama administration's methane emission reduction initiatives (see Daily GPI,May 12) and the prolonged storage well leak at Aliso Canyon, which ended in mid-February (see Daily GPI,Feb. 18).
For Sempra Energy and SoCalGas, it has been an expensive wakeup call, according to the latest report from the utility, which estimated the cost it paid for thousands of nearby residents to be relocated during the four-month leak at approximately $500 million. The utility also provided more than 58,500 separate reimbursements to residents in 8,300 households that relocated temporarily.
An infrared methane detection system will be installed soon at Aliso Canyon, SoCalGas reported, but in the meantime, the utility has paid for the installation of 38,000 air filtration systems in 10,500 homes, 60 schools and 160 businesses in the upscale Porter Ranch community, which was developed within a mile of the base of the storage field over the past three decades and after the gas storage field opened in 1972.