A top official in California's Department of Conservation (DOC) earlier this week told local news media that an injection practice used by Southern California Gas Co. (SoCalGas) at the time it discovered a natural gas storage well leak last October needs further review by state regulators. It is part of the state's investigation of the prolonged leak, which has displaced thousands of local residents.
The practice, which Jason Marshall, chief deputy director at DOC, called common, involves using both the 2-7/8-inch well pipe and its 7-inch diameter casing to inject gas supplies into the 8,500-foot deep storage well. Petroleum engineering professionals said the safer way to inject gas is through only the pipe, leaving the casing clear.
Nearly three months later, the well (SS-25) at SoCalGas' Aliso Canyon underground storage field in the far northern end of the Los Angeles San Fernando Valley is still spewing methane into the atmosphere, although at slower rates than earlier (see Daily GPI, Jan. 14).
Marshall told local news media that the practice of using both the pipe and casing for injection is something that DOC's Division of Oil, Gas and Geothermal Resources (DOGGR) needs "to look at seriously."
A DOGGR spokesperson told NGI on Wednesday that Marshall was not saying that the practice over-pressurized the well. "Sliding sleeves in wells are designed to allow injection or [withdrawal] of gas through the well's narrower, internal production tubing and through the well casing that surrounds the tubing," the spokesperson said.
He confirmed that SoCalGas uses this practice at Aliso Canyon, moving gas through both the casing and tubing. "We don't yet know whether that practice is a factor in the leak," the DOGGR spokesperson said. "That will be looked at in our investigation."
NGI last Tuesday asked SoCalGas officials to clarify the use of the practice, but as of Thursday no one from the Sempra Energy gas-only utility had responded.
Separately, on Wednesday the South Coast Air Quality Management District (SCAQMD) postponed a decision by its hearing board on a proposed abatement plan for the leak. In response to concerns of the local Porter Ranch residents, the SCAQMD will meet in the residential community when it takes up the issue.
Residents who are part of the Save Porter Ranch group are urging the air pollution regulators to amend their proposed abatement order to call for the closure of the overall Aliso Canyon facility, which serves the 21 million population Southern California region.
On Thursday, attorneys for Porter Ranch residents sent a four-page letter to the SCAQMD alleging that a stipulated order the air quality regulators reached with the gas utility is "deceptive" and eventually will "immunize SoCalGas from liability for its massive negligence at Aliso Canyon."
Among the residents' allegations are that SCAQMD staff found 15 different wells at Aliso Canyon now with "minor leaks," state regulators are relying on a SoCalGas-paid consultant for the root cause analysis of the SS-25 well leak, and language in the order opens the possibility of the utility resuming gas injections at the storage facility.
"It appears that SoCalGas has lost control of the entire oilfield, a possibility that must be fully disclosed to the public through evidence," the residents' attorneys said in the SCAQMD letter.