Workers started using a device to contain an oily mist that has been surfacing from a massive methane leak at a well site in Southern California Gas Co.’s storage facility above Porter Ranch.
The seepage is the result of changing dynamics deep underground where the natural gas stores under pressure in the pores of sandstone rock in the company’s Aliso Canyon Storage Facility in the Santa Susana Mountains.
The leak, discovered Oct. 23, is causing a drop in pressure in the storage field and SoCalGas is accelerating that process by putting more gas into its distribution system.
Called “demister pads,” the devices contain a mesh screen and workers place them where seepage is occurring.
“They trap droplets that mix with the gas as it comes up,” SoCalGas spokeswoman Kristine Lloyd said of the system. “They are laid over where the gas is coming up, and as the gas flows through, it traps the oil and water.”
The pads end up encased in a 60-foot-long, 8-foot-wide steel frame about a foot tall. It holds 40 pads, officials said.
Three other frames are under construction, including one that is 100 feet long, and workers will install them when the weather permits.
“They (the demister pads) are necessary because as the reservoir pressure declines, fluids (oil and water) encroach into the reservoir and are then carried to surface with the gas. The amount of misting is partially dependent on wind conditions,” said Don Drysdale, spokesman for the state’s Department of Oil, Gas and Geothermal Resources.
SoCalGas acknowledged late last month that some oily residue droplets have been encroaching on the neighborhood adjacent to the storage facility in Porter Ranch.
“The dark brown residue may be related to non-toxic brine solution released as part of the SoCalGas’ leak control process. The brine solution may have contained trace amounts of oil naturally occurring within the leaking well’s reservoir, and may have been carried by the wind to properties immediately adjacent to the facility, particularly when very strong winds blow in that direction,” Lloyd said.