Southern California Gas Co. (SoCalGas) announced that its relief well project to stop the Aliso Canyon natural gas leak is proceeding ahead of schedule and the company expects to stop the leak by late February, if not sooner.
The relief well drilling began Dec. 4, 2015, and is expected to reach the bottom of the well at a depth of about 8,500 feet below the surface next month. Once the well is sealed, it will be taken out of service permanently.
"Our team of experts has been working around the clock since we started relief well operations in early December and we're pleased with the progress we've made thus far," said Jimmie Cho, senior vice president of gas operations and system integrity for SoCalGas. "Our top priority remains the safety of those working on the site and of the nearby community. We are focused on stopping the leak as quickly and safely as possible, mitigating the environmental impact, and supporting the community. Our schedule to control and stop the leak in February is consistent with the plan we have submitted to state regulators."
The most recent Aliso Canyon preliminary emissions estimates by the California Air Resources Board (CARB) were posted Jan. 12, showing estimated emissions have decreased more than 60 percent since CARB's peak estimates on Nov. 28, according to the latest CARB monitoring data. The estimated cumulative emissions released as a result of the leak are less than 1 percent of the state's annual total.
CARB releases rough estimates of the volume of gas leaking from the well based on data collected during periodic flights using monitors to measure methane. The flyover data provide an estimated emission rate at the time the flights are conducted, and are used to develop a rough estimate of the total methane leaked to date. As CARB also acknowledges, a more refined estimate of the actual emissions will be conducted once the leak is stopped and additional data is collected and reviewed.
SoCalGas has said it intends to mitigate the environmental impact of the actual amount of natural gas released from the leak.
In other developments:
- The South Coast Air Quality Management District (AQMD) released a preliminary assessment Friday that the level of benzene risk levels in the Porter Ranch community, based on 24-hour samples, approximated levels consistent with other parts of the Los Angeles basin.
- SoCalGas said today that after extensive design and study, and in consultation with the AQMD and other state agencies, it has decided not to install a gas capture system at the leaking well because of safety concerns expressed by its engineers. Design of a gas capture system began in November 2015, with the company's engineers and consultants studying various ways to build and install a gas capture system. However, a design was not identified that would attain the safety level that SoCalGas believes is required.