The Christmas weekend brought mixed news for Southern California Gas Co.'s (SoCalGas) efforts to contain a two-month-old natural gas well leak at its Aliso Canyon underground storage field 40 miles northwest of downtown Los Angeles.
Lawsuits, investigations and ever-louder public rebukes were aimed at the Los Angeles-based Sempra Energy utility just before the holiday weekend (see Daily GPI, Dec. 23).
Last Sunday, SoCalGas officials said their first relief well had completed the first three of five phases, reaching a 3,800-foot depth, and was on target to follow the seven-inch diameter pipe in the leaking storage well to its depth of more than 8,500 feet. But the target date for completing the first of two relief wells is still months away, between late February and late March. Plugging and sealing the well will come after that.
A SoCalGas spokesperson reiterated that "one of the challenges in drilling the relief well is finding a seven-inch diameter pipe from about 1,500 feet away several thousand feet below ground, while avoiding nearby underground pipe in other wells at the [3,600-acre, 86 Bcf capacity] storage field." The utility's contract drilling crews employed magnetic ranging technology to target the relief well drilling effort.
SoCalGas marks its pinpointing of the leaky well pipe as a milestone because it will now allow continued target drilling to interconnect with the critical seven-inch diameter pipe at the base of the well.
"The next challenge [in phase four] will be to maintain drilling at the proper distance, orientation and angle to the leaking well to follow it down below 8,000 feet of measured depth," the spokesperson said. It involves drilling for depth while maintaining precise positioning horizontally.
Completing the fourth phase may take until the end of March, SoCalGas is estimating in a worst case scenario; best case, end of February.
The final phase starts after the target drilling intercepts the leaking well pipe with the infusion of heavy fluids and drilling mud into the bottom of the well to stop the flow of gas upward from its source in the overall reservoir. When the gas flow is stopped, the drilling contractors will then pump cement into the well to permanently seal the leak.
Work on a second relief well as a backup continues with grading of a second drilling pad set to be completed early next year and drilling to start by the end of January. That drilling operation, mirroring the work on the primary relief well, also will take three to four months, and the secondary well will operate entirely independent of the primary relief well, SoCalGas officials said.