Remembering the Methane Express
111 Days at Aliso Canyon
This spring saw the completion of a 258-page third party analysis by Blade Energy Partners of well SS-25 at Aliso Canyon, CA, just north of Los Angeles. The analysis covered the direct causes and the root causes of this uncontrolled leak of 6.6 billion cubic feet of methane (otherwise referred to as natural gas) from this deep storage facility, 8,000 feet underground.
This event began on October 23, 2015 and vented gas from well SS-25 that was part of a storage field composed of 125 wells into permeable strata and maintained at a pressure of approximately 2,800 pounds per square inch. SS-25 was drilled to 8,500 feet as an oil well in 1954 and converted to gas storage after the oil had played out.
Thousands of people were driven from their homes by fumes. Schools and businesses were closed, and expensive home decontamination took months. Permanent health effects to residents during the active event or from building contamination are unknown.
Six attempts to kill the well by conventional means failed. Only when a relief well was drilled to intercept SS-25 below the leak at 900 feet, was control achieved. Sempra Energy’s subsidiary, Southern California Gas Company, was responsible for the Aliso Canyon facility.
(From the Blade Report’s Executive Summary, 5-16-19)