The escape of tons of natural gas from storage under a Los Angeles
neighborhood is not likely to be fixed for at least another two months
because of the specific dynamics of the leak, according to officials.
The leak at Porter Ranch, already several months old, has forced the
relocation of several thousand residents who said the stench made them
sick.
The Los Angeles Times reported on Saturday
that the leak persists because workers were unable to plug it and
instead have the painstaking task of drilling two relief wells.
The natural repository is huge – nearly one cubic mile at a depth of a
mile and a half, according to the newspaper – and holds natural gas
brought from as far away as Canada. The gas company holds it
underground, then distributes it to nearly 22 million customers in the
region.
Southern California Gas tried to plug the damaged well after the leak
began in October, but both an ice blockage and upward pressure
averaging 2,700 pounds per square inch wouldn’t let the mixture of mud
and brine work.
Amid concerns that trying to force the mixture down might create a
larger leak, the company decided to drill two relief wells, said Jason
Marshall, chief deputy director of the California Department of
Conservation, which regulates natural gas wells.
If all goes to plan, those wells will intersect the damaged well
where it meets the capstone, about a mile down. Workers hope that will
let them plug the well below the damaged, leaky section. The cause and
exact location of the leak are unclear, though Marshall said engineers
speculate it is about 500ft underground.
Marshall suspects age is a factor - the well began operating in 1954, according to Conservation Department records.
Drilling on the first relief well began 4 December, but will take
weeks to complete. Drilling of the second well is expected by 20
January, Marshall said – it’s a backup, in case the first one misses the
existing 7-in pipe or is unable to deliver enough brine and mud to stop
the leak.
Trying to intercept at such a depth, Marshall told the newspaper, “is
a little like trying to hit a quarter-inch target from the distance of a
football field”.
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