The Energy Information Administration (EIA) is expected to release the revised estimates next month in what will be "a blow to the nation's oil future", writes Louis Sahagun, and also a disappointment for the state's economy. Sacramento was hoping that the new drilling would bring "2.8 million new jobs to California and boost tax revenue by $24.6 billion annually" according to a 2013 University of Southern California analysis [PDF].
The energy agency said the earlier estimate of recoverable oil, issued in 2011 by an independent firm under contract with the government, broadly assumed that deposits in the Monterey Shale formation were as easily recoverable as those found in shale formations elsewhere.
It isn't, thanks to California's geology - particularly its seismic activity.
Unlike heavily fracked shale deposits in North Dakota and Texas, which are relatively even and layered like a cake, Monterey Shale has been folded and shattered by seismic activity, with the oil found at deeper strata.
Sierra Club California, a strong opponent of fracking that has been advocating a moratorium included in Senate Bill 1132, greeted the news with caution. "The new estimates won't discourage the oil companies and oil industry service companies", states their press release.
Indeed, Tupper Hull, spokesman for the Western States Petroleum Association, stated, "We have a lot of confidence in the intelligence and skill of our engineers and geologists to find ways to adapt."
The move, however, is largely symbolic: There are no known oil leases in Santa Cruz County, nor has it been targeted by oil prospectors.
But other counties with proven oil reserves may follow. "Butte, Santa Barbara and San Benito counties are all considering fracking bans. Beverly Hills also recently passed a ban, becoming the first city to do so."