SHAFTER, Calif. — A bustling city is sprouting on five acres here, carved out of a vast almond grove. Tanker trucks and heavy equipment come and go, a row of office trailers runs the length of the site and an imposing 150-foot drilling rig illuminated by football-field-like lights rises over the trees.
It’s all been hustled into service to solve a tantalizing riddle: how to tap into the largest oil shale reservoir in the United States.
Across the southern San Joaquin Valley, oil exploration sites have popped up in agricultural fields and on government land, driven by the hope that technological advances in oil extraction — primarily hydraulic fracturing and acidization — can help provide access to deep and lucrative oil reserves.
The race began after the federal Energy Information Administration estimated in 2011 that more than 15 billion barrels of recoverable oil is trapped in what’s known as the Monterey Shale formation, which covers 1,750 square miles, roughly from Bakersfield to Fresno.
But getting at that oil isn’t easy. The Monterey Shale is unlike other oil shale formations across the United States. In those booming oil fields, reserves are pooled in orderly strata of rock. Once the rock is cracked open by fracking or other means, operators can sink a single well with multiple horizontal shafts and pull in oil from a wide area.