http://www.cnbc.com/id/101692873

It also means a reserve containing two-thirds of the shale oil crucial to America's vaunted shale energy boom is actually "stagnant," analyst John Staub, who led the agency's study, told the newspaper.

Experts said Monterey Shale still could become more productive as technologies and methods adapt to deal with the seismic problems in the area's rock formation.