A state scientific review of what’s known about fracking in California finds the controversial oil and gas production technique is used in nearly half of all new wells, particularly in four Kern county oil fields in the southern part of the San Joaquin Valley.

An independent scientific team is reviewing research about fracking before new regulations monitoring and limiting the practice take effect this summer. Both actions are the result of SB4, a state law sponsored by Agoura Hills State Senator Fran Pavley.

Hydraulic fracturing involves shooting water, chemicals and sand into wells to free oil trapped between rock layers. Over the last decade, between 125 and 175 wells a month were subject to fracking; most of those were in Kern County.

The team found the type of fracking done in California uses less water but more concentrated chemicals than the fracking done in other states. They also found that other extraction techniques --and not fracking -- are likely better adapted to reaching the state's remaining oil reserves.

Still, the team found a fifth of the state’s oil comes from fracking.



“The reason only 20 percent of the oil is produced this way is because the wells that are being hydraulically fractured are not as efficient as other forms of production,” said Dr. Jane Long, the scientific team’s co-leader. “We fracture a lot more wells and get less than a proportionate amount of oil from those wells.”



Environmental groups are criticizing the scientific survey as flawed and incomplete. They say its focus on just the extent of fracking in the state is too limited, and they’ve expressed frustration that the report is coming out after language for fracking regulations has been finalized.

The release of just the first volume of science “shows the urgent need for Gov. Brown to institute an immediate moratorium on fracking and other dangerous oil and gas development," said the Center for Biological Diversity’s Kassie Siegel. In a written statement, Siegel said that California should “follow the lead of New York,” where last month Governor Andrew Cuomo banned hydraulic fracturing.

But several members of the independent scientific team pointed out that the high-volume, horizontal wells are nowhere to be found in California, where vertical, shallow wells are more prevalent. “If California decided to ban what New York banned, it would make practically no difference in California,” Long said.

The state plans to release more analysis about the risks of fracking on air quality, water quality and induced earthquakes in July, as well as a volume of case studies of the practice. New regulations created under SB4, published earlier this year, will take effect July 1.