t may surprise some people to know that California is the fourth largest producer of crude oil in the United States and has a long history
of oil exploration. Since the 1860s, wells in Kern County and Southern California have been tapped for more than 500,000 barrels of oil each day. Now, the practice of going after the supply of oil that was previously unat- tainable is being scrutinized to make sure it does not contaminate precious underground water supplies.
The Monterey Shale formation. 4
The technique of hydraulic fractur- ing, or “fracking,” injects high pressure volumes of water, sand and chemicals into existing wells to unlock deposits of natural gas and oil. Fracking has drawn attention because of the fear by some that the unknown mixture of chemi- cals put into the ground could migrate to drinking water sources. Another concern is the possible link between fracking and seismic activity. “Of course, I am concerned with groundwater quality here in the L.A. Basin; there’s an awful lot of oil drill- ing going on here, and if fracking is a potential problem, I want to know more about it,” said Ted Johnson, chief hydrogeologist with the Water Replen- ishment District of Southern California (WRD), at a July 24 symposium on fracking in Long Beach sponsored by the Groundwater Resources Associa- tion of California (GRA). WRD’s service area includes 30 mapped oil fields and 9,700 oil and gas wells. Oil and groundwater have been pumped together for more than 100 years and even with the advent of fracking, the district is not aware of any problems with shallow groundwater contamination originating from deep in the oil reservoirs, Johnson said. “I certainly know there are a lot of cases of petroleum contamination of groundwater from surface sources – the