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Using Oilfield Chemical Analyses To Determine Salinity Gradients And The Depth To Underground Sources Of Drinking Water In Kern County's Oilfields.


The use of well stimulation techniques such as fracking and acidizing to recover remaining oil reserves as well as to unlock new sources of oil and gas from shales has increased in many areas of the country. While this has caused an increase in US oil production and a consequent independence from foreign sources of oil, it has also created great public concern about its potential to negatively impact groundwater supplies. As a result of these concerns, the California legislature passed SB 4 (the so-called ‘fracking bill’) in September 2013. The bill requires the state to identify potable groundwater resources which require protection and develop a monitoring program to protect these resources in areas where fracking occurs. In the past, oil producers set surface casing to protect the base of fresh water (BFW) which is defined as waters containing less than 3000 ppm total dissolved solids (TDS). However, the US Environmental Protection Agency (EPA) requires state agencies to protect Underground Sources of Drinking Water (USDW). Waters classified as USDW's have less than 10,000 ppm TDS and are considered to have potential for remediation for agriculture, landscaping and industrial uses. In this study we examine data from geochemical analyses in oil and water wells in order to determine the depth to USDW's in various oilfields throughout Kern County, California. The depth to the base of the USDW's is controlled by a number of factors including location, depth and stratigraphy.