GEOSPATIAL DATABASE OF VOLUNTARILY DISCLOSED HYDRAULIC FRACTURING OPERATIONS AND CHEMICALS IN CALIFORNIA, 2012

Currently, the California Division of Oil, Gas and Geothermal Resources is writing draft rules regulating hydraulic fracturing, a method of enhanced oil recovery that has been under scrutiny for the last several years mainly due to its risk of groundwater contamination. Public concern has prompted regulations that require producers to disclose online the ingredients they use in their hydraulic fracturing fluid. This method of disclosure has provided abundant information to the public but has so far lacked a unified, well-organized database for comprehensive analysis of these chemicals.

In order to better investigate the spatial distribution of chemicals used during hydraulic stimulation in California we compiled individual hydraulic fracturing fluid product component information disclosures from the online database FracFocus of all voluntary disclosures in the year 2012. Data was downloaded in PDF format, manually cleaned, then reformatted to create a searchable ArcGIS geospatial database. Searchable data includes: chemicals used, the maximum concentration of each chemical in the fracture fluid, date completed, operator name, total water volume, and true vertical depth.

Spatially plotted three-dimensional data shows most hydraulic fracturing in California occurs in conventional oil fields at moderate depths (average ~2,900 feet), and as shallow as 860 feet in the well-developed oil fields on the west side of the San Joaquin Valley, which are shallower than hydraulically stimulated wells in other states. In addition, we generated a list of the most-used chemicals in California during 2012. Preliminary results indicate that glutaraldehyde, a biocide which has received attention because of studies indicating possible public health risk, has generally been used by a single operator in deeply fractured wells (average ~8,000 feet).

We emphasize that our study is limited by an incomplete dataset due to the voluntary nature of disclosure in 2012. However, similar techniques should provide a much clearer view of fracking beginning with mandatory disclosures in 2014.