The Environmental Protection Agency (EPA) defines fracking or hydraulic fracturing as a “well stimulation process used to maximize the extraction of underground resources; including oil, natural gas, geothermal energy, and even water.”
In a general sense, fracking requires injection of high-pressure fluid (generally water) mixed with chemicals to create cracks in the geologic layers deep below the surface. These cracks, or new channels, enable extraction of underground resources, which otherwise would stay there intact.
This approach is particularly important if resources are trapped in fine-grained rocks, such as shale. Resources trapped in shale formation are common around the world. According to a 2012 U.S Geological Survey (USGS) report, shale formations trap 10 percent of the world’s crude oil and 32 percent of the world’s natural gas resources. According to the same report, about 26 percent of U.S. crude oil and 27 percent of natural gas resources are trapped in shale formations.
The commercial use of hydraulic fracking in the United States started in 1949. In the past 65 years, fracking technology and drilling technology have advanced to such an extent to propel the United States to becoming an energy superpower.
Today, according to the U.S. Energy Information Administration (EIA), fracking is responsible for 3.5 million barrels per day of oil production, 45 percent of the U.S. total. It also produces 40 billion cubic feet per day of natural gas production, 60 percent of the U.S. total.
Hydraulic fracking increases stress or pressure on geologic formations to extract resources from fractured pathways. A similar process also occurs naturally, when fluid trapped in geologic formations comes out through naturally created fractures caused by periodic seismic events.
Hydraulic fracking techniques require extensive study, as geologic systems are different from one place to another. Generally, hydro-geological study of a site and design of a hydraulic fracking process itself require extensive data collection, which is generally not available to the general public or the scientific community at large. This is due to the competitive nature of oil and gas companies in their use of specific hydraulic fracking techniques.
Recently, the Groundwater Protection Council and Interstate Oil and Gas Compact Commission created FracFocus to share chemical data on hydraulic fracturing. However, not all companies participate in the chemical disclosure registry. And critics contend that the data presented there is insufficient and, at times, inaccurate.
Hydraulic fracking is regulated as a safe practice, but researchers and scientists across the globe argue that it is linked to surface and groundwater contamination; diminished streamflow; stream siltation; habitat loss and fragmentation; localized air, noise and light pollution; climate change and seismic hazards. Due to these concerns, hydraulic fracking is restricted or even banned at various places around the world, including Santa Cruz County, here in California.
To resolve these scientific concerns, observers urge oil and gas companies, government organizations, scientific communities and the general public to work together. The EPA proposed one such effort in 2011, to study the impact of hydraulic fracturing on drinking water resources.
USGS scientists have noted that at some locations, the seismicity coincides with the injection of wastewater in deep disposal wells. USGS is coordinating research with other government organizations and universities to better understand and manage risks associated with injection-induced earthquakes.
Hydraulic fracking is considered key to unlocking Southern California’s vast Monterey shale resources. Per a report published in 2011 by the EIA on U.S. shale gas and oil resources, the Monterey/Santos shale in Southern California is estimated to hold 15.4 billion barrels, or 64 percent of the U.S. total shale resources. California’s shale resource extractions have been compared to the gold rush era of the 1840s.
According to records of the California Department of Conservation, fracking has been reported in some wells near Orange County’s northern border. The Monterey Formation, which extends to north Orange County, is an exceedingly heterogeneous, biogenic-rich (siliceous, calcareous and carbonaceous) deposit, and only a minor fraction of its volume would be considered a true “shale.”
This implies that the methods that could be used for hydraulic fracking are going to be different for Monterey shale. Therefore, some would argue that the hydraulic fracking associated with California’s Monterey shale requires extensive risk assessment to ensure public health safety and prosperity of the region.
Phoolendra Mishra holds a Ph.D. in hydrology from the University of Arizona and is an assistant professor of environmental and civil engineering at Cal State Fullerton.