Higher-risk ‘Shallow Fracking’ More Common than Suspected: Study
Lessons for BC, Alberta in new Stanford report.
The study examined the frequency of so-called shallow fracking, described by the researchers as occurring less than a mile underground. Shallow fracking poses a greater risk to drinking water than fracking that occurs much deeper under the Earth’s surface.
Out of 44,000 wells fracked between 2010 and 2013 in the United States, researchers found that 6,900 (16 per cent) were fractured less than a mile from the surface and another 2,600 wells (six per cent) were fractured above 3,000 feet, or 900 metres.
“What surprised me is how often shallow fracturing occurs with large volumes of chemicals and water,” said lead researcher and environmental scientist Robert Jackson in an interview with The Tyee.
The majority of shallow fracking now takes place in Texas, California, Arkansas and Wyoming. Although the study largely excludes Canada, shallow fracking also takes place in Saskatchewan, Alberta, Quebec, Manitoba and British Columbia, and sometimes at depths less than 500 metres.
Due to poor data reporting by industry and its regulators, “the occurrence of shallow hydraulic fracturing across the U.S. is underestimated in our analysis,” added the study.
During shallow fractures, the industry injects fluids into vertical or horizontal wells to crack rock directly below or into groundwater. In many reported cases, the resulting fractures can travel up to 556 metres into other hydrocarbon zones, water formations or other energy well sites.
As a result, shallow fractures can connect to aquifers used for drinking water.
“Even fractures that do not extend all the way to an overlying aquifer can link formations by connecting them to natural faults, fissures or other pathways,” explained the study.
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