Thursday, May 03, 2012

Computer model disputes presumption that impermeable rock layers will keep fracking fluids away from water

Chemicals used in hydraulic fracturing of oil and gas wells could migrate toward drinking-water supplies more quickly than previously thought, according to a study funded by two upstate New York organizations opposed to drilling and fracking in the Marcellus Shale region. Using computer modeling, the study found that natural faults and fractures in the ground, exacerbated by fracking, could allow chemicals to reach the surface in a few years.

Scientists have presumed some layers of rock were impermeable and would keep fracking chemicals trapped almost far below the surface. This view has been a "cornerstone of the industry's argument that fracking poses minimal threats to the environment," reports Abraham Lustgarten of ProPublica. The study's lead author, Tom Myers, said that view was false. "The Marcellus Shale is being fracked into a very high permeability. Fluids could move from most any injection process," he said.

The study was published in the journal Ground Water. It did not use sampling or case histories to assess contamination risks. It relied on a computer model to determine how fluids would move through the rock over time. The models predict that fracking will "dramatically speed up the movement of chemicals injected into the ground." It showed that fluids traveled distances in 100 years that would naturally take thousands of years. (Read more)

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