“Simply put, [the rock layers] are not impermeable,” said the study’s author, Tom Myers, an independent hydrogeologist whose clients include the federal government and environmental groups.
“The Marcellus shale is being fracked into a very high permeability,” he said. “Fluids could move from most any injection process.”
…Where man-made fractures intersect with natural faults, or break out of the Marcellus layer into the stone layer above it, the study found, “contaminants could reach the surface areas in tens of years, or less.”
The study also concluded that the force that fracking exerts does not immediately let up when the process ends. It can take nearly a year to ease.
As a result, chemicals left underground are still being pushed away from the drill site long after drilling is finished. It can take five or six years before the natural balance of pressure in the underground system is fully restored, the study found.
Myers’ research focused exclusively on the Marcellus, but he said his findings may have broader relevance. Many regions where oil and gas is being drilled have more permeable underground environments than the one he analyzed, he said.
“One would have to say that the possible travel times for a similar thing in Arkansas or Northeast Texas is probably faster than what I’ve come up with,” Myers said.
New Study Predicts Frack Fluids Can Migrate to Aquifers Within Years – ProPublica