Fracked Wells Can Pollute Groundwater, But Solution May Be Straightforward, Study Shows
One of the most alarming images from the fracking debate has been residents near gas wells igniting their tap water.
Until now, it’s been hard to say for sure how the gas got there. Methane can occur naturally in groundwater.
So a team led by OSU geochemist Tom Darrah developed a novel method for tracing the movement of the methane back to its source. They looked at 133 contaminated water wells in 20 locations in Texas and Pennsylvania.
"The bad news is that in a small subset of wells, there does appear to be evidence for man-made release of methane into shallow aquifers," Darrah said. "But the good news is that in cases where contamination existed, it appeared to be a problem with well integrity, as opposed to a problem with hydraulic fracturing."
That’s an important distinction. Critics have feared fracturing deep shale formations with high-pressure water and chemicals could free gas to flow upward outside wells, and into groundwater. If that were possible, it would be hard to prevent.
But Darrah's team found no evidence of that. Instead, he said, the problem is one common to traditional gas wells: leaky walls.
"So I think what that suggests is that with improvements in well integrity, we can probably eliminate most of the problems we’re seeing," Darrah said.
Fracking isn’t entirely off the hook yet. Darrah said since the process exposes wells to incredibly high pressure, it’s possible fracked wells might weaken faster than traditional ones. He said he’s looking into that.