Natural gas contamination of groundwater often attracts media attention, drawn by the startling spectacle of flammable tap water. A study published in September by a team of researchers from Ohio State, Stanford, Duke, Dartmouth, and the University of Rochester attempted to identify how gas infiltrates aquifers, focusing on the Marcellus and Barnett Shale regions. The researchers found that drilling activity was the cause of the contamination, but contrary to a common concern, fracking did not open up underground seams for natural gas to seep into groundwater aquifers.
The researchers hypothesized a number of potential ways for gas to reach groundwater aquifers, including microbial activity, naturally-driven gas migration along existing fissures, leaking from poorly cemented wells, leaks from abandoned wells, and gas migrating through fissures created by fracking. Each process would result in variations of the chemical makeup of the gases in the water. By measuring the composition, the researchers were able to identify the likely source of the pollution. Based on their findings, they concluded the most likely source of migrating gas is “well integrity problems.”
In an Ohio State University press release, lead author Thomas Darrah said the results were a cause for some optimism, because while they showed that human activity is causing contamination, building better wells is a relatively straightforward way to minimize contamination in the future.
Read the full study here.
Written by Stratecon Staff