Stanford scientist's investigations show that drinking water sources may be threatened by thousands of shallow oil and gas wells mined with the controversial process of hydraulic fracturing. A new study suggests safeguards.
The United States now produces about as much crude oil as Saudi Arabia does, and enough natural gas to export in large quantities. That's thanks to hydraulic fracturing, a mining practice that involves a rock-cracking pressurized mix of water, sand and chemicals.
Ongoing research by Stanford environmental scientist Rob Jackson attempts to minimize the risks of "fracking" to underground drinking water sources.
The most recent such study, published in Environmental Science & Technology, finds that at least 6,900 oil and gas wells in the U.S. were fracked less than a mile (5,280 feet) from the surface, and at least 2,600 wells were fracked at depths shallower than 3,000 feet, some as shallow as 100 feet. This occurs despite many reports that describe fracking as safe for drinking water only if it occurs at least thousands of feet to a mile underground, according to Jackson.
The authors also estimated water use for hydraulic fracturing in each state. The states with the highest average water use per well were Arkansas, Louisiana, West Virginia and Pennsylvania.
Perhaps most surprisingly, the researchers discovered that at least 2,350 wells less than one mile deep had been fracked using more than 1 million gallons of water each. Shallower high-volume hydraulic fracturing poses a greater potential threat to underground water sources because there is so little separation between the chemicals pumped underground and the drinking water above them.
"Shallow hydraulic fracturing is surprisingly common," said Jackson, the Michelle and Kevin Douglas Provostial Professor in the School of Earth, Energy & Environmental Sciences and a senior fellow at the Stanford Woods Institute for the Environment and the Precourt Institute for Energy. "The places where hydraulic fracturing is both shallow and water-intensive may need additional safeguards."
For example, Arkansas had more than 300 wells fracked shallower than 3,000 feet, using an average of 5 million gallons of water and chemicals. Other states that fracked wells shallower than 3,000 feet using more than a million gallons each included New Mexico (16), Texas (10), Pennsylvania (seven) and California (two).Read more by clicking here.
Connect with us on Facebook and Twitter!