The Geological Society of America’s annual meeting was in full swing over the weekend with some 1,600 geologists meeting in downtown Pittsburgh. Prominent on the agenda is drilling in the Marcellus Shale.
A Penn State University researcher found that Marcellus shale gas drilling companies reused at least two-thirds of the water returned to the surface during 30 days of drilling.
"The industry is striving to reuse as much flowback as possible," said David Yoxtheimer, a hydrogeologist with Penn State’s Marcellus Center for Outreach and Research.
That’s largely due to the millions of gallons of water needed to drill the horizontal wells about a mile below the surface that are necessary to fracture the shale and allow the natural gas to flow to the surface, he said. Reusing the water reduces reliance on groundwater or municipal sources of water, reducing the environmental impact, said Yoxtheimer.
Daniel Soeder, a geologist with the U.S. Department of Energy’s National Energy Technology Laboratory in Morgantown, studied samples of drill cuttings, or bits of rock left over after drilling, as well as samples from well cores and Marcellus shale formations at the surface.
All three contain different levels of metals, chemicals and minerals found in flowback. Soeder’s research is preliminary, and he plans to conduct research on what causes the increased levels.
"What we really want to do is have some data to back this up so when regulations are put in place, there is data showing it really is needed," Soeder said. "One of the biggest issues about Marcellus is there’s just not a lot of data, so regulations are getting made and people are getting wound up, and there’s just nothing to back it up. So we’re trying to fill some of the blanks."
*Pittsburgh Tribune-Review (Mar 21, 2011) – Gas drillers reuse two-thirds of water, expert finds