Environmentalists and shale gas drillers may both disagree about the level of uncertainty, but the sudden boom in shale gas drilling has raised a lot of questions about whether the horizontal hydraulic fracturing techniques used have any serious environmental consequences — questions which regulators are looking into.
One gas company, Cabot, was this month banned from drilling in Pennsylvania while it plugged three wells believed to have contaminated drinking water of 14 homes.
A Cabot spokesman said:
“It just isn’t scientifically fair to say in any short period of time that Cabot’s activities did or did not cause the methane in the groundwater,” he said.
A pioneering expert on Marcellus shale says that statement doesn’t reflect well on Cabot. But he argues the ill effects of shale gas drilling are also overstated by some.
Terry Engelder, a professor of geoscience at Penn State University and an authority on the Marcellus shale play, wrote in The Philadelphia Inquirer that while Cabot is correct to say that methane can naturally seep into water around the state, drilling is also known to accelerate the process.
Many private wells in the state have dissolved methane in their water, and people drink this water all the time with no ill effects. But if the volume of methane in the water is near saturation, it can collect in pockets of gas when underground pressure is released by water pumps that aren’t properly vented.
In the course of our research, my colleagues and students at Penn State have drilled into pockets of methane gas at depths of 500 to 2,000 feet. When such a pocket is penetrated, gas rushes up to the surface, blowing foaming, white water out of the well – much as carbon dioxide drives soda out of a shaken bottle. Fourteen families in the Dimock area have described milky-looking water in their wells.
Engelder says nearly a dozen shale gas companies are supporting the university’s research, and “more than one” has engaged it to help avoid these sorts of gas pocket problems. In other words, the potential problem is already acknowledged by the industry.
But, he adds, some shale gas critics make equally unfounded statements, including the preliminary paper by Cornell University biologist, Robert Howard, suggesting that shale gas could be more intensive than coal, when lifecycle emissions are considered, which we wrote about.
Natural resources, Engelder says, tend to bring out the worst arguments from both industrialists and environmentalists.
How good is natural gas, when lifecycle emissions are considered? FT Energy Source
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