Production from the Marcellus gas shale generated international interest when methane accumulated in the surface housing of a water well pump and exploded.
Production from the Marcellus gas shale generated international interest when methane accumulated in the surface housing of a water well pump and exploded. The Pennsylvania Department of Environmental Protection (PA-DEP) immediately investigated and determined the cement had insufficiently isolated shallow methane-bearing sands (not the Marcellus gas shale) and methane from these sands was leaking into ground water. The media immediately seized upon the story and painted a picture of an industry unable to manage risk. The reputation of gas shale was further darkened by a Hollywood polemic called, Gasland, a documentary based loosely on facts. Later there were two highly publicized blowouts from Marcellus wells and some surface spills that added strength to those who argued against industry. The biggest public fear was the frack fluid could, somehow, flow uphill more than 2000 meters to contaminate groundwater. Of course, there are a number of physical laws such as the law of gravity and the law of buoyancy that prevent this from happening. Since the initial hype by the media, studies by both the US Environmental Protection Agency (EPA) and PA-DEP have shown beyond a shadow of a doubt that no frack fluids have contaminated groundwater in the vicinity of the methane leaking from casing. Microseismic surveys have since shown that fracture stimulations travel laterally as much 300 m but are generally restricted in vertical growth to 100 m. The focus of the fracking debate has since shifted to overlap with the climate debate. The debate was further sharpened by academic studies claiming such a high rate of methane leakage during completion that the effect on global warming would be substantial even though burning methane releases about half the CO2 relative to that released by coal on a BTU basis.