Another piece of scientific evidence has been published that suggests that the negative press over hydraulic fracturing may be unwarranted. As most of you are aware, there have been many accusations reported in the media that fracing allowed methane to enter and contaminate water wells. While methane is not particularly toxic, it is smelly, explosive and thus potentially dangerous. A new study that you can read here was published last fall in the Proceedings of the National Academy of Sciences. That study concluded that contaminated groundwater in Texas and Pennsylvania is not due to fracing but is primarily the result of problems with pipes and seals at natural gas wells, and particularly with annulus cement, production casing, and failure of the water wells themselves.
The study authors chose research areas in the Marcellus Shale and the Barnett Shale where the most complaints of water contamination were reported. The study addressed two questions: (i) are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic (i.e., resulting from the influence of human beings); and (ii) if fugitive gas contamination exists, what mechanisms cause it? The study was conducted by analyzing chemicals, like methane, in groundwater using noble gas and hydrocarbon tracers. This process allowed the researchers to determine if gas wells were contaminating the water, if so, which wells and also to determine which part of the drilling process or equipment was to blame. The proportions of elements such as methane, helium, neon, and argon in the groundwater demonstrated that these elements originated from leaky pipes and bad seals. If the contamination had come from fracing, the water would have exhibited different proportions of these elements.
The study identified eight discrete clusters of fugitive gas contamination overall, with seven in Pennsylvania and one in Texas and these results demonstrated contamination that had occurred over time. There were two cases during the study in which the water supplies experienced ten-fold jumps in methane level. A co-author of the study, Rob Jackson, an environmental science professor at Stanford University, said “I don’t think homeowners care what step in the process the water contamination comes from. They just care that their lives have changed because drilling has moved next door.” The lead author of the study, Thomas Darrah, a geochemist from Ohio State University, said this is good news because contamination from these sources is much easier to fix and is also more readily preventable.
The study also demonstrated that the scope of the contamination is fairly modest (although that is no comfort if it's your water supply that is contaminated). Out of 20,000 wells in drilled in Pennsylvania since 2008, the state has identified 243 cases of private water contamination that had been “impacted by oil and gas activities”. In the geographic areas in the study with the most complaints, only a minority of wells showed contamination with any relationship to natural gas drilling or production. The contamination in these cases was the result of naturally occurring methane in the water wells.
Obviously, the oil and gas industry must insure that none of their activities have any impact on potable water wells. However, if fracing is not the problem, we must stop the politically charged and emotional discussions about fracing that have no basis in fact and concentrate on fixing what needs fixing.
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