The drive to replace coal-burning electricity with natural gas continues to run into environmental speed bumps.
Research scientists writing for Proceedings of the National Academy of Sciences of the United States of America (PNAS) report that while directional drilling and hydraulic-fracturing technologies are dramatically increasing natural-gas extraction, the aquifers overlying the Marcellus and Utica shale formations of northeastern Pennsylvania and upstate New York show systematic evidence of methane contamination of drinking water associated with shale-gas extraction.
The complete PNAS report directly cites hydraulic fracturing as a contributor: “the process of hydraulic fracturing generates new fractures or enlarges existing ones above the target shale formation, increasing the connectivity of the fracture system. The reduced pressure following the fracturing activities could release methane in solution, leading to methane exsolving rapidly from solution, allowing methane gas to potentially migrate upward through the fracture system.”
Active gas-extraction areas having one or more gas wells within a 1-kilometer average not only imperil drinking-water wells, they are also potential explosion hazards, the report states.
The report continues: “These δ13C-CH4 data, coupled with the ratios of methane-to-higher-chain hydrocarbons, and δ2H-CH4 values, are consistent with deeper thermogenic methane sources such as the Marcellus and Utica shales at the active sites and matched gas geochemistry from gas wells nearby. In contrast, lower-concentration samples from shallow groundwater at nonactive sites had isotopic signatures reflecting a more biogenic or mixed biogenic/thermogenic methane source.”
The researchers concluded “greater stewardship, data, and – possibly – regulation are needed to ensure the sustainable future of shale-gas extraction and to improve public confidence in its use.”
Beyond renewable energies, natural gas is one of the cleaner energy sources out there for those wishing to leave a green footprint. However, the techniques being used to obtain this gas are starting to make some worry.
As previously reported in CleanTechnica, during the last Congress, the House Committee on Energy and Commerce launched an investigation to examine the practice of hydraulic fracturing in the United States. The committee asked the 14 leading oil and gas service companies to disclose the types and volumes of the hydraulic fracturing products they used in their fluids between 2005 and 2009 and the chemical contents of those products.
For those interested in knowing more, visit FracFocus — a chemical disclosure registry operated by the Groundwater Protection Council and the Interstate Oil and Gas Compact Commission.
The details are here for all lookers wanting to search for information about the chemicals used in the hydraulic fracturing of oil and gas wells.
Photo: from the J Henry Fair exhibit at the 2011 Earth Day Fair in Grand Central. Location of site in Dimock, Pennsylvania.
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