Prior posts have noted studies showing that adverse impacts arising from fracking operations often result from defective wells and waste ponds. A new study supports prior research with its finding that contamination of drinking water supplies arise from faulty wells.
The researchers used noble gases to trace the path of methane since these inert chemicals are not affected by microbial activity or oxidation. By measuring the ratios of the noble materials to the methane they were able to accurately determine the distance to the likely source. The scientists analysed results at 113 wells in the Marcellus shale in Pennsylvania and 20 in the Barnett shale in Texas. They found eight clusters of wells with problems.
The study found that "Gas geochemistry data implicate leaks through annulus cement (four cases), production casings (three cases), and underground well failure (one case) rather than gas migration induced by hydraulic [activities] deep underground."
The report can be found at: http://www.pnas.org/content/early/2014/09/12/1322107111.
The study supports the implementation of standards and requirements directed and related to well integrity.