A report recently released by the United States Geological Survey (“USGS”) found that water wells in the Fayetteville Shale of north-central Arkansas are, thus far, not contaminated by the area’s hydraulic fracturing activities.
The Fayetteville Shale is a relatively small shale play, with 4,000 wells drilled as of April, 2012. The concern of area residents that their water wells were contaminated by shale activity prompted the USGS’ involvement and subsequent testing.
The USGS sampled 127 domestic water wells in the Fayetteville Shale area for major ions and trace metals, with some samples tested for methane and carbon isotopes.
The USGS also looked for elevated salt levels, as well as methane in the groundwater supply. All levels were found to be consistent with or in lower concentrations than historical records for samples collected between 1951 and 1983.
The most frequently analyzed constituent was chloride, a large component of the produced water accumulated during the hydraulic fracturing process and a significant indicator of whether produced waters had entered shallow groundwater. Interestingly, the historical data revealed statistically larger chloride concentrations than in the samples collected for this study.
The report concludes that while the test results do not indicate an improvement in overall water quality, there is no evidence of groundwater contamination by fracturing fluids or methane in the study area.