Using samples from 479 wells in 12 counties across the Barnett Shale, researchers concluded that high levels of methane found in groundwater sources were “probably from shallow natural gas deposits, not natural gas leaks caused by hydraulic fracturing operations in the underlying Barnett Shale.”

This finding builds on research released early last year, which found that methane in Parker County well water was “likely natural,” a conclusion that the Texas Railroad Commission (RRC) also reached during its 2014 investigation. As the latest study points out:

“In the following discussion, we show that the overall body of evidence that is, sampling results aided by earlier observations, strongly suggests a natural origin for the dissolved methane in the Parker-Hood cluster.”

To assess possible sources, researchers examined major ions and carbon isotopes present in the water, as well as well depth and the locations of each well.

The researchers concluded that there are plenty of natural explanations for the methane concentrations:

“Trying to prove a negative in the context of this study, that is, that no oil or gas well ever leaked natural gas is impossible; however, if a leak occurred, it was small enough not to noticeable alter the natural system. In other words, there is no need to invoke gas leakage to explain field observations. Structural and stratigraphic features explain the presence of thermogenic methane in shallow groundwater.”

The study also notes that there is “no correlation” between water wells with high levels of dissolved methane and their proximity to hydraulically fractured wells. From the UT news release:

“In addition to chemical evidence, the researchers found a strong correlation between water well proximity to the Strawn Group and high methane levels.There is no correlation between high-methane wells and the distance to the nearest hydraulically fractured wells.”

Of the possible sources, the researchers conclude that the methane is most likely from shallow zones such as the Strawn formation – which is not used for natural gas development – as opposed to the Barnett Shale. According to the study:

“In particular, the noble gas content shows a long geological interaction with the Strawn sediments. The dissolved gas does not originate directly from the Barnett Shale, but rather from the Strawn accumulations charged from the Barnett Shale.”

Researcher J.P. Nicot explains how contamination through such a pathway could take place, stating:

“Over geologic time, methane has accumulated into these shallower reservoirs…These fresh-water well are very close to these shallower reservoirs and may be the source of the methane."

Overall, the evidence from this latest study, as well as findings from previous reports and investigations, overwhelmingly supports the conclusion that methane found in Parker and Hood County water wells is naturally occurring.

Environmental activists have claimed dissolved methane in this region is “proof” of contamination from fracking. But scientific data show otherwise.