Researchers quick to point out “no correlation” between methane concentrations in water wells and closeness to fracked wells
By Matt Mandel, EnergyInDepth
Methane found in North Texas water wells is from natural sources and not from hydraulic fracturing, according to a recent peer reviewed study from researchers at the University of Texas at Austin.
The study contradicts an infamous scene in Gasland Part II, when a local landowner presented a “flaming hose,” which the audience was led to believe was a result of fracking.
Researchers analyzed water well samples in 12 counties across Texas’ Barnett Shale, but notably focused on Parker County and Hood County, an area that has been at the center of controversy regarding fracking for several years.
Environmental activists have linked water quality problems to fracking, despite a number of studies and analyses finding a natural explanation.
The UT team examined over 500 well water samples from nearly 480 different wells across the Barnett Shale, analyzing methane concentrations, major ions and carbon isotopes in the water.
They also examined water well depths and distances to gas wells, all to help determine the source of the methane. The authors also relied on previous research in the region to inform their findings.
Ultimately, the study concludes that methane in the Parker-Hood cluster wells was from shallow reservoirs, and not the Barnett. According to the study:
“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.”
Controversy surrounding well water methane concentrations in Parker County began over six years ago, when a video of a landowner igniting water from a garden hose spurred then U.S. EPA Region 6 Administrator Al Armendariz to issue an “endangerment order” against a local gas driller.
The video was later found to be a ploy to get the EPA involved, as the landowner had hooked the hose up to a gas vent.
However, activists continued to argue that the methane was linked to fracking, even after a 2014 investigation by Texas Railroad Commission (RRC) found that the methane was naturally occurring from the Strawn formation.
In fact, the UT researchers conclude there are multiple natural explanations for such contamination:
“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 most likely cause of methane concentrations in the Parker-Hood cluster wells is from shallow natural gas reservoirs from the Strawn formation – directly supporting the RRC’s 2014 findings. As the researchers note:
“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.”
In the press release, one of the researchers, J.P. Nicot, explains how methane from the Strawn could contaminate the Parker-Hood cluster wells:
“Over geologic time, methane has accumulated into these shallower reservoirs…These fresh-water wells are very close to these shallower reservoirs and may be the source of the methane.”
But while the wells’ close proximity to shallow pockets of natural gas could describe a potential pathway, the researchers are quick to point out that there is “no correlation” between methane concentrations in water wells and their closeness with fracked wells. As the study notes:
“There is no strong correlation between dissolved methane concentrations and distance to the nearest gas well (Figure 5). The correlation is even weaker when considering well density and lateral length density vs. distance to the nearest gas well. This is certainly true at the level of the entire Barnett Shale play but also in the Parker-Hood cluster area.”
Faced with all evidence for a natural source of methane in the Parker-Hood cluster water wells, the authors flatly conclude that fracking is not to blame:
“Companion analyses (Wen et al. 2016) strongly point to Strawn shallow gas accumulations as the source of the dissolved gas that is supported by the circumstantial evidence presented in the paper: collocated high dissolved methane and shallow gas accumulations, numerous historical observations of dissolved methane at the western edge of the Trinity Group outcrops, weak to no correlation between dissolved methane and distance to gas wells, and possibly well-established methane biodegradation. It follows that the presence of high dissolved methane is almost certainly natural.” [emphasis added]
With so much proving that the methane found in Parker County and Hood County water wells is naturally sourced, not from hydraulic fracturing, this study is yet another nail in the coffin of activists’ claims about water quality issues in North Texas.