A group of Duke University researchers have found a connection between natural gas drilling and higher levels of methane in drinking water in some parts of Pennsylvania and New York, according to a study released on Monday.
The study published in Proceedings of the National Academy of Sciences (see below) sampled water from 68 wells in areas where natural gas drilling has occurred. While most of the wells had some methane in them, water samples taken from wells within one kilometer of an active natural gas well had on average 17 times the levels detected in wells farther from active drilling.
These levels are considered dangerous in that they can allow explosive levels of the gas to build up in enclosed spaces.
The researchers “finger-printed” the gas found in the wells and concluded it came from the deeper shale formations that were being drilled at the time. This finding seemed aimed at addressing an issue that has come up in a dispute in North Texas in which Range Resources is accused of contaminating drinking water. An industry group has argued it’s gas from shallower formations that contaminated the wells in Parker County, Texas, and that excessive ground-water pumping was the likely culprit.
But back to the Duke study:
“Our results show evidence for methane contamination of shallow drinking water systems in at least three areas of the region and suggest important environmental risks accompanying shale gas exploration worldwide,” the Duke study said.
What the researchers didn’t find in their well samples were signs of the chemicals used in hydraulic fracturing.
According to Science, the researchers were surprised at how little peer-reviewed research there was on well-water contamination near well sites. That same lack of information is the reason researchers at the University of Texas told us last week they are conducting studies of the broad range of complaints that have been brought against shale drilling operations.
Rob Jackson, one of the Duke researchers, told us in an e-mail exchange that the only homes with previous complaints of gas in the drinking water were those in Dimock, Pa., where Houston-based Cabot Oil & Gas has been involved in one of the better-known disputes over gas drilling.
In Dimock the research didn’t always corroborate the homeowners’ claims, Jackson said, but some of the highest concentrations of methane in the water were in places where no known problems had been reported previously.
Oddly, a version of the Associated Press’ story on the study said the lack of frac fluids in the drinking water was “an unexpected finding.” Since most shale gas formations are many thousands of feet below aquifers where wells draw their water, many in the industry think it’s highly unlikely the chemicals from frac jobs can reach them.
The notion of natural gas getting into the drinking water because of poor well casing and cementing — a problem than can occur in any kind of well no matter where it is — isn’t that far fetched, however.
And as the researchers point out, it’s also possible that older, abandoned wells in the area that were not sealed off properly could also be conduits for natural gas to reach the drinking water.
Natural gas in one’s well water is bad news, no doubt about it. But knowing the real cause of the problem — i.e. bad well casing/cementing vs. fracking — makes a big difference in how you go about preventing the problem.
OK, if its poor casing jobs, then why are all the water aquifers in Texas and Oklahoma not filled with nat gas ?
The geology should not matter, because the breach occurs at shallow depths where the aquifers are located.
And why do the casing jobs in Pa suck so badly compared to the ones in Texas/Oklahoma/Louisiana/California et al ?
I can not take give these people an iota of credibility , as much as I try. I do not know geology and especially the geology of Pennsylania, so I think maybe its just strange up there compared to here.
But we have great experience with surface casing.
How can this be ?
Howdy Neighbor:
“But knowing the real cause of the problem — i.e. bad well casing/cementing vs. fracking — makes a big difference in how you go about preventing the problem.”
1) Deep gas generally means shallow gas as shale gas is the source rock for other accumulations. So it is not surprising that there is more shallow gas where shale source rock exists (this is like a “doy” in the industry… just like oil seeps in the GOM are an indicator that one might find something).
2) PA law still does not protect surface water like Texas law.
“And as the researchers point out, it’s also possible that older, abandoned wells in the area that were not sealed off properly could also be conduits for natural gas to reach the drinking water.”
3) Yup… especially when some were abandoned by pile driving a telephone pole into them.
Howdy Neighbor….
Uh, do these guys even look at previous research, like 1998 type of stuff?
http://geoweb1.tamu.edu/faculty/grossman/Zhang98GroundWater.pdf
Not Invented Here perhaps?
The methane concentrations reported in the study you posted are less than values that are naturally occuring in Texas groundwater.
There are no frac fluids and the concentrations are within normal values.
This does NOT mean there are not legitimate issues with waste water disposal and surface casing under PA law but…
this is silly.
When do dissolved methane thermogenic isotopic data automatically indicate leakage from production casings and not a natural occurrence from whithin thousands of vertical feet of formation? When does a n=68 data set offer a statistically valid relationship of methane in shallow groundwater wells to proximity to natural gas production? Where is the data on groundwater velocity and transport direction in relation to grioundwater methane detection and well proximity? Where are the statistics and maps of leaking underground storage tank sites, petroleum spills, pipelines, all active and abandoned oil & gas production well penetrations, and maps of coal and carbonaceous shale units for the same study area? Since when are biologists, ecologists, and their drone grad students qualified to do groundwater quality studies which completey oversimplify a complex system? Where the h–l is the USGS?
Just another case of joke 2nd rate academics making the science fit their environmental agenda in order to get some media face time and drum up some new funding options.
Very interesting. The rapid falloff of concentration vs. distance, especially from active sites, is hard to ignore. And the lengths they’ve gone to establish that it’s thermogenic gas vs. simple decomp are also convincing. But what’s lacking is evidence of the transport mechanism. Is it due to the frac’ing, at all? Or just up the wellbore, outside the casing?
There are some technical details in the paper that are widely overlooked. Just to take one for instance, it’s been reported that they did not detect frac fluids, others report they did not detect chemicals used in frac jobs. The fact is, they did not test for anything but the signal of saline frac fluids. They did not test for biocides, thinners, surfactants, slickeners, gelling agents, etc., etc., that might be used in a frac job. They simply did not test for those at all. ONLY saline frac fluids. You can see Dr. Jackson discuss this here:
http://www.wnyc.org/articles/wnyc-news/2011/may/09/study-links-gas-drilling-methane-contamination-drinking-water/
“There are many things in the fracking fluids that we couldn’t look for,” Jackson said. “We don’t know what they are. We don’t have the analytical capabilities in our labs here at Duke to analyze everything.”
Which kind of brings up the question, what the heck kind of lab is that, and why didn’t they ask companies or PA DEP for lists of frac chemicals they should test for? But regardless, this is one among several points that seems to be getting lost in translation somehow.
The original paper is here, it should be read carefully: http://www.nicholas.duke.edu/cgc/pnas2011.pdf