Appalachian Basin

Cabot Says Duke’s Methane Conclusions Are The Only Hot Air Around

This is a cross-post of a recent piece on the Well Said Cabot blog that takes a closer look at assertions by researchers at Duke University.  Cabot posted the below to lay out the facts and encourage a conversation based on science.

Bloomberg published this piece, Cabot’s Methodology Links Tainted Water Wells to Gas Fracking, drawing upon conclusions from professors at Duke University and asserted that natural gas from Marcellus shale is leaking into domestic water wells in Dimock. Bloomberg even goes as far as to say:

Methane in two Pennsylvania water wells has a chemical fingerprint that links it to natural gas produced by hydraulic fracturing.

After a careful review by independent geologists, it is clear Duke’s findings are NOT based on any new research or any comprehensive investigation. Instead, the professors plotted the isotopic signature of methane from data released six months ago by the Environmental Protection Agency (EPA) – the same data the EPA used to determine that water in Dimock meets Safe Water Drinking standards – onto a graph then drew conclusions from it without properly considering the science required to identify the origin of natural gas.

Here is an overview of why Duke’s methodology and Bloomberg’s subsequent piece are wrong.

Duke’s conclusion relies on only identifying the isotopic signatures of methane and plotting them against other known signatures. Here is an explanation of how this technique works from Pittsburgh Geological Society:

Gases created by different processes have different chemical or molecular compositions and stable isotope signatures….Studies of carbon and hydrogen isotopes examine the differences between the isotope values of the sample being analyzed and those of an established standard.  These ratios are then plotted on graphs, to show that different kinds of natural gases segregate into different areas.

The independent geologists who disagree with Duke’s findings do not deny this technique can identify methane sources. Instead, they contend Duke’s decision not to use more sophisticated techniques for identification – which focus on unique characteristics – fails to definitely support the study’s conclusion. Thus, Bloomberg’s reliance on non-definitive conclusions undermine the credibility of the piece.

Here’s some information that was left out of the Bloomberg article:

  • Hundreds of hydrocarbon gas samples from Susquehanna County have been evaluated by experts using more sophisticated techniques to differentiate between the Marcellus and overlying deposits.
  • The Duke Professors never claimed that hydraulic fracturing was the reason that methane was introduced into the aquifers.

Here is what Bloomberg reported:  “the composition of the gas –its isotopic signature — falls into a range [Cabot] had identified as that of the Marcellus Shale, which it tapped through hydraulic fracturing, or fracking.”

  • Hydraulic fracturing is certainly not the culprit for introducing methane into domestic water supplies; if anything it would be the integrity of the wellbore during the drilling and casing operation. Routine well bore testing can identify leaks in the casing of a well bore and the problem can be mitigated if in fact they occur.

While we are on the subject, let’s clear up another misunderstanding: water contamination caused by a defective well is very different from a situation where there are background levels of methane present in the general area before gas drilling occurred.

More complex analysis is necessary in this case to determine if the gas originated from the deep formations of the Marcellus or from shallow, naturally-occurring gas which is not associated with drilling. In this case, pre-drill water sampling and/or local knowledge of pre-existing methane in the water assists in determining whether drilling influenced water quality.

Lessons learned:

  1. Science and the “need to be first” mentality of today’s media sometimes do not mix.  Determining migration pathways of gas is complex stuff and the Bloomberg story ignores the more complicated scientific evidence instead preferring to rely on an incomplete understanding of the data.
  2. The Bloomberg reporter incorrectly deduced that the methane migration is from hydraulic fracturing in the area.  Neither the Duke professors nor state regulators have stated this claim. So let’s leave “fracking” out of this – and remember that the EPA has already tested the water in Dimock and announced in July 2012 that it meets all federal drinking water standards.
  3. The anti-fracking opponents have conducted exhaustive studies throughout the nation in an effort to find the ‘smoking gun’ in order to stop hydraulic fracturing. During this process tens of thousands of wells have been successfully drilled and completed using hydraulic fracturing without any major effect to the water quality. The anti-fracking opponents simply ignore these facts.

A Well Thought Out Conclusion

As always, Cabot will continue to study the data.  We are proud to be a leader in Pennsylvania’s Marcellus natural gas production generation and of our collaborative relationship with the local community, state regulators and investments in local projects.


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