Poor Well Construction Is The Culprit

The iconic image of shale gas development is the flaming faucet featured in Josh Fox’s recent movie, Gasland.  Inquiring minds want to know: “how does methane get into a water faucet, and is hydraulic fracturing of shale to blame?”  A Duke University study released this week sheds light on these important questions.

The study, performed by three researchers affiliated with Duke University’s Biology Department and Nicholas School of the Environment, examined 60 drinking water wells in northeastern Pennsylvania and southern New York, the northern tier of the geological formation known as the Marcellus Shale, ground zero for aggressive shale gas development in the eastern United States.  And sure enough, methane concentrations were detected in 51 of the 60 wells, with substantially higher concentrations of methane found in drinking water wells closest to active natural gas production sites.  While there are numerous instances of methane migrating into drinking water supplies through naturally occurring fissures, even in the absence of gas drilling, this study makes a pretty compelling case that natural gas production can create a problem where none ever existed, or certainly make an existing problem worse.

But, on the question of whether hydraulic fracturing is to blame, the evidence is less compelling.  Indeed, the fact that methane was found in water wells, but the chemicals used to fracture the shale were not, suggests that fracturing may have had nothing to do with the unwanted migration.  The culprit, it would seem, are not fissures created by the fracturing of the shale, but rather poor well construction – specifically, failures in the cement casing surrounding a well – which enable the natural gas to migrate into the water table as it moves its way up the well to the surface.  The authors have noted that “leaky casings” are the most likely cause of problems.

Poor well construction is a problem that can occur anywhere, whether production is aided by hydraulic fracturing or not.  For all of the attention Gasland’s flaming faucet has brought to the hydraulic fracturing debate, this study points our attention to the role that better well construction and design practices can play in reducing the very real problem of methane contamination of well water.

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    Associate Vice President & Chief Counsel of the US Energy and Climate Program
    Mark Brownstein is the Associate Vice President & Chief Counsel of the US Energy and Climate Program at Environmental Defense Fund (EDF), and he leads EDF’s natural gas efforts.

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