by Bob Shively, Enerdynamics President and Lead Instructor 

A major concern of the United States’ current fracking boom is if and how fracking is negatively impacting the environment[1].  One key concern is that fracking may contaminate drinking water since elevated levels of methane in drinking water has been noted in locations near fracking sites. But the science of figuring out exactly what’s going on takes time, and meanwhile energy companies continue their fracking operations in and around communities across the nation.

Data from studies on fracking sites and water contamination is just now coming in. Several scientists who initially started work at Duke and are now at various universities have been studying natural gas contamination of wells in Pennsylvania and Texas and recently published their findings in the Proceedings of the Natural Academy of Sciences[2].

The group’s conclusion? Well contamination is occurring through poor well completion techniques, not from the migration of natural gas from deep underground induced by hydraulic fracturing techniques. This is good news for the industry and for the environment, since this type of well contamination should be controllable through use of proper well completion processes.

What was studied?

The scientists looked at two questions:

• Are elevated levels of hydrocarbon gas in drinking-water aquifers near gas wells derived from natural or man-made sources?
• If gas contamination exists due to man-made activities, what is causing the contamination?

To answer these questions, the scientists used a technique called noble gas and hydrocarbon tracers, which allows them to track the source of hydrocarbon gas.

Were elevated levels due to human activities?

The scientists use the term “fugitive gas” to describe gas that migrated into drinking water sources from other locations due to human activities. They documented fugitive gases in eight clusters of domestic water wells in Pennsylvania and Texas. The Texas wells showed declining water quality over time indicating recent activities have caused the contamination.

What caused the contamination?

The scientists theorized that man-made contamination could occur due to multiple causes. For the eight cases of contamination they were able to identify the cause:

• Four cases were due to leaks through the annulus cement
• Three cases were due to leaks through the production casings
• One case was due to underground well failure

In no case was the mechanism of contamination gas migration induced by hydraulic fracturing deep underground.

What does this mean?

Certainly study is needed for more than just eight cases of contamination. But the data received to date suggests that energy companies and their regulators should focus on procedures and rules to ensure the integrity of the wells themselves rather than stopping fracking over concerns of migration of gas from deep underground. The scientists suggested that further work should evaluate whether large volumes of highly pressurized fluids used during fracking may affect the integrity of wells. If so, more steps may be required than simply improving well completion procedures.

References:

[1] For a discussion of fracking see: http://marketing.enerdynamics.com/Energy-Insider/2011/Q3NaturalGas.htm

[2] Available at: http://www.pnas.org/content/early/2014/09/12/1322107111.full.pdf+html