The economic opportunities presented by vast reserves of natural gas in regions of Marcellus shale are accompanied by complex, controversial questions about the potential environmental impact of hydraulic fracturing extraction methods. A pair of West Virginia University researchers is answering one of those questions with the support of a $27,500 grant from the USDA Forest service.
Nicolas Zegre, a forest hydrologist in the Davis College of Agriculture, Natural Resources and Design, and Shikha Sharma, a geochemist in WVU’s Eberly College of Arts and Sciences, have joined forces to compare methane levels in well water before and after hydraulic fracturing activity. Hydraulic fracturing, or hydrofracking, is the process of pumping a pressurized fluid underground to break up—fracture—rocks layers to more easily release gas.
The researchers will also try to pinpoint the source of that methane, as well as a radium isotope that degrades into radon gas.
Zegre and Sharma are studying water pumped from six wells that provide water to Forest Service campgrounds near Sutton Lake in the Monongahela National Forest. This will allow them to establish a baseline of methane levels in the wells prior to future hydrofracking activity, which is expected to take place in the next year. The researchers will repeat their evaluation of the well water after hydrofracking takes place.
“High dissolved methane levels alone cannot be indicative of methane release associated with hydrofracking” said Sharma. As part of her ongoing study for the United States Geological Survey, Sharma has found that high concentrations of dissolved methane can be found in groundwater wells where no hydrofracking has taken place.
She and a graduate student, Michon Mulder of Vinton, Ia., who is pursuing a master’s degree in geology, have been trying to understand the sources of dissolved methane in samples collected from more than 40 groundwater wells in the Monongahela River watershed. All of these samples were collected from areas where there is no current drilling activity. According to Sharma, methane levels in those samples have varied significantly.
In the area of Marcellus shale development in West Virginia, methane in groundwater can originate from several sources. The methane is either thermogenic – produced at great depth with heat – or biogenic – created by the decomposition of organic matter.
“Methane can be formed by microbial activity in shallow aquifers, coal seams, deep coal mines, storage gas fields, and abandoned oil and gas fields,” Sharma said. Each of these sources of methane is likely to have unique carbon and hydrogen signatures, and can be used to fingerprint sources of methane.
“This approach allows us to understand what the source of this methane is,” Zegre said. “By understanding the difference, we have a sense of where the methane is coming from.”
“This new USDA project will help us add on new data points to this study,” Sharma said. “Further, in this study Nicolas will develop a more robust hydrological model for the study sites which would eventually help us in better interpreting the methane’s fingerprint.”
To define that fingerprint, Sharma is looking at concentrations and stable isotope signatures of carbon and radium isotopes of dissolved gases in the well water, while Zegre is studying the water isotopes overall.
Groundwater wells are generally dug to a maximum depth of about 400 feet, while wells associated with hydrofracking range between 5,000 and 7,000 feet in depth. Sharma and Zegre’s work will allow them to pinpoint hydrological connections, both before and after drilling into the region’s Marcellus shale.
Past research on hydrofracking-related methane levels in well water sparked controversy, in part because of questions about the baseline data available on pre-existing methane levels for comparison. This study offers an opportunity to both establish that baseline and to study the impact of hydrofracking on well water quality.
It also provides a unique opportunity for another WVU graduate student. Patrick Eisenhauer, of Jersey Shore, Pa., earned a B.S. in wood science and technology from the University in May. Undergraduate work for Muncy Hardwoods introduced him to the process of site preparation for Marcellus shale drilling. That sparked his scholarly interest in the subject, which led him to WVU’s master’s program in forest hydrology.
Eisenhauer describes the opportunity to work with the researchers as “absolutely amazing. I’m a very lucky individual to be working with them.”
Sharma is part of WVU’s ADVANCE and WiSE initiative to encourage and mentor women in science, technology, engineering and mathematics. Zegre’s research on the causes of flooding in West Virginia earned him a 2011 Ralph E. Powe Jr. Faculty Enhancement Award from Oak Ridge Associated Universities. Zegre has also received funding from the National Science Foundation to study the impact of surface mining on stream flow and storm water patterns.
In addition to his work on the Forest Service project, Eisenhauer is creating an index that gauges the availability of surface water and estimates any fluctuations that occur in relation to Marcellus shale drilling activity. To do this, he will synthesize county data from throughout the Marcellus shale region – more than 50 counties in West Virginia, New York, Ohio and Pennsylvania.
CONTACT: David Welsh, Davis College of Agriculture, Natural Resources and Design
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