Hydraulic fracturing of shale formations to extract
natural gas has no direct connection to reports of groundwater contamination,
based on evidence reviewed in a study released by the Energy Institute at The
University of Texas at Austin.
The study, released at the annual meeting of the
American Association for the Advancement of Science (AAAS) in Vancouver,
British Columbia, found that many problems ascribed to hydraulic fracturing are
related to processes common to all oil and gas drilling operations, such as
casing failures or poor cement jobs. University researchers also concluded that
many reports of contamination can be traced to above-ground spills or other
mishandling of wastewater produced from shale gas drilling, rather than from
hydraulic fracturing per se, said Charles "Chip" Groat, an Energy
Institute associate director who led the project. "These problems are not
unique to hydraulic fracturing," he said. The research team examined
evidence contained in reports of groundwater contamination attributed to
hydraulic fracturing in three prominent shale plays — the Barnett Shale in
North Texas; the Marcellus Shale in Pennsylvania, New York and portions of
Appalachia; and the Haynesville Shale in western Louisiana and northeast Texas.
The report identifies regulations related to shale gas development and
evaluates individual states' capacity to enforce existing regulations. In
addition, university researchers analyzed public perceptions of hydraulic
fracturing, as derived from popular media, scientific literature and online
surveys. "Our goal was to provide policymakers a foundation for developing
sensible regulations that ensure responsible shale gas development," Groat
said. "What we've tried to do is separate fact from fiction." Faculty
members from across The University of Texas at Austin campus participated in
the research, which the Energy Institute funded. The Environmental Defense Fund
also assisted in developing the scope of work and methodology for the study. Groat
said researchers will supplement the study released Thursday with an
examination of reports relating to atmospheric emissions and seismic activity
attributed to hydraulic fracturing, which have emerged as significant issues of
concern in recent months. Hydraulic fracturing involves the high-pressure
injection of water, sand and chemicals into a shale bed, which causes the rock
to shatter, releasing natural gas. The practice has been in use for decades but
has come under scrutiny in recent years from environmentalists and others who
fear it poses a threat to public health. Other findings from the Energy
Institute study include: Natural gas found in water wells within some shale gas
areas (e.g., Marcellus) can be traced to natural sources and probably was
present before the onset of shale gas operations. Although some states have
been proactive in overseeing shale gas development, most regulations were
written before the widespread use of hydraulic fracturing. Media coverage of
hydraulic fracturing is decidedly negative, and few news reports mention
scientific research related to the practice. Overall, surface spills of
fracturing fluids pose greater risks to groundwater sources than from hydraulic
fracturing itself. The lack of baseline studies in areas of shale gas
development makes it difficult to evaluate the long-term, cumulative effects
and risks associated with hydraulic fracturing. Groat also provided an overview
of two other Energy Institute initiatives related to the use of hydraulic
fracturing in shale gas development.
The first project, which will commence in April, is
a detailed case study focusing on claims of groundwater contamination in North
Texas' Barnett Shale. The research will entail an examination of various
aspects of shale gas development, including site preparation, drilling,
production, and handling and disposal of flow-back water. Researchers also will
identify and document activities unrelated to shale gas development that have
resulted in water contamination. It will also assess the quantity of fresh
groundwater used in shale gas development and evaluate ways to reduce the
amount.
A second
project, currently under development, would include a field and laboratory
investigation of whether hydrological connectivity exists between water in the
units above and below the shale unit being fractured as a result of the
fracturing process. As envisioned, the project calls for university researchers
to conduct field sampling of hydraulic fracturing fluid, flow-back water,
produced water, and water from aquifers and other geologic units within the
Barnett Shale.
Source: www.eponline.com
February 27 2012.