When Oil and Water Mix: Understanding the Environmental Impacts of Fracking

Dan Soeder, director of the Energy Resources Initiative  at the South Dakota School of Mines & Technology, has co-authored the cover article titled “When oil and water mix: Understanding the environmental impacts of shale development,” in the recent issue of GSA Today, a magazine published by the Geological Society of America.

The article explores what is known and not known about the environmental risks of fracking with the intent of fostering informed discussions within the geoscience community on the topic of hydraulic fracturing, says Soeder. Soeder’s co-author is Douglas B. Kent of the United States Geological Survey.

In this paper, Soeder and Kent bridge the gap in consensus regarding fracking, providing current information about the environmental impacts of shale development. The article is open access and adheres to science and policy, presenting a complicated and controversial topic in a manner more easily understood by the lay person.

“Geoscientists from dinosaur experts to the people studying the surface of Mars are often asked by the public to weigh-in with their opinions on fracking. We wanted the broader geoscience community to be aware of what is known and not known about the impacts of this technology on air, water, ecosystems and human health.  A great deal has been learned in the past decade, but there are still critical unknowns where we don’t yet have answers,” Soeder says.

Development of shale gas and tight oil, or unconventional oil and gas (UOG), has dramatically increased domestic energy production in the United States and Canada.  UOG resources are typically developed through the use of hydraulic fracturing, which creates high-permeability flow paths into large volumes of tight rocks to provide a means for hydrocarbons to move to a wellbore. This process uses significant volumes of water, sand, and chemicals, raising concerns about risks to the environment and to human health.

In the article, Soeder and Kent address the various potential impacts of fracking and how those impacts are being addressed.  Risks to air include releases of methane, carbon dioxide, volatile organic compounds, and particulate matter. Water-resource risks include excessive withdrawals, stray gas in drinking-water aquifers, and surface spills of fluids or chemicals. Landscapes can be significantly altered by the infrastructure installed to support large drilling platforms and associated equipment. Exposure routes, fate and transport, and toxicology of chemicals used in the hydraulic fracturing process are poorly understood, as are the potential effects on terrestrial and aquatic ecosystems and human health.

Schematic diagram illustrating unconventional oil and gas (UOG) development activities relevant to research on human-health and environmental impacts (not to scale): well-pad construction (1); drilling (2); completion/stimulation (3, 4); production of natural gas (5) and oil (6) with well casings designed to protect drinking-water aquifers; ultimate closure (plug and abandon), illustrating legacy well with leaking casing (7); wastewater disposal (8); induced seismicity (9); landscape disturbance (10); and potential for transport pathways from deep to shallow formations (11). Also represented are water supply wells in shallow and deep aquifers (12). Photographs by Dan Soeder.