Using pressurized fluids to crack rocks to extract natural fossil fuels is called hydraulic fracturing, or fracking. The process is used to extract oil or gas from impermeable or tight geologic formations, such as shale rock formations and tight sands. The pressurized fluids, including water and chemical additives, open or enlarge fractures in the rock. Sand or other material is then pumped into the fractures to keep the fractures open. The water and chemical additives are returned to the surface and gas flows from pores and fractures in the rock into an existing well for extraction.
While the process has been used since the 1940s in the US to increase production from oil wells, it is now increasingly being used to extract gas from shale formations. Concerns are rising about the threats to groundwater and public health from the chemicals in the fluids. In the United States, there have been reported instances of groundwater contamination and illnesses from the fracking and the US Environmental Protection Agency (EPA) is currently carry out a research project to determine the nature and scope of any risks associated with fracturing.
Some further ideas to explore on Hydraulic Fracturing:
See if you can find any data or information on what chemicals are used by the gas extraction industry in fracking and what risks there are from those chemicals.
If you cannot find information or data, what issues does that create for assessing the impacts from fracking?
“Hydraulic Fracturing,” US EPA at www.epa.gov/safewater/uic/wells_hydrofrac.html
Mark Zoback Saya Kitasei Brad Copithorne, Addressing the Environmental Risks from Shale Gas Development, Worldwatch Institute, July 2010 www.worldwatch.org/node/6421
“Philadelphia seeks ban on hydraulic fracturing,” Reuters/ENN News, March 26, 2010 www.enn.com/top_stories/article/41147
Update: 27 Feb 2011
“Regulation Lax as Gas Wells’ Tainted Water Hits Rivers,” The New York Times, 27 February 2011. www.nytimes.com/2011/02/27/us/27gas.html?_r=1&ref=us
Update: 1 Nov 2011
Osborn, SG, A Vengosh, NR Warner, RB Jackson, “Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing.” Proceedings of the National Academy of Sciences (May 17, 2011). www.pnas.org/content/108/20/8172
Robert B. Jackson, Brooks Rainey Pearson, Stephen G. Osborn,
Nathaniel R. Warner, Avner Vengosh, Research and Policy Recommendations for Hydraulic Fracturing and Shale-Gas Extraction (Duke University)