Hydraulic fracturing: Fracturing of rock at depth with fluid pressure. Hydraulic fracturing at depth may be accomplished by pumping water into a well at very high pressures. Under natural conditions, vapor pressure may rise high enough to cause fracturing in a process known as hydrothermal brecciation. (EIA Glossary)
EPA states on its website, Natural Gas Extraction - Hydraulic Fracturing, "some concerns associated with overall natural gas and shale gas extraction, including hydraulic fracturing, are already well known. These operations can result in a number of potential impacts to the environment, including:
FracFocus, managed by the Ground Water Protection Council and Interstate Oil and Gas Compact Commission, was created to provide the public access to reported chemicals used for hydraulic fracturing within their area. To help users put this information into perspective, the site also provides objective information on hydraulic fracturing, the chemicals used, the purposes they serve and the means by which groundwater is protected.
Don Stowers, editor of Oil & Gas Financial Journal, quoted from a report by Dr. Joseph Stanislaw, who states:
"The United States has become the number-one producer of natural gas in the world. This is due to combining horizontal drilling and hydraulic fracturing technologies, a combination that has been in widespread use for just four years – and that has allowed gas from shale formations to go from accounting for just 2% of America's natural gas production in 2001 to over 30% today."
Stowers writes, "There are numerous challenges to overcome to achieve energy independence, not the least of which is a perception among many in the public that the oil and gas industry is greedy, doesn't care about the environment, and doesn't have their interests at heart." Stowers, D. (2012) Technology driving U.S. energy revolution. Oil & Gas Financial Journal 9(7)
Carl T. Montgomery and Michael B. Smith report in the 2010 article Hydraulic Fracturing: History of an enduring technology from the Journal of Petroleum Technology that Stanolind Oil introduced hydraulic fracturing in 1949 after testing the 'Hydrafrac' process in 1947 in Grand County, Kansas. A patent was issued in 1949, with an exclusive license granted to the Halliburton Oil Well Cementing Company (Howco) to pump the new Hydrafrac process.
This National Geographic interactive feature shows the drilling technique used by some energy producers to unlock natural gas from shale rock.
Investigative journalists at ProPublica provide a graphic representation of the process.
Source: ProPublica, http://www.propublica.org/special/hydraulic-fracturing-national
The Energy Institute at the University of Texas Austin issued this 2012 report about the three principal shale gas areas of the U.S. - Barnett shale in Texas, the Haynesville shale in East Texas and Louisiana, and the Marcellus shale in several states in the eastern U.S. - covering four topics:
News Coverage & Public Perceptions of Hydraulic Fracturing
Environmental Impacts of Shale Gas Development
Regulation of Shale Gas Development
State Enforcement of Shale Gas Development Regulation