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Hydraulic fracturing is the propagation of fractures in a rock layer caused by the presence of a pressurized fluid. Hydraulic fractures may form naturally, as in the case of veins or dikes, or may be man-made in order to release petroleum, natural gas, coal seam gas, or other substances for extraction, where the technique is often called fracking or hydrofracking. This type of fracturing, known colloquially as a frack job (or frac job), is done from a wellbore drilled into reservoir rock formations. The energy from the injection of a highly-pressurized fracking fluid, creates new channels in the rock which can increase the extraction rates and ultimate recovery of fossil fuels. The fracture width is typically maintained after the injection by introducing a proppant into the injected fluid. Proppant is a material, such as grains of sand, ceramic, or other particulates, that prevent the fractures from closing when the injection is stopped.

The practice of hydraulic fracturing has come under scrutiny internationally due to concerns about the environmental impact, health and safety, and has been suspended or banned in some countries.

Mechanics

Fracturing in rocks at depth is suppressed by the confining pressure, particularly in the case of tensile (Mode 1) fractures which require the walls of the fracture to move apart. Hydraulic fracturing occurs when the effective stress is reduced sufficiently by an increase in the pressure of fluids in the rock such that the minimum principal stress becomes tensile and exceeds the tensile strength of the material. Fractures formed in this way will typically be orientated perpendicular to the minimum principal stress and for this reason, induced hydraulic fractures in wellbores are sometimes used to determine stress orientations. In natural examples, such as dikes or vein-filled fractures, their orientations can be used to infer past stress states .

Natural examples

Rocks often contain evidence of past hydraulic fracturing events, where fluids have passed through tensile fractures.

Veins

Most vein systems are a result of repeated hydraulic fracturing during periods of relatively high pore fluid pressure. This is particularly clear in the case of 'crack-seal' veins, where the vein material can be seen to have been added in a series of discrete fracturing events, with extra vein material deposited on each occasion. One mechanism to explain such examples of long-lasting repeated fracturing, is the effects of seismic activity, in which the stress levels rise and fall episodically and large volumes of fluid may be expelled from fluid-filled fractures during earthquakes, a process referred to as 'seismic pumping'.

Dikes

High-level minor intrusions such as dikes propagate through the crust in the form of fluid-filled cracks, although in this case the fluid is magma. In sedimentary rocks with a significant water content the fluid at the propagating fracture tip will be steam.

Induced hydraulic fracturing

The technique of hydraulic fracturing is used to increase or restore the rate at which fluids, such as oil, water, or natural gas can be produced from subterranean natural reservoirs. Reservoirs are typically porous sandstones, limestones or dolomite rocks, but also include 'unconventional reservoirs' such as shale rock or coal beds. Hydraulic fracturing enables the production of natural gas and oil from rock formations deep below the earth's surface (generally 5,000–20,000 feet or 1,500–6,100 m). At such depth, there may not be sufficient porosity, permeability or reservoir pressure to allow natural gas and oil to flow from the rock into the wellbore at economic rates. Thus, creating conductive fractures in the rock is essential to extract gas from shale reservoirs because of the extremely low natural permeability of shale, which is measured in the microdarcy to nanodarcy range. Fractures provide a conductive path connecting a larger area of the reservoir to the well, thereby increasing the area from which natural gas and liquids can be recovered from the targeted formation.

While the main industrial use of hydraulic fracturing is in stimulating production from oil and gas wells, hydraulic fracturing is also applied to:

• Stimulating groundwater wells
• Preconditioning rock for caving or inducing rock to cave in mining
• As a means of enhancing waste remediation processes, usually hydrocarbon waste or spills
• Dispose of waste by injection into deep rock formations
• As a method to measure the stress in the earth
• For heat extraction to produce electricity in an Enhanced Geothermal System

Method

A hydraulic fracture is formed by pumping the fracturing fluid into the wellbore at a rate sufficient to increase pressure downhole to exceed that of the fracture gradient of the rock. The rock cracks and the fracture fluid continues farther into the rock, extending the crack still farther, and so on. To keep this fracture open after the injection stops, a solid proppant, commonly a sieved round sand, is added to the fluid. The propped fracture is permeable enough to allow the flow of formation fluids to the well. Formation fluids include gas, oil, salt water, fresh water and fluids introduced to the formation during completion of the well during fracturing.

The location of one or more fractures along the length of the borehole is strictly controlled by various different methods which create or seal-off holes in the side of the wellbore. Typically, hydraulic fracturing is performed in cased wellbores and the zones to be fractured are accessed by perforating the casing at those locations.

Well types

While hydraulic fracturing is many times performed in vertical wells, today it is also performed in horizontal wells. Horizontal drilling involves wellbores where the terminal drillhole is completed as a 'lateral' that extends parallel with the rock layer containing the substance to be extracted. For example, laterals extend 1,500 to 5,000 feet in the Barnett Shale basin in Texas, and up to 10,000 feet in the Bakken formation in North Dakota. In contrast, a vertical well only accesses the thickness of the rock layer, typically 50–300 feet. Horizontal drilling also reduces surface disruptions as fewer wells are required. Drilling usually induces damage to the pore space at the wellbore wall, reducing the permeability at and near the wellbore. This reduces flow into the borehole from the surrounding rock formation, and partially seals off the borehole from the surrounding rock. Hydraulic fracturing can be used to restore permeability.

Hydraulic fracturing is commonly applied to wells drilled in low permeability reservoir rock. An estimated 90 percent of the natural gas wells in the United States use hydraulic fracturing to produce gas at economic rates.

Fracturing

The fluid injected into the rock is typically a slurry of water, proppants, and chemical additives. Additionally, gels, foams, and compressed gases, including nitrogen, carbon dioxide and air can be injected. Various types of proppant include silica sand, resin-coated sand, and man-made ceramics. These vary depending on the type of permeability or grain strength needed. Sand containing naturally radioactive minerals is sometimes used so that the fracture trace along the wellbore can be measured. Chemical additives are applied to tailor the injected material to the specific geological situation, protect the well, and improve its operation, though the injected fluid is approximately 98-99.5% percent water, varying slightly based on the type of well. The composition of injected fluid is sometimes changed as the fracturing job proceeds. Often, acid is initially used to scour the perforations and clean up the near-wellbore area. Then proppants are used with a gradual increase in their size and/or density. At the end of the job the well is commonly flushed with water (sometimes blended with a friction reducing chemical) under pressure. Injected fluid is to some degree recovered and is managed by several methods, such as underground injection control, treatment and discharge, recycling, or temporary storage in pits or containers while new technology is being developed to better handle wastewater and improve reusability. Although the concentrations of the chemical additives are very low, the recovered fluid may be harmful due in part to hydrocarbons picked up from the formation.

Hydraulic fracturing equipment used in oil and natural gas fields usually consists of a slurry blender, one or more high pressure, high volume fracturing pumps (typically powerful triplex, or quintiplex pumps) and a monitoring unit. Associated equipment includes fracturing tanks, one or more units for storage and handling of proppant, high pressure treating iron, a chemical additive unit (used to accurately monitor chemical addition), low pressure flexible hoses, and many gauges and meters for flow rate, fluid density, and treating pressure. Fracturing equipment operates over a range of pressures and injection rates, and can reach up to 100 MPa (15,000 psi) and 265 L/s (100 barrels per minute).

Fracture monitoring

Measurements of the pressure and rate during the growth of a hydraulic fracture, as well as knowing the properties of the fluid and proppant being injected into the well provides the most common and simplest method of monitoring a hydraulic fracture treatment. This data, along with knowledge of the underground geology can be used to model information such as length, width and conductivity of a propped fracture.

For more advanced applications, Microseismic monitoring is sometimes used to estimate the size and orientation of hydraulically induced fractures. Microseismic activity is measured by placing an array of geophones in a nearby wellbore. By mapping the location of any small seismic events associated with the growing hydraulic fracture, the approximate geometry of the fracture is inferred. Tiltmeter arrays, deployed on the surface or down a well, provide another technology for monitoring the strains produced by hydraulic fracturing.

Emission of gases displaced by hydraulic fracturing into the atmosphere may be detected via atmospheric gas monitoring, and can be quantified directly via the eddy covariance flux measurements.

Horizontal completions

Since the early 2000s, advances in drilling and completion technology has made drilling horizontal wellbores much more economical. Horizontal wellbores allow for far greater exposure to a formation than a conventional vertical wellbore. This is particularly useful in shale oil and gas formations which do not have sufficient permeability to produce economically with a vertical well. Such wells when drilled onshore are now usually hydraulically fractured many times, especially in North America. The type of wellbore completion used will affect how many times the formation is fractured, and at what locations along the horizontal section of the wellbore.

In North America, tight reservoirs such as the Bakken, Barnett Shale, Montney and Haynesville Shale are drilled, completed and fractured using this method. The method by which the fractures are placed along the wellbore is most commonly achieved by one of two methods, known as 'plug and perf' and 'sliding sleeve'.

The wellbore for a plug and perf job is generally composed of standard joints of steel casing, either cemented or uncemented, which is set in place at the conclusion of the drilling process. Once the drilling rig has been removed, a wireline truck is used to perforate near the end of the well, following which a fractuing job is pumped (commonly called a stage). Once the stage is finished, the wireline truck will set a plug in the well to temporarily seal off the that section, and then perforate the next section of the wellbore. Another stage is then pumped, and the process is repeated as necessary along the entire length of the horizontal part of the wellbore.

The wellbore for the sliding sleeve technique is different in that the sliding sleeves are included at set spacings in the steel casing at the time it is set in place. The sliding sleeves are usually all closed at this time. When the well is ready to be fractured, using one of several activation techniques, the bottom sliding sleeve is opened and the first stage gets pumped. Once finished, the next sleeve is opened which concurrently isolates the first stage, and the process repeats. For the sliding sleeve method, wireline is usually not required.

These completion techniques may allow for more than 30 stages to be pumped into the horizontal section of a single well if required, which is far more than would typically be pumped into a vertical well.

Terminology

Fracture Gradient

The pressure to fracture the formation at a particular depth divided by the depth. A fracture gradient of 18 kPa/m (0.8 psi/foot) implies that at a depth of 3 km (10,000 feet) a pressure of 54 MPa (8,000 psi) will extend a hydraulic fracture.

ISIP — Initial Shut In Pressure

The pressure measured immediately after injection stops. The ISIP provides a measure of the pressure in the fracture at the wellbore by removing contributions from fluid friction.

Leakoff

Loss of fracturing fluid from the fracture channel into the surrounding permeable rock.

Fracturing fluid

The fluid used during a hydraulic fracture treatment of oil, gas, or water wells. The fracturing fluid has two major functions:

1. Open and extend the fracture.
2. Transport the proppant along the fracture length.

Proppant

Suspended particles in the fracturing fluid that are used to hold fractures open after a hydraulic fracturing treatment, thus producing a conductive pathway that fluids can easily flow along. Naturally occurring sand grains or artificial ceramic material are common proppants used.

Concise slang

"Fracing" (sometimes spelled "fracking" primarily in media) is a shortened version of fracturing.

Environmental concerns

Environmental concerns with hydraulic fracturing include the potential contamination of ground water, risks to air quality, the potential migration of gases and hydraulic fracturing chemicals to the surface, the potential mishandling of waste, and the health effects of these. A 2004 study by the Environmental Protection Agency (EPA) concluded that the injection of hydraulic fracturing fluids into CBM wells posed minimal threat to underground drinking water sources. This study has been criticised for only focusing on the injection of fracking fluids, while ignoring other aspects of the process such as disposal of fluids, and environmental concerns such as water quality, fish kills and acid burns; the study was also concluded before public complaints of contamination started emerging. Largely on the basis of this study, in 2005 hydraulic fracturing was exempted by US Congress from any regulation under the Safe Drinking Water Act.

With the explosive growth of natural gas wells in the US, researcher Valerie Brown predicted in 2007 that "public exposure to the many chemicals involved in energy development is expected to increase over the next few years, with uncertain consequences." As development of natural gas wells in the U.S. since the year 2000 has increased, so too have claims by private well owners of water contamination. This has prompted EPA and others to re-visit the topic.

While the EPA recognizes the potential for contamination of water by hydraulic fracturing, EPA Administrator Lisa Jackson testified in a Senate Hearing Committee "I'm not aware of any proven case where the fracking process itself has affected water...". There are, however, documented incidents of contamination. In 2006 drilling fluids and methane were detected leaking from the ground near a gas well in Clark, Wyoming; 8 million cubic feet of methane were eventually released, and shallow groundwater was found to be contaminated. In the town of Dimock, Pennsylvania, 13 water wells were contaminated with methane (one of them blew up), and the gas company, Cabot Oil & Gas, had to financially compensate residents and construct a pipeline to bring in clean water; the company continued to deny, however, that any "of the issues in Dimock have anything to do with hydraulic fracturing".

Air emissions and pollution

One group of emissions associated with natural gas development and production, are the emissions associated with combustion. These emissions include particulate matter, nitrogen oxides, sulfur oxide, carbon dioxide and carbon monoxide. Another group of emissions that are routinely vented into the atmosphere are those linked with natural gas itself, which is composed of methane, ethane, liquid condensate, and volatile organic compounds (VOCs). The VOCs that are especially impactful on health are benzene, toluene, ethyl benzene, and xylene (referred to as a group, called BTEX). Health effects of exposure to these chemicals include neurological problems, birth defects, and cancer.

VOCs, including BTEX, mixed with nitrogen oxides from combustion and combined with sunlight can lead to ozone formation. Ozone has been shown to impact lung function, increase respiratory illness, and is particularly dangerous to lung development in children. In 2008, measured ambient concentrations in the rural Sublette County Wyoming where ranching and natural gas are the main industries were frequently above the National Ambient Air Quality Standards (NAAQS) of 75ppb and have been recorded as high as 125 ppb.

Groundwater contamination

A Duke University study published in Proceedings of the National Academy of Sciences in 2011 examined methane in groundwater in Pennsylvania and New York states overlying the Marcellus Shale and the Utica Shale. It determined that groundwater tended to contain much higher concentrations of methane near fracking wells, with potential explosion hazard; the methane's isotopic signatures and other geochemical indicators were consistent with it originating in the fracked deep shale formations, rather than any other source. Complaints from a few residents on water quality in a developed natural gas field prompted an EPA groundwater investigation in Wyoming. The EPA reported detections of methane and other chemicals such as phthalates in private water wells.

In Pavillion, Wyoming, the EPA discovered traces of methane and foaming agents in several water wells near a gas rig, though it suggested these chemicals might have come from cleaning products. In DISH, Texas, elevated levels of disulphides, benzene, xylenes and naphthalene have been detected in the air, alongside numerous local complaints of headaches, diarrhea, nosebleeds, dizziness, muscle spasms and other problems.

Groundwater contamination doesn't come directly from injecting fracking chemicals deep into Shale rock formations well below water aquifers but from waste water evaporation ponds and poorly constructed pipelines taking the waste water and chemicals to processing facilities. The evaporation ponds allow the volatile chemicals in the waste water to evaporate into the atmosphere and when it rains these ponds tend to overflow and the runoff eventually makes its way into groundwater systems. Another way groundwater gets contaminated relating to fracking is from the temporary, and poorly constructed pipelines to transport the waste water to water treatment plants. These pipelines can leak and in come cases break in a section all together allowing the waste water and fracking chemicals to flow into groundwater systems. The transportation by trucks and storage of fracking chemicals allows for groundwater to become contaminated when accidents happen during transportation to the fracking site or to its disposal destination.

Epidemiological studies that might confirm or rule out any connection between these complaints and fracking are virtually non-existent. Individuals "smell things that don't make them feel well, but we know nothing about cause-and-effect relationships in these cases." In Garfield County, Colorado, another area with a high concentration of drilling rigs, volatile organic compound emissions increased 30% between 2004 and 2006; during the same period there was a rash of health complaints from local residents. The health effects of VOCs are largely unquantified, so any causal relationship is difficult to ascertain; however, some of these chemicals are suspected carcinogens and neurotoxins. Investigators from the Colorado School of Public Health performed a study in Garfield regarding potential adverse health effects, and concluded that residents near gas wells might suffer chemical exposures, accidents from industry operations, and psychological impacts such as depression, anxiety and stress. This study (the only one of its kind to date) was never published, owing to disagreements between community members and the drilling company over the study's methods.

In 2010 the film Gasland premiered at the Sundance Film Festival. The filmmaker claims that chemicals including toxins, known carcinogens, and heavy metals polluted the ground water near well sites in Pennsylvania, Wyoming, and Colorado.

A 2011 report by the Massachusetts Institute of Technology addressed groundwater contamination, noting "There has been concern that these fractures can also penetrate shallow freshwater zones and contaminate them with fracturing fluid, but there is no evidence that this is occurring. There is, however, evidence of natural gas migration into freshwater zones in some areas, most likely as a result of substandard well completion practices by a few operators. There are additional environmental challenges in the area of water management, particularly the effective disposal of fracture fluids". This study encourages the use of industry best practices to prevent such events from recurring.

Directed by Congress, the U.S. EPA announced in March 2010 that it will examine claims of water pollution related to hydraulic fracturing.

Radioactive contamination

The New York Times has reported radiation in hydraulic fracturing wastewater released into rivers in Pennsylvania. According to a Times report in February 2011, wastewater at 116 of 179 deep gas wells in Pennsylvania "contained high levels of radiation," but its effect on public drinking water supplies is unknown because water suppliers are required to conduct tests of radiation "only sporadically". The Times stated "never-reported studies" by the EPA and a "confidential study by the drilling industry" concluded that radioactivity in drilling waste cannot be fully diluted in rivers and other waterways. Despite this, as of early 2011 federal and state regulators did not require sewage treatment plants that accept drilling waste (which is mostly water) to test for radioactivity. In Pennsylvania, where the drilling boom began in 2008, most drinking-water intake plants downstream from those sewage treatment plants have not tested for radioactivity since before 2006.

The New York Post stated that the Pennsylvania Department of Environmental Protection reported that all samples it took from seven rivers in November and December 2010 "showed levels at or below the normal naturally occurring background levels of radioactivity", and "below the federal drinking water standard for Radium 226 and 228.". However the samples taken by the state at at least one river, (the Monongahela, a source of drinking water for parts of Pittsburgh), were taken upstream from the sewage treatment plants accepting drilling waste water. Furthermore, the New York Times has implicated the DEP in industry-friendly inactivity, such as only making a "request — not a regulation" of gas companies to handle their own flowback waste rather than sending them to public water treatment facilities.

Chemicals used in fracturing

Water is by far the largest component of fracking fluids. The initial drilling operation itself may consume from 65,000 gallons to 600,000 gallons of fracking fluids. Over its lifetime an average well will require up to an additional 5 million gallons of water for the initial fracking operation and possible restimulation frac jobs.

Chemical additives used in fracturing fluids typically make up less than 2% by weight of the total fluid. Over the life of a typical well, this may amount to 100,000 gallons of chemical additives. They are biocides, surfactants, adjusting viscosity, and emulsifiers. Many are used in household products such as cosmetics, lotions, soaps, detergents, furniture polishes, floor waxes, and paints. Some are also used in food products. A list of the chemicals that have been used was published in a U.S. House of Representatives Report. Some of the chemicals pose no known health hazards, some others are known carcinogens, some are toxic, some are neurotoxins. For example: benzene (causes cancer, bone marrow failure), lead (damages the nervous system and causes brain disorders), ethylene glycol (antifreeze, causes death), methanol (highly toxic), boric acid (kidney damage, death), 2-butoxyethanol (causes hemolysis).

The 2011 US House of Representatives investigative report on the chemicals used in hydraulic fracturing shows that of the 750 compounds in hydraulic fracturing products “ore than 650 of these products contained chemicals that are known or possible human carcinogens, regulated under the Safe Drinking Water Act, or listed as hazardous air pollutants” (12). The report also shows that between 2005 and 2009 279 products (93.6 million gallons-not including water) had at least one component listed as “proprietary” or “trade secret” on their Occupational Safety and Health Administration (OSHA) required Material Safety Data Sheet (MSDS).

The MSDS is a list of chemical components in the products of chemical manufacturers, and according to OSHA, a manufacturer may withhold information designated as “proprietary” from this sheet. When asked to reveal the proprietary components, most companies participating in the investigation were unable to do so, leading the committee to surmise these “companies are injecting fluids containing unknown chemicals about which they may have limited understanding of the potential risks posed to human health and the environment” (12). Third-party laboratories are performing analysis on soil, air, and water near the fracturing sites to measure the level of contamination by each of the chemicals. Each state has a contact person in charge of such regulation. A map of these contact people can be found at FracFocus.org as well.

Another study in 2011, titled “Natural Gas Operations from a Public Health Perspective” and published in Human and Ecological Risk Assessment: An International Journal identified 632 chemicals used in natural gas operations. Only 353 of these are well-described in the scientific literature; and of these, more than 75% could affect skin, eyes, respiratory and gastrointestinal systems; roughly 40-50% could affect the brain and nervous, immune and cardiovascular systems and the kidneys; 37% could affect the endocrine system; and 25% were carcinogens and mutagens. The study indicated possible long-term health effects that might not appear immediately. The study recommended full disclosure of all products used, along with extensive air and water monitoring near natural gas operations; it also recommended that fracking's exemption from regulation under the US Safe Drinking Water Act be rescinded.

Earthquakes

A report in the UK concluded that fracking was the likely cause of some small earth tremors that happened during shale gas drilling. In addition the United States Geological Survey (USGS) reports that "Earthquakes induced by human activity have been documented in a few locations" in the United States, Japan, and Canada; "the cause was injection of fluids into deep wells for waste disposal and secondary recovery of oil, and the use of reservoirs for water supplies." The disposal and injection wells referenced are regulated under the Safe Drinking Water Act and UIC laws and are not wells where hydraulic fracturing is generally performed.

Greenhouse gas emissions

The use of natural gas rather than oil or coal is sometimes touted as a way of alleviating global warming: natural gas burns more cleanly, and gas power stations can produce up to 50% less greenhouse gases than coal stations. However, an analysis of the well-to-consumer lifecycle of fracked natural gas concluded that 3.6–7.9% of the methane produced by a well will be leaked into the atmosphere during the well's lifetime. Because methane is such a potent greenhouse gas, this means that over short timescales, shale gas is actually worse than coal or oil. Methane gradually breaks down in the atmosphere, forming carbon dioxide, so that over very long periods it is no more problematic than carbon dioxide; in the meantime, even if shale gas is burnt in efficient gas power stations, its greenhouse-gas footprint is still worse than coal or oil for timescales of less than fifty years.

Public relations

The considerable opposition against fracking activities in local townships has led companies to adopt a variety of public relations measures to assuage fears about fracking, including the admitted use of "mil­i­tary tac­tics to counter drilling oppo­nents". At a conference where public relations measures were discussed, a senior executive at Anadarko Petroleum was recorded on tape saying, "Download the US Army / Marine Corps Counterinsurgency Manual, because we are dealing with an insurgency", while referring to fracking opponents. Matt Pitzarella, spokesman for the most important fracking company in Pennsylvania, Range Resources, also told other conference attendees that Range employed psychological warfare operations veterans. According to Pitzarella, the experience learnt in the Middle East has been valuable to Range Resources in Pennsylvania, when dealing with emotionally-charged township meetings and advising townships on zoning and local ordinances dealing with fracking.

Hydraulic fracturing by country

Hydraulic fracturing has become a contentious environmental and health issue with France banning the practice and a moratorium in place in New South Wales (Australia), Karoo basin (South Africa), Quebec (Canada), and some of the states of the US.

Australia

Up until the mid 2000s, hydraulic fracturing was generally limited to conventional oil and gas wells in the Cooper Basin and limited to one, two or sometimes zero ongoing fracturing operations. However more recently, it has spread and grown in Queensland as coal seam gas drilling and production in the Surat and Bowen basins has rapidly increased. However the vast majority of coal seam gas wells have not been hydraulically fractured as the wells presently being drilled are in coal seams that have good natural permeability.

On 21 February 2011, the ABC's investigative journalism program Four Corners aired a program showing incidents of wellhead gas leaks (unrelated to hydraulic fracturing) and alleged aquifer contamination near Chinchilla, Queensland at wells owned by QGC, some of which had been hydraulically fractured.

There is currently a moratorium in place on the practice of hydraulic fracturing in the state of New South Wales.. The moratorium will not affect exploration, drilling core holes and getting core samples. The NSW Government's restrictions on hydraulic fracturing apply to new licences only. The NSW Government has banned BTEX chemicals as additives. It also requires companies to hold a water licences for extraction of more than three megalitres per year and has banned the use of evaporation ponds.

Canada

Fracking has been in use in Canada at an industrial level since the 1990s. Concerns about fracking began in late July 2011, when the Government of British Columbia gave Talisman Energy a long-term water licence to draw water from the BC Hydro-owned Williston Lake reservoir, for a twenty year term. Fracking has also received criticism in New Brunswick and Nova Scotia, and the Nova Scotia government is currently reviewing the practice, with recommendations expected in March 2012. The practice has been temporarily suspended, in Quebec, pending an environmental review. The Canadian Centre for Policy Alternatives has also expressed concern.

France

Hydraulic fracturing was banned in France in 2011 after public pressure.

New Zealand

In New Zealand, hydraulic fracturing is part of petroleum exploration and extraction on a small scale mainly in Taranaki and concerns have been raised by environmentalists.

South Africa

There is currently a moratorium on hydraulic fracturing in South Africa's Karoo region despite the interest of several energy companies.

United Kingdom

Hydraulic fracturing is currently proceeding in the United Kingdom operated by Cuadrilla and a number of other companies. In Lancashire, operations were suspended after two small earthquakes subsequent to drilling operations.

Several protest groups have started to oppose hydraulic fracturing in the UK such as nationwide groups like Frack Off and local groups like Ribble Estuary Against Fracking and The Vale Says No

United States

Hydraulic fracturing for the purpose of oil, natural gas, and geothermal production was exempted under the Safe Drinking Water Act. This was a result of the signage of the Energy Policy Act of 2005, also known as the Halliburton Loophole because of former Halliburton CEO Vice President Dick Cheney’s involvement in the passing of this exemption. The result of a 2004 EPA study on coalbed hydraulic fracturing was used to justify the passing of the exemption; however EPA whistleblower Weston Wilson and the Oil and Gas Accountability Project found that critical information was removed from the final report.

Opposers of hydraulic fracturing in the US have focused on this 2005 exemption; however the more primary risk to drinking water is the handling and treatment of wastewater produced by hydraulic fracturing. The EPA and the state authorities do have power “to regulate discharge of produced waters from hydraulic operations” (EPA, 2011) under the Clean Water Act, which is regulated by the National Pollutant Discharge Elimination System (NPDES) permit program "Treatment and Disposal of Wastewater from Shale Gas Extraction | NPDES."www.epa.gov/npdes. Environmental Protection Agency, n.d. Web. 15 Oct. 2011. <http://cfpub.epa.gov/npdes/hydrofracturing.cfm>.. Although this waste is regulated, oil and gas exploration and production (E&P) wastes are exempt from Federal Hazardous Waste Regulations under Subtitle C of the Resource Conservation and Recovery Act (RCRA) despite the fact that wastewater from hydraulic fracturing contains toxins such as total dissolved solids (TDS), metals, and radionuclides. About 750 chemicals have been listed as additives for hydraulic fracturing in a report to the US Congress in 2011.

See also

• Gasland, a 2010 documentary by Josh Fox claim that hydraulic fracturing has many environmental impacts
• Eddy covariance, a method to directly measure emissions of gases displayed by hydraulic fracturing into the atmosphere
• Cost of electricity by source
• Environmental impact of the oil shale industry
• Environmental impact of petroleum
• Environmental concerns with electricity generation

Notes

a. Also spelled "fraccing" or "fracing".

References

1. Charlez, Philippe A. (1997). Rock Mechanics: Petroleum applications, Editions Technip.
2. "frac job", Schlumberger Oilfield Glossary
3. "frac job" Pennsylvania Marcellus Shale GIS Database
4. Post a Job (2011-10-04). "France to Keep Fracking Ban to Protect Environment, Sarkozy Says". Businessweek. Retrieved 2011-11-02.
5. Price, N.J.; Cosgrove, J.W. (1990). Analysis of geological structures. Cambridge University Press. pp. 30–33. ISBN 9780521319584. Retrieved 5 November 2011.
6. Laubach, S.E. (2004). "Coevolution of crack-seal texture and fracture porosity in sedimentary rocks: cathodoluminescence observations of regional fractures". Journal of Structural Geology. 26 (5). Elsevier: 967–982. doi:10.1016/j.jsg.2003.08.019. Retrieved 5 November 2011. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
7. Sibson, R.H. (1975). "Seismic pumping--a hydrothermal fluid transport mechanism". Journal of the Geological Society. 131. London: Geological Society: 653–659. doi:10.1144/gsjgs.131.6.0653. Retrieved 5 November 2011. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
8. Gill, R. (2010). Igneous rocks and processes: a practical guide. John Wiley and Sons. p. 102. ISBN 9781444330656. Retrieved 5 November 2011.
9. "The Barnett Shale" (PDF). North Keller Neighbors Together.
10. Gidley, J.L. et al. (editors), "Recent Advances in Hydraulic Fracturing", SPE Monograph, SPE, Richardson, Texas, 1989.
11. Yew, C.H., "Mechanics of Hydraulic Fracturing", Gulf Publishing Company, Houston, Texas, 1997.
12. Economides, M.J. and K.G. Nolte (editors), "Reservoir Stimulation", John Wiley & Sons, Ltd., New York, 2000.
13. Banks, David (1996). "Permeability and stress in crystalline rocks". Terra Nova. 8 (3): 223–235. doi:10.1111/j.1365-3121.1996.tb00751.x. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
14. Brown, E.T., "Block Caving Geomechanics", JKMRC Monograph 3, JKMRC, Indooroopilly, Queensland, 2003.
15. Frank, U.; Barkley, N. (February 1995). "Remediation of low permeability subsurface formations by fracturing enhancement of soil vapor extraction". Journal of Hazardous Materials. 40 (2): 191–201. doi:10.1016/0304-3894(94)00069-S. ISSN 0304-3894. {{cite journal}}: More than one of |work= and |journal= specified (help)CS1 maint: multiple names: authors list (link)
16. "Geothermal Technologies Program: How an Enhanced Geothermal System Works". .eere.energy.gov. 2011-02-16. Retrieved 2011-11-02.
17. Hydraulic Fracturing Fluids - Composition and Additives (Republished from: Modern Shale Gas Development in the United States by the U.S. Department of Energy). http://geology.com/energy/hydraulic-fracturing-fluids/. 2009.
18. Modern Shale Gas Development in the United States: A Primer.http://www.netl.doe.gov/technologies/oil-gas/publications/epreports/shale_gas_primer_2009.pdf. April 2009. Pg. ES-4.
19. Seale, Rocky (July/August 2007). "Open hole completion systems enables multi-stage fracturing and stimulation along horizontal wellbores" (PDF). Drilling Contractor (Fracturing stimulation ed.). Retrieved October 1, 2009. {{cite journal}}: Check date values in: |date= (help)
20. Quillen, Ed (June 25, 2009). "Fracking, fracing or fraccing?". High Country News.
21. ^ "Chemicals Used in Hydraulic Fracturing" (PDF). Committee on Energy and Commerce U.S. House of Representatives. April 18, 2011.
22. ^ Template:Cite article
23. "Evaluation of Impacts to Underground Sources of Drinking Water by Hydraulic Fracturing of Coalbed Methane Reservoirs; National Study Final Report" (PDF). U.S. EPA. June 2004.
24. ^ Template:Cite article
25. "Pathways To Energy Independence: Hydraulic Fracturing And Other New Technologies". U.S. Senate. May 6, 2011.
26. ^ Template:Cite article
27. "Toxicology and human health effects following exposure to oxygenated or reformulated gasoline" (PDF). US EPA. May 2001. {{cite journal}}: Cite journal requires |journal= (help)
28. "Natural Gas Operations from a Public Health Perspective" (PDF). Internal Journal of Human and Ecological Risk Assessment. September 2010. {{cite journal}}: Cite journal requires |journal= (help)
29. "Ozone mitigation efforts continue in Sublette County, Wyoming". Wyoming's Online News Source. March 2011.
30. Osborn, Stephen G.; Vengosh, Avner; Warner, Nathaniel R.; Jackson, Robert B. (2011-05-09). "Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing". Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1100682108. Retrieved 2011-10-14.
31. "Expanded Site Investigation - Analytical Results Report, Pavillion Area Groundwater Report" (PDF). U.S. EPA Region 8. August 30, 2010.
32. ^ Schmidt, Charles W. "Blind Rush? Shale Gas Boom Proceeds Amid Human Health Questions". Environmental Health Perspectives (119(1)).
33. "Gasland". 2010.
34. "The Future of Natural Gas: An Interdisciplinary MIT Study" (PDF). MIT Energy Initiative. June 2011. {{cite journal}}: Cite journal requires |journal= (help)
35. "Hydraulic Fracturing". U.S. EPA. March 2010.
36. Radiation-fracking link sparks swift reactions By Don Hopey, 5 March 2011 Pittsburgh Post-Gazette
37. "Documents: Natural Gas's Toxic Waste". New York Times. February 26, 2011. {{cite journal}}: Cite journal requires |journal= (help)
38. "Regulation Lax as Gas Wells' Tainted Water Hits Rivers". New York Times. February 26, 2011. {{cite journal}}: Cite journal requires |journal= (help)
39. Shocker: New York Times radioactive water report is false March 8, 2011 ι Abby Wisse Schachter. Report is from a Rupert Murdoch tabloid, The New York Post
40. "E.P.A. Steps Up Scrutiny of Pollution in Pennsylvania Rivers". New York Times. March 7, 2011. {{cite journal}}: Cite journal requires |journal= (help)
41. Griswold, Eliza (17 November 2011). "The Fracturing of Pennsylvania". The New York Times Magazine. Retrieved 21 November 2011.
42. "Water Usage". Chesapeake Energy site hydraulicfracturing.com.
43. "Household Products Database". U.S. Department of Health and Human Services.
44. Chemicals Used in Hydraulic Fracturing. U.S. House of Representatives Committee on Energy and Commerce Minority Staff. April 2011. http://democrats.energycommerce.house.gov/sites/default/files/documents/Hydraulic%20Fracturing%20Report%204.18.11.pdf
45. . {{cite web}}: Check |url= value (help)
46. About Gas: Regulation. http://www.aboutgas.com.au/regulation.html.
47. Colborn, Theo; Kwiatkowski, Carol; Schultz, Kim; Bachran, Mary (2011). "Natural Gas Operations from a Public Health Perspective". Human and Ecological Risk Assessment: An International Journal (17:5): 1039–1056.
48. Fracking tests near Blackpool 'likely cause' of tremors
49. Geomechanical Study of Bowland Shale Seismicity
50. "FAQs - Earthquakes, Faults, Plate Tectonics, Earth Structure: Can we cause earthquakes? Is there any way to prevent earthquakes?" USGS. October 27, 2009.
51. Engelder, Terry (15 September 2011). "Should Fracking Stop? Extracting gas from shale increases the availability of this resource, but the health and environmental effects may be too high. Counterpoint: No, It's Too Valuable". Nature (477): 271–275.
52. Howarth, Robert W.; Ingraffea, Anthony (15 September 2011). "Should Fracking Stop? Extracting gas from shale increases the availability of this resource, but the health and environmental effects may be too high. Point: Yet, it's too high risk". Nature (477): 271–275.
53. Javers, Eamon (8 Nov 2011). "Oil Executive: Military-Style 'Psy Ops' Experience Applied". CNBC.
54. Phillips, Susan (9 Nov 2011). "'We're Dealing with an Insurgency,' says Energy Company Exec of Fracking Foes". National Public Radio.
55. Stewart, Rachel (July 25, 2011). "Editorial A fracking scandal on our back doorstep". Stuff.co.nz. Taranaki Daily News.
56. Reporter: Matthew Carney, Presenter: Kerry O'Brien (February 21, 2011). "The Gas Rush". Four Corners. 0:43 minutes in. ABC. {{cite episode}}: Unknown parameter |city= ignored (|location= suggested) (help)
57. "Northern B.C. fracking licence concerns critics". CBC.ca. July 29, 2011. Retrieved 2011-07-30.
58. "France Vote Outlaws 'Fracking' Shale for Natural Gas, Oil Extraction". Bloomberg.com. July 1, 2011.
59. Maetzig, Rob (July 27, 2011). "Anti-frackers 'need to get real'". Taranaki Daily News. Retrieved 2011-07-27.
60. Maetzig, Rob (August 3, 2011). "Concern as gas drilling intensifies". Taranaki Daily News. Retrieved 2011-08-14.
61. "S.Africa imposes "fracking" moratorium in Karoo". Reuters.com. April 21, 2011.
62. "Shale gas fracking: MPs call for safety inquiry after tremors". BBC. June 8, 2011.
63. Melley, James (2011-09-28). "BBC News - New groups protest at shale gas". Bbc.co.uk. Retrieved 2011-11-02.
64. "Regulation of Hydraulic Fracturing by the Office of Water". US EPA. October 6, 2011. Retrieved October 14, 2011.
65. Sumi, Lisa. "Our Drinking Water at Risk What EPA and the Oil And Gas Industry Don’t Want Us to Know About Hydraulic Fracturing." www.earthworks.org. Oil and Gas Accountability Project & Earthworks, n.d. Web. 16 Oct. 2011.<http://www.earthworksaction.org/pubs/DrinkingWaterAtRisk.pdf>.
66. Regulation of Hydraulic Fracturing Under the Safe Drinking Water Act. http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/wells_hydroreg.cfm. US EPA.October 31, 2011. Retrieved November 7, 2011. OR "Hydraulic Fracturing." www.epa.gov. Environmental Protection Agency, n.d. Web. 5 Oct. 2011. <http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/index.cfm>.
67. Exemption of Oil and Gas Exploration and Production Wastes from Federal Hazardous Waste Regulations." www.epa.gov. Environmental Protection Agency, n.d. Web. 15 Oct. 2011. <http://www.epa.gov/osw/nonhaz/industrial/special/oil/oil-gas.pdf>
68. Natural Gas Drilling in the Marcellus Shale NPDES Program Frequently Asked Question." epa.gov/npdes. Environmental Protection Agency, 16 Mar. 2011. Web. 15 Oct. 2011. <http://www.epa.gov/npdes/pubs/hydrofracturing_faq.pdf>.
69. "Fracking Chemicals Cited in Congressional Report Stay Underground". ProPublica. April 8, 2011. Retrieved July 11, 2011.
70. "Chemicals that may be used in Australian CSG fraccing fluid" Australian Petroleum Ptoduction & Exploration Association Limited
71. Stephen D. Simpson (Jul 12, 2010). "Will The EPA Crack Down On 'Fracking'?". Investopedia.
72. "HydraulicFracturing.com". HydraulicFracturing.com. Retrieved 2011-07-13.

External links

• Hydraulic Fracturing slanted toward environmental issues at Earthworks
• Fracking collected news and commentary at ProPublica
• Shale gas and fracking collected news and commentary at The Guardian
• FracFocus Site indicating chemical composition of fracking fluid of individual wells
• Hydraulic fracturing shale gas extraction at YouTube

• Earth sciences
• Energy
• Environment

• Hydraulic fracturing