Fracking

Hydraulic fracturing (fracking) and acidising (acid fracking) are two of the most common methods for well stimulation. The flow chart shows that hydraulic fracking and acid fracking, highlighted in yellow, are two categories of unconventional hydraulic methods. But acidising is complicated by the fact that matrix acidising is considered conventional. Note that it takes place below the fracture gradient of the rock. In the UK legislative and hydrocarbon permitting context (see Fracking in the United Kingdom), Adriana Zalucka et al. have reviewed the various definitions, as well as the role of key regulators and authorities, in a peer-reviewed article published in 2021. They have proposed a new robust definition for unconventional well treatments: {{Blockquote The above definition focuses on increasing permeability, rather than on any particular extraction process. It is quantitative, using the generally agreed 0.1 md cut-off value, below which rocks are considered impermeable. It exempts borehole cleaning processes like acid squeeze or acid wash from being classed as unconventional, by using the 1 m radius criterion. It avoids a definition based on, for example, the quantity of water injected, which is controversial, or the injection pressure applied (whether the treatment is above or below the fracture gradient, as shown in the flow chart above). It also exempts non-hydrocarbon wells from being classed as unconventional. The definition takes into account the views of the hydrocarbon industry and the US Geological Survey, in particular. A low permeability (by consensus defined as less than 0.1 millidarcies) implies that the resource is unconventional, meaning that it requires special methods to extract the resource. Above that value, conventional methods suffice. Unconventional resources are also characterised by being widely distributed, with low energy density (i.e. in a low concentration) and ill-defined in volume. There are no discrete boundaries, in contrast to those bounding a conventional hydrocarbon reservoir. Although the definition above was developed within the UK context, it is universally applicable. ==Hydraulic fracking==

Hydraulic fracking is the most commonly used well stimulation technique. It involves the fracturing of formations in bedrock by a pressurized liquid. The process involves the high-pressure injection of "fracking fluid" (primarily water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants (either sand or aluminium oxide) hold the fractures open. and the first commercially successful application followed in 1949. As of 2012, 2.5 million "frac jobs" had been performed worldwide on oil and gas wells, over one million of those within the U.S. Drilling and hydraulic fracking have made the United States a major crude oil exporter as of 2019, but leakage of methane, a potent greenhouse gas, has dramatically increased. Increased oil and gas production from the decade-long fracking boom has led to lower prices for consumers, with near-record lows of the share of household income going to energy expenditures. Fracking is highly controversial. Its proponents highlight the economic benefits of more extensively accessible hydrocarbons (such as petroleum and natural gas), the benefits of replacing coal with natural gas, which burns more cleanly and emits less carbon dioxide (CO2), and the benefits of energy independence. Opponents of fracking argue that these are outweighed by the environmental impacts, which include groundwater and surface water contamination, noise and air pollution, the triggering of earthquakes, and the resulting hazards to public health and the environment. including confirmation of chemical, physical, and psychosocial hazards such as pregnancy and birth outcomes, migraine headaches, chronic rhinosinusitis, severe fatigue, asthma exacerbations and psychological stress. Adherence to regulation and safety procedures are required to avoid further negative impacts. The scale of methane leakage associated with hydraulic fracking is uncertain, and there is some evidence that leakage may cancel out any greenhouse gas emissions benefit of natural gas relative to other fossil fuels. Increases in seismic activity following hydraulic fracking along dormant or previously unknown faults are sometimes caused by the deep-injection disposal of fracking flowback fluid (a byproduct of hydraulically fracked wells), For these reasons, hydraulic fracturing is under international scrutiny, restricted in some countries, and banned altogether in others. The European Union is drafting regulations that would permit the controlled application of hydraulic fracturing. ==Geology==

Mechanics Fracturing rocks at great depth frequently become suppressed by pressure due to the weight of the overlying rock strata and the cementation of the formation. This suppression process is particularly significant in "tensile" (Mode 1) fractures which require the walls of the fracture to move against this pressure. Fracturing occurs when effective stress is overcome by the pressure of fluids within the rock. The minimum principal stress becomes tensile and exceeds the tensile strength of the material. Fractures formed in this way are generally oriented in a plane perpendicular to the minimum principal stress, and for this reason, hydraulic fractures in wellbores can be used to determine the orientation of stresses. In natural examples, such as dikes or vein-filled fractures, the orientations can be used to infer past states of stress. Veins Most mineral vein systems are a result of repeated natural fracturing during periods of relatively high pore fluid pressure. The effect of high pore fluid pressure on the formation process of mineral vein systems is particularly evident in "crack-seal" veins, where the vein material is part of a series of discrete fracturing events, and extra vein material is deposited on each occasion. One example of long-term repeated natural fracturing is in the effects of seismic activity. Stress levels rise and fall episodically, and earthquakes can cause large volumes of connate water to be expelled from fluid-filled fractures. This process is referred to as "seismic pumping". Dikes Minor intrusions in the upper part of the crust, such as dikes, propagate in the form of fluid-filled cracks. In such cases, the fluid is magma. In sedimentary rocks with a significant water content, fluid at fracture tip will be steam. == History ==

Precursors , North Dakota, United States Fracking as a method to stimulate shallow, hard rock oil wells dates back to the 1860s, though the general concept of using water pressure to destroy rock was known as early as ancient Rome, in the form of ruina montium. Dynamite or nitroglycerin detonations were used to increase oil and natural gas production from petroleum bearing formations. On 24 April 1865, US Civil War veteran Col. Edward A. L. Roberts received a patent for an "exploding torpedo". Oil and gas wells The relationship between well performance and treatment pressures was studied by Floyd Farris of Stanolind Oil and Gas Corporation. This study was the basis of the first hydraulic fracturing experiment, conducted in 1947 at the Hugoton gas field in Grant County of southwestern Kansas by Stanolind. In the Soviet Union, the first hydraulic proppant fracturing was carried out in 1952. Other countries in Europe and Northern Africa subsequently employed hydraulic fracturing techniques including Norway, Poland, Czechoslovakia (before 1989), Yugoslavia (before 1991), Hungary, Austria, France, Italy, Bulgaria, Romania, Turkey, Tunisia, and Algeria. American geologists gradually became aware that there were huge volumes of gas-saturated sandstones with permeability too low (generally less than 0.1 millidarcy) to recover the gas economically. the Piceance Basin, and the Green River Basin, and in other hard rock formations of the western US. Other tight sandstone wells in the US made economically viable by massive hydraulic fracturing were in the Clinton-Medina Sandstone (Ohio, Pennsylvania, and New York), and Cotton Valley Sandstone (Texas and Louisiana). sedimentary beds are usually nearly horizontal, so horizontal wells have much larger contact areas with the target formation. Shales Hydraulic fracturing of shales goes back at least to 1965, when some operators in the Big Sandy gas field of eastern Kentucky and southern West Virginia started hydraulically fracturing the Ohio Shale and Cleveland Shale, using relatively small fracs. The frac jobs generally increased production, especially from lower-yielding wells. In 1976, the United States government started the Eastern Gas Shales Project, which included numerous public-private hydraulic fracturing demonstration projects. During the same period, the Gas Research Institute, a gas industry research consortium, received approval for research and funding from the Federal Energy Regulatory Commission. This new completion technique made gas extraction widely economical in the Barnett Shale, and was later applied to other shales, including the Eagle Ford and Bakken Shale. The first horizontal well in the Barnett Shale was drilled in 1991, but was not widely done in the Barnett until it was demonstrated that gas could be economically extracted from vertical wells in the Barnett. As of 2013, massive hydraulic fracturing is being applied on a commercial scale to shales in the United States, Canada, and China. Several additional countries are planning to use hydraulic fracturing. == Process ==

According to the United States Environmental Protection Agency (EPA), hydraulic fracturing is a process to stimulate a natural gas, oil, or geothermal well to maximize extraction. The EPA defines the broader process to include acquisition of source water, well construction, well stimulation, and waste disposal. Water-soluble gelling agents (such as guar gum) increase viscosity and efficiently deliver proppant into the formation. When propane is used it is turned into vapor by the high pressure and high temperature. The propane vapor and natural gas both return to the surface and can be collected, making it easier to reuse and/or resale. None of the chemicals used will return to the surface. Only the propane used will return from what was used in the process. The proppant is a granular material that prevents the created fractures from closing after the fracturing treatment. Types of proppant include silica sand, resin-coated sand, bauxite, and man-made ceramics. The choice of proppant depends on the type of permeability or grain strength needed. In some formations, where the pressure is great enough to crush grains of natural silica sand, higher-strength proppants such as bauxite or ceramics may be used. The most commonly used proppant is silica sand, though proppants of uniform size and shape, such as a ceramic proppant, are believed to be more effective. The fracturing fluid varies depending on fracturing type desired, and the conditions of specific wells being fractured, and water characteristics. The fluid can be gel, foam, or slickwater-based. Fluid choices are tradeoffs: more viscous fluids, such as gels, are better at keeping proppant in suspension; while less-viscous and lower-friction fluids, such as slickwater, allow fluid to be pumped at higher rates, to create fractures farther out from the wellbore. Important material properties of the fluid include viscosity, pH, various rheological factors, and others. Water is mixed with sand and chemicals to create hydraulic fracturing fluid. Approximately 40,000 gallons of chemicals are used per fracturing. A typical fracture treatment uses between 3 and 12 additive chemicals. • Guar gum and other water-soluble gelling agents—increases viscosity of the fracturing fluid to deliver proppant into the formation more efficiently. Tensile stresses are generated ahead of the fracture's tip, generating large amounts of shear stress. The increases in pore water pressure and in formation stress combine and affect weaknesses near the hydraulic fracture, like natural fractures, joints, and bedding planes. Different methods have different location errors and advantages. Accuracy of microseismic event mapping is dependent on the signal-to-noise ratio and the distribution of sensors. Accuracy of events located by seismic inversion is improved by sensors placed in multiple azimuths from the monitored borehole. In a downhole array location, accuracy of events is improved by being close to the monitored borehole (high signal-to-noise ratio). Monitoring of microseismic events induced by reservoir stimulation has become a key aspect in evaluation of hydraulic fractures, and their optimization. The main goal of hydraulic fracture monitoring is to completely characterize the induced fracture structure, and distribution of conductivity within a formation. Geomechanical analysis, such as understanding a formations material properties, in-situ conditions, and geometries, helps monitoring by providing a better definition of the environment in which the fracture network propagates. The next task is to know the location of proppant within the fracture and the distribution of fracture conductivity. This can be monitored using multiple types of techniques to finally develop a reservoir model that accurately predicts well performance. Horizontal completions Since the early 2000s, advances in drilling and completion technology have made horizontal wellbores much more economical. Horizontal wellbores allow far greater exposure to a formation than conventional vertical wellbores. This is particularly useful in shale formations which do not have sufficient permeability to produce economically with a vertical well. Such wells, when drilled onshore, are now usually hydraulically fractured in a number of stages, especially in North America. The type of wellbore completion is used to determine how many times a formation is fractured, and at what locations along the horizontal section. In North America, shale reservoirs such as the Bakken, Barnett, Montney, Haynesville, Marcellus, and most recently the Eagle Ford, Niobrara and Utica shales are drilled horizontally through the producing intervals, completed and fractured. 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 steel casing, cemented or uncemented, set in the drilled hole. Once the drilling rig has been removed, a wireline truck is used to perforate near the bottom of the well, and then fracturing fluid is pumped. Then the wireline truck sets a plug in the well to temporarily seal off that section so the next section of the wellbore can be treated. Another stage is pumped, and the process is repeated along the horizontal length 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 due to be fractured, the bottom sliding sleeve is opened using one of several activation techniques and the first stage gets pumped. Once finished, the next sleeve is opened, concurrently isolating the previous 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 that had far fewer feet of producing zone exposed. == Uses ==

Hydraulic fracturing is used to increase the rate at which substances such as petroleum or natural gas can be recovered 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 extraction of natural gas and oil from rock formations deep below the earth's surface (generally ), which is greatly below typical groundwater reservoir levels. At such depth, there may be insufficient permeability or reservoir pressure to allow natural gas and oil to flow from the rock into the wellbore at high economic return. Thus, creating conductive fractures in the rock is instrumental in extraction from naturally impermeable shale reservoirs. Permeability is measured in the microdarcy to nanodarcy range. Since the late 1970s, hydraulic fracturing has been used, in some cases, to increase the yield of drinking water from wells in a number of countries, including the United States, Australia, and South Africa. ==Economic effects==

Hydraulic fracturing has been seen as one of the key methods of extracting unconventional oil and unconventional gas resources. According to the International Energy Agency, the remaining technically recoverable resources of shale gas are estimated to amount to , tight gas to , and coalbed methane to . As a rule, formations of these resources have lower permeability than conventional gas formations. Therefore, depending on the geological characteristics of the formation, specific technologies such as hydraulic fracturing are required. Although there are also other methods to extract these resources, such as conventional drilling or horizontal drilling, hydraulic fracturing is one of the key methods making their extraction economically viable. The multi-stage fracturing technique has facilitated the development of shale gas and light tight oil production in the United States and is believed to do so in the other countries with unconventional hydrocarbon resources. Other studies have suggested that the economic benefits are outweighed by the externalities and that the levelized cost of electricity (LCOE) from less carbon- and water-intensive sources is lower. The primary benefit of hydraulic fracturing is to offset imports of natural gas and oil, where the cost paid to producers otherwise exits the domestic economy. However, shale oil and gas is highly subsidised in the US, and has not yet covered production costs – meaning that the cost of hydraulic fracturing is paid for in income taxes, and in many cases is up to double the cost paid at the pump. Research suggests that hydraulic fracturing wells have an adverse effect on agricultural productivity in the vicinity of the wells. One paper found "that productivity of an irrigated crop decreases by 5.7% when a well is drilled during the agriculturally active months within 11–20 km radius of a producing township. This effect becomes smaller and weaker as the distance between township and wells increases." ==Public debate==

(Spain, 2012) (2018) Politics and public policy Popular movement and civil society organizations An anti-fracking movement has emerged both internationally with involvement of international environmental organizations and nations such as France and locally in affected areas such as Balcombe in Sussex where the Balcombe drilling protest was in progress during mid-2013. The considerable opposition against hydraulic fracturing activities in local townships in the United States has led companies to adopt a variety of public relations measures to reassure the public, including the employment of former military personnel with training in psychological warfare operations. According to Matt Pitzarella, the communications director at Range Resources, employees trained in the Middle East have been valuable to Range Resources in Pennsylvania, when dealing with emotionally charged township meetings and advising townships on zoning and local ordinances dealing with hydraulic fracturing. The US Export-Import Bank, an agency of the US government, provided $4.7 billion in financing for fracking operations set up since 2010 in Queensland, Australia. Alleged Russian state advocacy In 2014 a number of European officials suggested that several major European protests against hydraulic fracturing (with mixed success in Lithuania and Ukraine) may be partially sponsored by Gazprom, Russia's state-controlled gas company. The New York Times suggested that Russia saw its natural gas exports to Europe as a key element of its geopolitical influence, and that this market would diminish if hydraulic fracturing is adopted in Eastern Europe, as it opens up significant shale gas reserves in the region. Russian officials have on numerous occasions made public statements to the effect that hydraulic fracturing "poses a huge environmental problem". Current fracking operations Hydraulic fracturing is currently taking place in the United States in Arkansas, California, Colorado, Louisiana, North Dakota, Oklahoma, Pennsylvania, Texas, Virginia, West Virginia, and Wyoming. As of 2024, there are currently seven major fracking operations active in the United States. These are the Bakken operation in North Dakota and Montane, Niobrara operation in Wyoming and Colorado, Anandarko in Northern Texas and Oklahoma, Permian and Eagle Ford in Texas, Haynesville in Texas and Louisiana, and the large Appalachia site. Although a hydraulic fracturing moratorium was recently lifted in the United Kingdom, the government is proceeding cautiously because of concerns about earthquakes and the environmental effect of drilling. Hydraulic fracturing is currently banned in France and Bulgaria. became a center of opposition to hydraulic fracturing of shale. The movie presented problems with groundwater contamination near well sites in Pennsylvania, Wyoming and Colorado. documentary called FrackNation as a response to the statements made by Fox in Gasland, claiming it "tells the truth about fracking for natural gas". FrackNation premiered on Mark Cuban's AXS TV. The premiere corresponded with the release of Promised Land. In April 2013, Josh Fox released Gasland 2, his "international odyssey uncovering a trail of secrets, lies and contamination related to hydraulic fracking". It challenges the gas industry's portrayal of natural gas as a clean and safe alternative to oil as a myth, and that hydraulically fractured wells inevitably leak over time, contaminating water and air, hurting families, and endangering the Earth's climate with the potent greenhouse gas methane. In 2014, Scott Cannon of Video Innovations released the documentary The Ethics of Fracking. The film covers the politics, spiritual, scientific, medical and professional points of view on hydraulic fracturing. It also digs into the way the gas industry portrays hydraulic fracturing in their advertising. In 2015, the Canadian documentary film Fractured Land had its world premiere at the Hot Docs Canadian International Documentary Festival. Research issues Typically the funding source of the research studies is a focal point of controversy. Concerns have been raised about research funded by foundations and corporations, or by environmental groups, which can at times lead to at least the appearance of unreliable studies. ==Health risks==

There is concern over the possible adverse public health implications of hydraulic fracturing activity. A 2011 hazard assessment recommended full disclosure of chemicals used for hydraulic fracturing and drilling as many have immediate health effects, and many may have long-term health effects. In June 2014 Public Health England published a review of the potential public health impacts of exposures to chemical and radioactive pollutants as a result of shale gas extraction in the UK, based on the examination of literature and data from countries where hydraulic fracturing already occurs. The executive summary of the report stated: "An assessment of the currently available evidence indicates that the potential risks to public health from exposure to the emissions associated with shale gas extraction will be low if the operations are properly run and regulated. Most evidence suggests that contamination of groundwater, if it occurs, is most likely to be caused by leakage through the vertical borehole. Contamination of groundwater from the underground hydraulic fracturing process itself (i.e. the fracturing of the shale) is unlikely. However, surface spills of hydraulic fracturing fluids or wastewater may affect groundwater, and emissions to air also have the potential to impact on health. Where potential risks have been identified in the literature, the reported problems are typically a result of operational failure and a poor regulatory environment." A 2012 report prepared for the European Union Directorate-General for the Environment identified potential risks to humans from air pollution and ground water contamination posed by hydraulic fracturing. A 2012 guidance for pediatric nurses in the US said that hydraulic fracturing had a potential negative impact on public health and that pediatric nurses should be prepared to gather information on such topics so as to advocate for improved community health. A 2017 study in The American Economic Review found that "additional well pads drilled within 1 kilometer of a community water system intake increases shale gas-related contaminants in drinking water." A 2022 study conduced by Harvard T.H. Chan School of Public Health and published in Nature Energy found that elderly people living near or downwind of unconventional oil and gas development (UOGD) -- which involves extraction methods including fracking—are at greater risk of experiencing early death compared with elderly persons who don't live near such operations. Statistics collected by the U.S. Department of Labor and analyzed by the U.S. Centers for Disease Control and Prevention show a correlation between drilling activity and the number of occupational injuries related to drilling and motor vehicle accidents, explosions, falls, and fires. Extraction workers are also at risk for developing pulmonary diseases, including lung cancer and silicosis (the latter because of exposure to silica dust generated from rock drilling and the handling of sand). The U.S. National Institute for Occupational Safety and Health (NIOSH) identified exposure to airborne silica as a health hazard to workers conducting some hydraulic fracturing operations. NIOSH and OSHA issued a joint hazard alert on this topic in June 2012. Another report done by the Canadian Medical Journal reported that after researching they identified 55 factors that may cause cancer, including 20 that have been shown to increase the risk of leukemia and lymphoma. The Yale Public Health analysis warns that millions of people living within a mile of fracking wells may have been exposed to these chemicals. Despite these health concerns and efforts to institute a moratorium on fracking until its environmental and health effects are better understood, the United States continues to rely heavily on fossil fuel energy. In 2017, 37% of annual U.S. energy consumption is derived from petroleum, 29% from natural gas, 14% from coal, and 9% from nuclear sources, with only 11% supplied by renewable energy, such as wind and solar power. == Environmental justice ==

Fracking can cause many different environmental justice issues. One of the main justice issues associated with fracking is the effect the wells have on the communities they are placed in. The locations of the wells result in the poor, people of color, and native peoples being disproportionately affected by the negative externalities of fracking operations. This becomes an issue because many of these fracking sites are built in poor, rural communities, where people need employment. There have been many cases where there has been an observed decline in employment following fracking implementation. Since the Appalachian fracking boom in 2008, thirty large gas companies in Ohio, Pennsylvania, and West Virginia have logged a large economic output, but jobs in the area fell by 1% while nationally job opportunities rose 14%, employment grew 4% in the fracking regions while the nation employment rate grew by 10%, and income had grown three quarters the rate of the national average. According to Sean O'Leary, a senior researcher at Ohio River Valley Institute, makes the point that "While some studies have found that economic conditions improve in areas where fracking is introduced, these studies fail to negate the fact that the negative externalities from fracking are centralized in these regions (poor rural regions) and that they often burden those who do not receive economic benefits from fracking." Native peoples also face a disproportionate amount of fracking in their communities, as companies and the government often take their land and destroy it for mineral resources such as gas and oil. According to the Classic Journal, legislation has been created in the United States to allow this to occur, specifically federal acts such as the Mineral Leasing Act of 1938 and the Indian Self- Determination and Education Assistance Act of 1975 that both restrict Natives' rights to resources on their lands. ==Environmental impacts==

in Alice Springs, Australia The potential environmental effects of hydraulic fracturing include air pollution and contribution climate change, high water consumption, groundwater contamination, land use, induced earthquakes, noise pollution, and various health effects on humans. Air contamination Air emissions are primarily methane that escapes from wells, along with industrial emissions from equipment used in the extraction process. A few of the main reasons why drinking water can be contaminated according to the EPA are: • Water removal to be used for fracking in times or areas of low water availability Hydraulic fracturing uses between of water per well, with large projects using up to . Additional water is used when wells are refractured.) or by produced water (the returning fluids, which also contain dissolved constituents such as minerals and brine waters). The possibility of groundwater contamination from brine and fracturing fluid leakage through old abandoned wells is low. Produced water is managed by underground injection, municipal and commercial wastewater treatment and discharge, self-contained systems at well sites or fields, and recycling to fracture future wells. Fracking causes many different types of pollution, including water pollution. After the well is fracked and produces oil and gas, fracking fluids often remain underground, where it may contaminate groundwater and connect to aquifer systems. The wastewater produced from the operations is also toxic and must be stored correctly, treated, and then discharged, but it is often stored in holding ponds that can leak into the surrounding ground and impact wildlife. Per- and polyfluoroalkyl substances also known as "PFAS" or "forever chemicals" have been linked to cancer and birth defects. The chemicals used in fracking stay in the environment. Once there those chemicals will eventually break down into PFAS. These chemicals can escape from drilling sites and into the groundwater. PFAS are able to leak into underground wells that store million gallons of wastewater. In addition to water contamination, fracking uses a substantial amount of water. One well can use anywhere from 1.5 million to 16 million gallons of water. There is concern about the impact of fracking on local water resources, especially in the drier regions of the United States. These fracking sites are consuming millions of gallons of water from aquifers that are already dwindling. According to the New York Times, "Nationwide, fracking has used up nearly 1.5 trillion gallons of water since 2011. That's how much tap water the entire state of Texas uses in a year." Land use In the United States over are being used for fossil fuels. This is equivalent of six Yellowstone National Parks. About of land is needed per each drill pad for surface installations. Well pad and supporting structure construction significantly fragments landscapes which likely has negative effects on wildlife. These sites need to be remediated after wells are exhausted. Each well pad (in average 10 wells per pad) needs during preparatory and hydraulic fracturing process about 800 to 2,500 days of noisy activity, which affect both residents and local wildlife. In addition, noise is created by continuous truck traffic (sand, etc.) needed in hydraulic fracturing. Induced seismic activity Hydraulic fracturing has been tied to induced seismicity or earthquakes in regions where few or no earthquakes were previously recorded. Fracking has been the major catalyst for at least 2% of earthquakes in the United States according to the United States Geological Survey, but could be higher. The connection was first recognized when a well was drilled outside a plant in Denver, and more than 700 small to modest size earthquakes ensued, corresponding with the volume and pressure of the injections into the well. Texas and Oklahoma have been two of the regions impacted most by fracking induced seismic activity. Prior to 2008, not a single earthquake had been recorded in the Dallas- Fort Worth region of Texas, but since then the region has been experiencing a sixfold increase in earthquakes. The rise in earthquakes in the area directly coincides with the increase in oil drilling activity. == Regulations ==

Countries using or considering use of hydraulic fracturing have implemented different regulations, including developing federal and regional legislation, and local zoning limitations. The ban was upheld by an October 2013 ruling of the Constitutional Council. Some other countries such as Scotland have placed a temporary moratorium on the practice due to public health concerns and strong public opposition. Germany has announced draft regulations that would allow using hydraulic fracturing for the exploitation of shale gas deposits with the exception of wetland areas. Many states in Australia have either permanently or temporarily banned fracturing for hydrocarbons. In 2019, hydraulic fracturing was banned in UK. The European Union has adopted a recommendation for minimum principles for using high-volume hydraulic fracturing. In 2012, Vermont became the first state in the United States to ban hydraulic fracturing. On 17 December 2014, New York became the second state to issue a complete ban on any hydraulic fracturing due to potential risks to human health and the environment. == See also ==

Explanatory notes References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 ==Sources==