The Environmental Effects of Oil and Natural Gas Extraction Through Hydraulic Fracturing

Hydraulic fracturing, also known and henceforth referred to as fracking, is a technique that has been used in oil and natural gas extraction for more than six decades now. A fluid, which often contains water, sand, and other chemical agents, is injected into a well and pumped in high-pressure so that cracks are formed within the deep rock formations where the oil and natural gas is to be extracted (Uddameri et al. 15). This mining technique has come under scrutiny and criticism in the last five years due to concerns that it might have potentially dangerous effects on the environment. This paper seeks to investigate various aspects of fracking, and their impact on the environment to debunk any wrong perceptions or myths.

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Natural gas and oil are usually trapped within underlying rocks, and often, there are no outlets through the strata for the oil and gas to escape and thus be extracted. The purpose of fracking is to provide these outlets and, therefore, hasten the process and speed through which the minerals are removed (Uddameri et al. 39). Overlying rock strata weight is often a significant hindrance towards oil and natural gas extraction. Reservoirs are usually impermeable to fluid and gasses due to the pressure exerted by this weight. For fracturing to occur, the fluid pressure of the fluid injected must overcome the effective stress of the rocks. High volume Hydraulic fracturing, also referred to as massive fracking is an up-scaled form of fracking whereby high amounts of proppant are injected into the crust (Drogos 28). It has its beginnings in America, whereby geologists invented it in an attempt to increase the permeability of gas saturated sandstones, to facilitate economically viable extraction of the natural gas. Until 1980, wells drilled were often vertical. Horizontal Oils became commonplace as they proved to be far more effective than vertical ones in oil and gas extraction.

Fractures are often localized, and often do not extend very far from the well. The distance is usually determined by the pressure of the liquid, as well as the rate of frictional loss (Schug & Hildenbrand 74). The injected fluid contains a proppant, which is, a suspension comprising materials such as sand, ceramic or other material. This proppant is usually lodged in the fractures to maintain their width, which reduces the pressure of the injected fluid decreases and after the pressurized pumping is stopped. The strength of the proppant and the force of the fluid increase as depth increases because with increased depth comes a rise in the force exerted by the overlying rocks (Kaden & Tracie 32).

Fracturing fluid leak-off is common in most of the drilling and fracturing processes. It is the permeation of the fluid into surrounding rock strata. It may sometimes decrease the efficiency with which the oil or natural gas is extracted due to a change in the fracture geometry or damage to the formation matrix (Speight 17). The casing along the length of the wellbore is perforated to determine at what point a fracture should be created. This way, the number of fissures or outlets of the pressurized fluid is controlled. Fracturing fluids composition usually differ, but they are typically composed of 90% water, 9.5% and 0.5% chemical additives (Kaden & Tracie 14). Other materials that have been used in fracturing fluids include liquefied petroleum gas, nitrogen, carbon dioxide, air, among others. The composition of proppants is determined by the necessary grain strength or the permeability of the target rock. The viscosity of the proppant is also considered, as less viscous fluid, e.g., slickwater, is more useful if the depth is high (Uddameri et al. 48).

Fracking has been associated with various phenomena and has since raised controversy due to reports that it may affect the seismic potential of the areas in which it is conducted. The pressure generated from the injection of the pressurized liquid is highly controlled and has so far been thought to be localized only at the target locations (Drogos 58). However, the permeability of the rocks may allow the fluid to seep through it, thereby spreading the pressure to surrounding areas and faults. It would theoretically increase the incidence or magnitude of tremors and quakes in the surrounding areas. Areas around such a wellbore, if affected by the pressure, could remain seismically volatile up to a few months after the drilling has stopped (Uddameri et al. 114). Various earthquakes have been associated with fracking that has occurred in nearby areas, such as the 2011 earthquake in Prague, Oklahoma.

The relationship between the fracking site and process and the nearby fault lines is a significant determinant of whether the fracking-induced seismic activity is likely to occur. Due care must be exercised where fracking is to be conducted in areas that are close to natural tectonic faults. The fault lines state of stress also indicates the probability of seismic activity (Holloway & Oliver 67). Measurement of seismicity should be conducted before, during and after fracking to measure the risk of a tremor or quake. Measurements before the earthquake in the proposed site and surrounding areas help obtain a seismic baseline against which activity during and after fracking is compared. It also assists in the identification of the existing faults and their location (Speight 40). Microseismic monitoring is also done at such a site and in close to show any motion taking place in the crust.

The association between fracking and earth tremors and quakes is however weakly evidenced, and the link remains weak (Schug & Hildenbrand 61). It should also be noted that oil extraction causes not all human-induced seismic activity through fracking. The highest incidence of human-induced earthquakes in the US occur in Oklahoma, and while these may be associated with fracking for oil and natural gas extraction, a more likely causative agent would be the water injected into the ground through wastewater wells (Drogos 26). Most of this wastewater is water that is obtained from the backflow of fractured oil and hydrocarbon extraction sites. The incidence of earthquakes per year in Oklahoma has also increased steadily since 2009, which has contributed to the correlation between the earthquakes and wastewater disposal in wells.

In as much as the fracking technology is under intense criticism, it has its advantages to the environment, the major one being the increasing efficiency in oil and natural gas extraction. Fracking assists in the development of fractures in the natural gas saturated bedrock are therefore facilitating the permeability of the gas at a speed that is economical (Speight 64). As a result, oil products are now cheaper compared to coal and are therefore better and more preferable source of energy. Fracking as a contributor to pollution also has much less effect on the environment than coal mining and usage.

Fracking has however been noted to result in the escape of hydrocarbon gasses into the environment. These gasses are not only poisonous but they are also highly flammable could cause disastrous accidents (Holloway & Oliver 31). Natural gas, when leaked into the atmosphere, also increases the concentration of carbon-based gaseous compounds, which in turn results in global warming. The adverse effects to the environments are extensive. Global warming causes melting the glacial cover of the Polar Regions, leading to increased water levels in the oceans and reservoirs, potentially disrupting earth ecosystems (Schug & Hildenbrand 55).

Perhaps one of the most significant controversies in fracking is the contamination of underground water, thereby posing the danger of chemical poisoning to human beings and other organisms. The fracking process is conducted to create cracks in the bedrock to allow for the gasses to permeate through to reservoirs for extraction. However, the pressure generated may also result in similar fractures that lead to underground water reservoirs which hold drinking water (Drogos 46). If these gasses and chemicals are released into the water, the water becomes toxic and is no longer fit for drinking. It should be noted that less than 5% of all water on the earth's surface is drinkable, and this fit to drink water comes from underground reservoirs.

It calls for the refining of drilling procedures and technologies to ensure that underground aquifers are preserved. So far, regulations have been put in place by most environmental and mining regulators towards this end (Holloway & Oliver 87). Also notable is that these aquifers occur in shallow parts of the crust, compared to the depths from which the oil and natural gas are extracted. Unless due care is not taken, this factor makes it relatively easy to prevent the poisoning of such aquifers.

Conclusively, fracking is a mining method that has greatly facilitated the extraction of oil and natural gas from the soaked bedrock (Uddameri et al. 82). It has increased the economic sustainability of mining sites by allowing the gas and oil to permeate at higher rates than they would if the method was not used. Some of the concerns raised regarding fracking are about its effect on the environment. While fracking has been associated with seismic activity, the link between the two is not strong enough, and extensive evidence backed research needs to be carried out to ascertain the relationship and prove the correlation. The pollutant effect to the environment caused by leaks of natural gas can also be reduced and eliminated with increased regulation and the practice of due care (Kaden & Tracie 126).

Works Cited

Drogos, Donna L. Hydraulic Fracturing: Environmental Issues, 2015.

Holloway, Michael D, and Oliver Rudd. Fracking: The Operations and Environmental Consequences of Hydraulic Fracturing. New York, NY: John Wiley & Sons, 2013.

Kaden, Debra, and Tracie L. Rose. Environmental and Health Issues in Unconventional Oil and Gas Development. 2016.

Schug, Kevin, and Zacariah L. Hildenbrand. Advances in Chemical Pollution, Environmental Management and Protection: Volume 1. Cambridge, MA: Academic Press, 2017.

Speight, James G. Handbook of Hydrualic Fracturing. 2016.

Uddameri, Venkatesh, Audra Morse, and Kay J. Tindle. Hydraulic Fracturing Impacts and Technologies: A Multidisciplinary Perspective. 2016.