Hydraulic Fracturing
Is hydrologic fracturing a suitable form of energy production? Over the past 85 years, the American Petroleum Institute, API, has been developing and refining engineering standards and practices for the industry. The past decade has brought about a new practice which involves hydraulic fracturing in order to produce oil and natural gas in places where conventional technologies are ineffective. This is a rather in depth process. Firstly, a production drill is drilled through the rock layers to intersect the coal seem that contains coal bed methane, CBM. Next, fractures are created or existing fractures are enlarged in the coal seem so that the CBM can be drawn from the well and pumped to the surface. These fractures are created or enlarged by using a thick water-based fluid which is gradually increased by rate and pressure. Then, over time the coal seam is unable to keep up with the fracturing fluid which results in high pressure causing the coal to fracture along the weaknesses within. Sand is pumped into these fractures to keep them ‘propped’ open after the pressures are released. The first diagram in the appendix shows what occurs in the subsurface during a typical hydraulic fracturing event. After a period of fluid recovery or groundwater extraction is when the extraction of CBM occurs. As pumping continues, the pressure eventually decreases so that the methane desorbs from the coal, flows and is extracted through the production well. The fracture created acts as a conduit in the rock or coal formation, allowing the CBM to flow more freely from the coal seems through the fracture system and to the production where gas is pumped to the surface. Unlike conventional gas production, the amount of water extracted declines proportionally with increasing CBM production (US EPA, 2004). The demand of natural gas is expected to increase drastically over the next 20 years, causing the need for innovative production to fill the growing demand. Many may believe that there
References: Green, M. (2012, January 05). Starting the energy debate. Retrieved from http://energytomorrow.org/blog/starting-the-energy-debate/ McLendon, R. (2010, December 10). Big frack attack: Is hydraulic fracturing safe?. Retrieved from http://www.mnn.com/earth-matters/translating-uncle-sam/stories/big-frack-attack-is-hydraulic-fracturing-safe US EPA. (2004, June). Evaluation of impacts to underground sources of drinking water by hydraulic fracturing of coalbed methane reservoirs. Retrieved from http://www.epa.gov/safewater/uic/pdfs/cbmstudy_attach_uic_exec_summ.pdf Appendix