Water Online

December 2014

Water Online the Magazine gives Water & Wastewater Engineers and end-users a venue to find project solutions and source valuable product information. We aim to educate the engineering and operations community on important issues and trends.

Issue link: http://wateronline.epubxp.com/i/426767

Contents of this Issue

Navigation

Page 10 of 24

White Paper wateronline.com ■ Water Online The Magazine 8 I n an attempt to proffer a solution to the global high demand for energy, energy production has been increased with the introduction of hydraulic fracturing for accessing low-permeability, organic- rich shale formations and tight gas sands, with the resultant increase in natural gas production. These benefits of hydraulic fracturing have led to exemption of flow-back fluids from regulatory bodies in the U.S. and mandates within the Resource Conservation and Recovery Act (RCRA) and the Safe Drinking Water Act (SDWA). Hydraulic fracturing, a non-conventional method of drilling, is believed to have negative effects on source water. This article addresses the purported impacts of hydraulic fracturing processes on source water, the mechanism of the contamination of source water, the possible solutions to these negative impacts of hydraulic fracturing, and the need for further investigation and scientific research on the behavior of hydraulic fracturing fluids with the aim of identifying potential risks to source water. Hydraulic fracturing functions as a double-edged sword: It permits the extraction of oil and natural gas in an unconventional reservoir with low permeability but also carries significant environmental risk. To summarize the practice, hydraulic fracturing is a well- stimulation technique used for the extraction of oil and natural gas in unconventional reservoirs with low permeability, such as shale, coal beds, and tight sands 1 . To understand the environmental risks associated with hydraulic fracturing, also known as fracking, a brief overview of the fracking water cycle is below. Hydraulic Fracturing Water Cycle The hydraulic water cycle is divided into five stages 2 , as shown in Figure 1. 1. Water acquisition 2. Chemical mixing 3. Well injection 4. Flow-back and produced water 5. Wastewater treatment and waste disposal The large volume of water needed for fracking is transported to the site, followed by the mixing of the water with chemicals and sand (proppant) at the well site. The well injection process as shown in Figure 2 involves the injection of engineered fluids or chemicals and granular materials into the well at high pressure between 15 to 100 psi (pound force per square inch) to shatter petroleum reserves and stimulate the flow of oil or natural gas to the surface 1 . After the fracturing of the well, the injection fluids are forced out under pressure. The flow-back fluids are either re-injected to Class II injection wells, recycled at the site, or transported to wastewater treatment facilities 2 . Regardless of the high resource potential and economic benefits of the process, there is growing concern about the negative potential environmental impacts and human health implications, which may include groundwater and surface water contamination, land destruction, air pollution, geologic disruption, greenhouse emissions, and radiation 1,3 . The risk of hydraulic fracturing is more focused on its impact on source water and the potential contamination route, which would be the area of focus in this report. Although it is believed that hydraulic fracturing poses a risk to water resources, the extent of the risk and/ or damage already inflicted are yet to be properly The Big Fracking Question: Is Drinking Water At Risk? Understanding the impacts of hydraulic fracturing ("fracking") on source water, in both quantity and quality, is of vital importance to industry, the economy, and society. The latest research on the subject is presented, along with possible solutions to help overcome known and potential problems. By Blaise Ekechukwu and Jafar Soltan Hydraulic fracturing functions as a double-edged sword: it permits the extraction of oil and natural gas in an unconventional reservoir with low permeability, but also carries significant environmental risk.

Articles in this issue

Links on this page

Archives of this issue

view archives of Water Online - December 2014