By Cliff Montgomery – July 23, 2013
The Congressional Research Service recently released a very informative, short study on such unconventional gas and oil production methods as hydraulic fracturing and directional drilling.
The report provides a detailed, non-partisan review of the many environmental concerns of these extraction methods – which includes the controversial process known as ‘fracking’.
Below, The American Spark offers quotes from the study – we have printed the report’s entire section on environmental concerns.
“The United States has seen a resurgence in petroleum production, mainly driven by technology improvements—hydraulic fracturing and directional drilling—developed for natural gas production from shale formations. Application of both of these technologies enabled natural gas to be economically produced from shale and other unconventional formations, and contributed to the United States becoming the world’s largest natural gas producer in 2009.
“Use of these technologies has also contributed to the rise in U.S. oil production over the last few years. […]
“The rapid expansion of oil and gas extraction using hydraulic fracturing—both in rural and more densely populated areas—has raised concerns about its potential environmental and health impacts. These concerns have focused primarily on potential impacts to groundwater and surface water quality, public and private water supplies, and air quality. […]”
Environmental Concerns and Responses
“As with other energy sources or fuel production, the development of unconventional oil and gas resources can pose environmental risks, many of which potentially may be mitigated with appropriate safeguards and existing technology.
“The recent large-scale increase in unconventional oil and gas production may result in both negative and positive environmental impacts, comparatively speaking. For example, increased unconventional oil and gas production activity has in some cases placed a strain on water resources, and on wastewater treatment plants that were not designed to remove chemicals, salts, and other contaminants from hydraulic fracturing flowback and produced water.
“On the other hand, natural gas is seen by many as a ‘bridge’ fuel that provides more energy per unit of greenhouse gas produced than some alternatives (e.g., coal), and has only recently been produced in sufficient quantity and at low enough prices to provide a viable alternative fuel that is widely regarded as relatively cleaner-burning.
“Nonetheless, the rapid expansion of oil and natural gas extraction using high-volume hydraulic fracturing—both in rural and more densely populated areas—has generated controversy due to its potential scale and impacts on land and water resources, air quality, communities, and landowners.
“Water quality issues have received the most attention, and of these, the potential risks associated with well stimulation by hydraulic fracturing have been at the forefront. Complaints of contaminated well water have emerged in various areas where unconventional oil and gas development is occurring, although regulators have not reported a direct connection between hydraulic fracturing of shale formations and groundwater contamination.
“In shale formations, the vertical distance separating the target zone from usable aquifers generally is much greater than the length of the fractures induced during hydraulic fracturing. Thousands of feet of rock layers typically overlay the produced portion of shale, and these layers serve as barriers to flow. In these circumstances, geologists and state regulators generally view as remote the possibility of creating a fracture that could reach a potable aquifer.
“[But] If the shallow portions of shale formations were developed, then the thickness of the overlying rocks would be less and the distance from the shale to potable aquifers would be shorter, posing more of a risk to groundwater.
“In contrast to shale, coal-bed methane (CBM) basins often qualify as underground sources of drinking water. Injection of fracturing fluids directly into or adjacent to such formations would be more likely to present a risk of contamination, and this is where initial regulatory attention and study was focused.
“State regulators have expressed more concern about the groundwater contamination risks associated with developing a natural gas or oil well (drilling through an overlying aquifer and casing, cementing, and completing the well), as opposed to hydraulic fracturing per se. The challenges of sealing off the groundwater and isolating it from possible contamination are common to the development of any oil or gas well, and are not unique to hydraulic fracturing.
“Identifying the source or cause of groundwater contamination can be difficult for various reasons, including the complexity of hydro-geologic processes and investigations, a lack of baseline testing of nearby water wells prior to drilling and fracturing, and the confidential business information status traditionally provided for fracturing compounds.
“In cases that have been investigated, regulators generally have determined that groundwater contamination was caused by failure of well-bore casing and cementing, well operation problems, or surface activities, rather than the hydraulic fracturing process.
“The debate over the groundwater contamination risks associated with hydraulic fracturing operations has been fueled in part by the lack of scientific studies to assess more thoroughly the current practices and related complaints and uncertainties. To address this issue, Congress has directed the Environmental Protection Agency (EPA) to conduct a study on the relationship between hydraulic fracturing and drinking water.
“The ‘hydraulic fracturing’ debate also has been complicated by terminology. Many who express concern over the potential environmental impacts associated with hydraulic fracturing do not differentiate the well stimulation process of ‘fracing’ or ‘fracking’ from the full range of activities associated with unconventional oil and gas exploration and production.
“The management of the large volumes of wastewater produced during natural gas production (including flowback from hydraulic fracturing operations and water produced from source formations) has emerged as a significant water quality issue. In some areas, such as portions of the Marcellus Shale region, capacity is limited for wastewater disposal using underground injection wells (historically, the most common produced- water disposal practice in oil and natural gas fields), and surface discharge of wastewater is an increasingly restricted option.
“Additionally, the injection of large volumes of wastewater into disposal wells has been associated with some instances of induced seismicity.
“Other water quality concerns—associated with both conventional and unconventional oil and natural gas extraction—include the risks of contaminating ground and surface water from surface spills, migration of methane gas and contaminants into residential water wells from faulty well construction, and siltation of streams from drilling and pad construction activities.
“Because of the large volumes of water needed to extract shale gas and tight oil, water consumption issues have emerged as well. Water use issues include the impacts that large water withdrawals might have on groundwater resources, streams and aquatic life, and other competing uses (e.g., municipal or agricultural uses).
“Air pollution associated with unconventional oil and natural gas production has also raised public health concerns and has drawn regulatory scrutiny. Air pollutants can be released during various stages of oil and natural gas production, not just hydraulic fracturing. Emission sources include pad, road, and pipeline construction, well drilling and completion, and flowback activities, and natural gas processing, storage, and transmission equipment.
“Key pollutants include methane (the main component of natural gas and a potent greenhouse gas), Volatile Organic Compounds (VOCs), nitrogen oxides, sulfur dioxide, particulate matter, and various hazardous air pollutants.
“According to EPA, the oil and gas industry is a significant source of VOCs, which react with nitrogen oxides to form ozone (smog). EPA has identified hydraulically fractured gas wells during flowback as an additional source of VOC emissions in the natural gas industry.
“In addition to hydraulically fractured gas wells, releases of methane and other pollutants can occur where natural gas is produced in association with oil, [even if…] natural gas gathering pipelines and other infrastructure are lacking.
“In such cases, the natural gas generally must be flared or vented. Flaring reduces VOC emissions compared to venting, but like venting, it contributes to greenhouse gas emissions without producing an economic value or displacing other fuel consumption.”
