Shale Gas and Hydraulic Fracking
Shale gas refers to natural gas that is contained in shale rock, mudstone or laminated siltstones. Unlike conventional natural gas deposits, where gas is extracted easily from permeable reserves through standard drilling practices, shale gas is an unconventional resource. Production requires special drilling techniques and stimulation to economically extract the natural gas from the rock. Canadian provinces with identified shale gas potential include British Columbia, Alberta, Saskatchewan, Ontario, Quebec, New Brunswick and Nova Scotia.
Almost all of southwestern Ontario and some small portions of southeastern Ontario have bedrock units similar to gas producing shale rocks located in Quebec and areas of the United States, however, no comprehensive assessment of shale gas potential has been completed in Ontario. As a result, in 2009, the Ontario Geological Survey of the Ministry of Northern Development, Mines and Forestry initiated a three-year geoscience study, including a collection of surface and buried rock samples, to assess the potential for shale gas extraction. Figure 6.1.1 shows the areas (or “plays”) in Ontario with shale gas potential. Notably, the bulk of this potential is located beneath private lands and not Crown lands; therefore, the primary planning document relevant to shale gas extraction is the Provincial Policy Statement, 2005.
Figure 6.1.1. Distribution of black shale with shale gas potential in Ontario. Note: Black shale is the term used to identify dark-coloured
shale rock that is a potential source for natural gas. Black shale rocks typically contain 1 per cent or more of organic carbon. Source:
Ministry of Natural Resources.
Extraction is typically performed using horizontal drilling to allow access to a large surface area, followed by hydraulic fracturing to extract the natural gas. Hydraulic fracturing, also referred to as “fracking,” is accomplished by injecting large amounts of high-pressure fluid, propping agents and chemicals into the drilled wells. The high pressure used for fracking is designed to exceed the rock strength and crack the rock, while the propping agents (such as sand or other granular particles) hold the fractured rocks open and allow the previously trapped natural gas to enter the drilled well and be drawn to the surface for recovery. An aqueous slurry, containing chemical additives that vary depending on the rock formation and its depth, is used to optimize the stimulation process. A single well can require millions of litres of high-pressure water for proper hydraulic fracturing, and wells may require repeated fracturing. A schematic of this process is provided in Figure 6.1.2.
Figure 6.1.2. Shale gas fracturing (“fracking”), depicting both vertical and horizontal drilling. Source: U.S. Environmental Protection Agency.
Ontario has a long history of oil and gas production. In 1858, North America’s first commercial crude oil well was established in Oil Springs, Lambton County. In 1889, the first commercial natural gas well in Ontario was drilled in the Essex County area. Since then, it is estimated that upwards of 50,000 oil and gas wells have been drilled; however, the Ministry of Natural Resources (MNR) has records for only 27,000 wells. In 2010, Ontario had a total of 92 commercial oil and gas producers operating 1,223 active oil wells, 1,214 active natural gas wells and 29 wells producing both oil and natural gas.
While it remains unproven whether Ontario has economically viable reserves of shale gas, one exploration well for natural gas in a shale formation has been drilled in Chatham. Due to insufficient natural gas volumes, the well was plugged without having completed the hydraulic fracture treatment. At least one oil and gas company has leased land in southwestern Ontario with the intention of producing shale gas.
Increased natural gas production would have some benefits for Ontario. Ontario’s natural gas demand accounts for roughly 30 per cent of all Canadian gas consumption and western Canada supplies most of this demand. The use of natural gas in Ontario’s power sector is expected to climb to nearly one-third of total provincial natural gas demand by 2020. This could have an impact on existing natural gas infrastructure, including pipelines and storage facilities. An increase in local production may help alleviate the potential strain on the existing supply.
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Environmental Concerns
Although other jurisdictions have been extracting shale gas for several years, a number of environmental concerns have been raised.
For fracking, operators can choose to use either fresh water, deep formation waters (brine), or recycled fluids. Other hydraulic injection fluids, such carbon dioxide, nitrogen or a mixture of propane and butane are being examined as possible mediums. When water is used as the fracking fluid, either off-site surface water resources, nearby groundwater aquifers (accessed through drilled wells), or formation water (brine) can be used to supply the water for the project.
When water is used as the fracking agent, the amount of water needed depends on a variety of factors including porosity of the shale and its depth. An estimated 11 million litres of water demand is required for each fracturing procedure performed on a single well in areas of the U.S. and Canada. To continue producing economic quantities of shale gas, a well may need to be fractured multiple times during its lifespan to increase the rate of recovery. The large water withdrawals required for each fracking procedure could disrupt aquatic ecosystems, downstream wetlands and aquifer supplies.
As noted in previous ECO annual reports, some groundwater aquifers are tapped to their limit and many southern Ontario communities are experiencing increasing demands on existing natural resources. If a groundwater aquifer is to be used, an analysis of its other uses, such as nearby public and private water supply wells, is needed in order to determine if they would be negatively affected. This is especially important since the fresh water taken for fracking is considered “consumptive,” in that it is not returned directly to the source. Water quality and quantity are inherently related. If the water quantity in the aquifer decreases as a result of the withdrawals for fracking, the water quality can be negatively affected because the concentration of pollutants or other contaminating materials in the water increases.
Water Contamination and Chemical Exposure Issues
As noted above, the liquid used for hydraulic fracturing consists of water, propping agents and chemicals. After fracking, a large amount of this liquid solution returns to the surface. Depending on a variety of factors, the composition of the liquid that resurfaces can change, as some of the chemicals are consumed during the process. The liquid that resurfaces can even contain naturally occurring radioactive materials, such as radium, thorium and uranium. This liquid requires proper handling by the developers, including wastewater treatment, reuse or waste disposal, to avoid impacts to the environment and human health.
Water contamination from the liquid that resurfaces can occur if there are improper or inadequate handling facilities at the surface (e.g., ineffective stormwater controls, faulty casing construction, operational errors or pit leakages). Human error can result in chemical spills on-site, releasing contaminants into the environment and causing a serious health hazard for those in the immediate vicinity. In some cases, potential contamination can pose a threat to drinking water sources – most groundwater sources used for drinking water are within 100 metres of the surface and Ontario’s shale formations occur both at shallow depths (0-200 metres) and deeper depths (over 1,000 metres).
Although the chemicals used in fracking vary based on geographical region, general classifications of chemicals include: acids; bactericides; corrosion inhibitors; friction reducers; gelling agents; iron controllers; scale inhibitors; and surfactants. Of these, high levels of total dissolved solids, chlorides, surfactants, gelling agents and metals present in the water that resurfaces have been identified as posing the greatest environmental concern. Notably, dissolved iron and salt can occur naturally in the formation water.
The U.S. Environmental Protection Agency (U.S. EPA) is currently conducting a scientific study to investigate the possible impacts of fracking on drinking water. The agency notes there are serious concerns with fracking and its potential impact on “drinking water, human health and the environment, which demands further study.” Initial results of this study are expected in late 2012.
Air Pollution
Large pits can be used to store the hydraulic fracturing fluid as it resurfaces from the ground, before it is transported for reuse, storage or treatment. The liquid can contain a variety of contaminants, such as volatile organic compounds or methanol, which can have an impact on local air quality. Methanol is a toxic substance that is considered a cumulative poison with chronic exposure. Methanol is relatively volatile, evaporating quickly upon exposure to air and forming high vapour concentrations. Methanol was the most widely used chemical for fracking in the U.S. between 2005 and 2009.
Areas with shale gas production have experienced an increase in truck traffic, from transporting equipment to removing waste. Some wells have reportedly required an average of 1,500 truck trips for water delivery to the site. Each trip contributes to increased local air emissions, and imposes additional wear and tear on local roadways.
The U.S. EPA has identified the use of diesel engines for compressors, generators, drill rigs and pumps as a potential source of emissions. Wells can take as long as five weeks of continuous drilling, which requires constant use of heavy equipment and machinery. Given the proximity of the shale gas potential in Ontario to densely populated areas, the equipment, traffic and noise pollution may pose a concern to local residents and ecosystems.
Pathways and Migration
During the fracking process, the new pathways created can form connections with pre-existing formations in the rock. If there are pre-existing vertical cracks, it could allow the fracking liquid and natural gas to migrate upward toward the surface.
Methane contamination of drinking water from shale gas development has been documented in areas of the U.S., which has also experienced an increase in the number of cases of human exposure to methane. High levels of methane, the main component of natural gas, can cause asphyxiation and create an explosive hazard in confined spaces. Methane is also highly flammable. Possible exposure pathways include direct leaks from poorly constructed wells or underground “communication” between different geological channels. Methane is also a potent greenhouse gas that has a global warming potential that is 72 times that of carbon dioxide over a 20-year time horizon.
Ontario has several hazardous waste disposal facilities located in southwestern Ontario, along with several historic deep well industrial waste disposal sites. The risks that shale gas developments pose to these wells may need to be assessed.
The Ontario Government and Shale Gas
In 2010, the government made amendments to the Oil, Gas and Salt Resources Act (OGSRA ) that allow MNR to respond to technological advances, including shale gas extraction. These amendments did not introduce any new environmental protection measures relating to shale gas extraction, but a number of the existing environmental protection measures are likely to apply to this process. Under the existing framework, most of the required approvals are classified instruments and would, therefore, be posted on the Environmental Registry.
For example, the Ontario Water Resources Act (OWRA) requires individuals taking more than 50,000 litres of water per day to obtain a Permit to Take Water (PTTW) from the Ministry of the Environment (MOE). Permit holders record data on the daily quantity of water taken and report this information annually to MOE. The OWRA also regulates any discharges of wastewater as sewage works. Also, the Environmental Protection Act’s approvals process would apply to any emissions to air or production of solid wastes from shale gas operations. While the existing regulatory framework, such as it is, would apply to shale gas extraction, it may not be adequate to fully protect the natural environment from all of the unique environmental issues of shale gas extraction.
ECO Comment
The OGSRA provides MNR with authority over licences or permits relating to the establishment, operation and plugging of a well. This authority could be applied to address environmental concerns related to these aspects of shale gas exploration and development. Therefore, a co-ordinated approach between MNR and MOE would be a minimum requirement to ensure all environmental aspects are properly examined if hydraulic fracturing operations are to commence in Ontario. Areas that have seen a great amount of commercial interest, such as New York and Quebec, are conducting extensive environmental assessments before production is allowed to proceed. If economically viable reserves of shale gas are confirmed in Ontario, MOE and MNR must ensure that the regulatory framework is sufficient to protect the natural environment and water resources from potential environmental effects.
Given that MNR does not have records for an estimated 23,000 historic oil and gas wells, interaction with preexisting man-made wells is a serious concern. Evaluation of fracturing in shale rock depends on good knowledge of the density of the rock, as well as any pre-existing faults in the area. Therefore, it is critical to have information on the location of faults, nearby wells and underground waste disposal facilities in the area, as well as general rock characteristics.
While the prospect of a new and plentiful domestic energy resource is appealing, the ECO notes that associated environmental damage could outweigh the energy benefits of increased natural gas supply. Any future development of Ontario’s shale gas resources must be undertaken with the public assurance that the cumulative effects of such development do not have unintended consequences. Given the close proximity of Ontario’s shale formations to groundwater supplies, such development must be cognizant of the reality that, once groundwater is contaminated, remediation may be prohibitively expensive.
| Recommendation 10:
The ECO recommends that MNR and MOE review and publicly report on the sufficiency of the regulatory framework to protect water resources and the natural environment from shale gas extraction. |
For ministry comments, please see Appendix C.
| Previous section: Part 6 – Emerging Issues |
| Next section: The Roots of Sustainability: Engaging the Soil Carbon Solution |
| This is an article from the 2010/11 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2011. "Shale Gas and Hydraulic Fracking." Engaging Solutions, ECO Annual Report, 2010/11. Toronto: The Queen's Printer for Ontario. 103-108.
