The line of wheat waving in a field in the Alberta countryside is broken abruptly by a dark earthen wall. Packed in behind this berm are more than a dozen tractor-trailer big rigs, including 10 powerful pumper trucks running full bore, generating more than 22,000 horsepower.
As we drive up to the worksite, located near Sundre, about 120 kilometres northwest of Calgary, petroleum engineer Dave Browne from Calgary-based Trican Well Service Ltd. looks at the dust blowing from atop a massive wheeled storage bin or “sand hog,” which holds 110 tonnes of fine-particle sand. “Looks like they’ve started fracking!” Browne says.
At a Trican Well Service fracking site near Sundre, Alta., 45 personnel monitor all aspects of the operation with computers in the control trailer. The project involves hydraulically fracturing two oil wells drilled on the same pad. Each well descends about 2,000 metres deep, then extends horizontally another 1,500 metres into the targeted Cardium sandstone formation. Photo credit: Mark Lowey
Hydraulic fracturing, or fracking, is an innovative technology that has made possible the extraction of oil and natural gas so tightly locked within underground shale rock formations that the resource could not be produced otherwise. Fracking involves pumping a fluid consisting mostly of water and sand, mixed with comparatively small amounts of chemicals (industry prefers the term “additives”) at high pressure down a well to break open the targeted reservoir rock. The sand particles, or proppants, hold open the tiny cracks in the rock, creating a pathway for oil and gas to flow into the wellbore and be pumped to the surface.
Much of the public concern about fracking is focused on the chemicals used and their potential impacts on human health and the environment, including drinking-water wells. Between 2005 and 2009, the 14 leading oil and gas service companies (including Canadian firms) used more than 2,500 hydraulic fracturing products containing 750 chemicals and other components, according to a report by the United States House of Representatives’ Committee on Energy and Commerce. Companies used fracking products containing 29 chemicals that are known or possible human carcinogens; regulated under the US Safe Drinking Water Act for their risks to human health or listed as hazardous air pollutants under the US Clean Air Act. Some chemicals used, such as benzene (a contaminant in diesel fuel) and lead, are extremely toxic. Others, like methanol and formaldehyde, are deemed hazardous. However, chemicals used in hydraulic fracturing in the US, except for diesel fuel, are exempt from federal environmental laws, despite worries from scientists. “Some of the chemicals used in fracturing fluids have proven harmful effects on humans and wildlife,” says Sara Souther, a conservation biologist and post-doctoral researcher at the University of Wisconsin. Moreover, Souther says, the impact on the environment of a mixture of these chemicals is poorly understood.
Fracking in Canada is not exempt from environmental laws and regulations. Nevertheless, the rapid expansion of shale gas development over the past decade “has occurred without a corresponding investment in monitoring and research addressing the impacts on the environment, public health and communities,” stated the Council of Canadian Academies expert panel’s recent report this year on the environmental impacts of shale gas extraction that was commissioned by Environment Canada.
Along with chemical additives pumped down the well, the fluid that is returned, called flowback, often contains minerals naturally present in the rock formation, which can include heavy metals and, in some black shales, naturally occurring radioactive materials. “Given all the other minerals and chemicals that are in the various rock masses, and given all the chemicals added to the frack fluid, what are the possible combinations of chemical reactions that can occur and the impacts?” asks Anthony Ingraffea, professor of civil and environmental engineering at Cornell University in New York. The general consensus in the science community is that no one knows because little research has been done. That hasn’t stopped sharp words from being levelled at the fracking industry. Frank Smith, retired professor of chemistry at Memorial University of Newfoundland, says as a chemist he is “outraged” that any company anywhere would still be using or has used dangerous chemicals. Fracking companies should be required to use ingredients that are not harmful to human health or the environment, Smith says.
Unlike many US states, fracking companies in Canada are required to disclose the chemicals and other additives used in their formulations. Alberta, for example, requires disclosure of all hazardous and non-hazardous ingredients to the Alberta Energy Regulator. If there’s an incident, the regulator can publicly disclose a company’s complete list, says Ernie Perkins, principal scientist at Alberta Innovates Technology Futures. Oil and gas companies in Alberta and British Columbia also publicly disclose their frack fluids on the FracFocus Chemical Disclosure Registry website, although “trade secret” ingredients are exempt.
Hydrogeologist John Cherry, who chaired the Council of Canadian Academies’ report, says that simply disclosing the chemicals isn’t sufficient. Government should require companies to publicly provide detailed information on the potential health and environmental impacts of all fracking chemicals, says Cherry, director of the University Consortium for Field-Focused Groundwater Contamination Research, associate director of G360 Centre for Applied Groundwater Research and adjunct professor of engineering at the University of Guelph.
Trican Well Service petroleum engineer Dave Browne checks the chemicals trailer, which transports all chemicals to the job in locked metal totes to prevent shifting and leakage. Photo credit: Mark Lowey
At Trican Well Service’s fracking operation, no hazardous chemicals or additives are being used to induce cracks in the Cardium Formation deep below ground to ease the flow of oil, says Browne. The job involves fracking two wells each about 2,000 metres deep (far below any potable water), with each running horizontally about 1,500 metres through the rock formation.
To frack several zones along the horizontal wells, the company is pumping from the surface at pressures of 5,000 to 6,500 pounds per square inch (35,000 to 45,000 kilopascals). The job will use a total of 5.24 million litres of freshwater from a nearby river, 925 tonnes of sand similar to beach sand, about 100,000 cubic metres of nitrogen gas and five different additives. (The total amount of chemicals used was 27,420 litres, of which 16,950 litres were non-toxic, biodegradable and non-bioaccumulating, says Browne.) The nitrogen reduces the amount of water needed and helps carry the frack fluid out of the well. “We’re challenging ourselves and all our suppliers to change what we’re using for additives to make them all non-hazardous. Industry as a whole is moving in this direction,” says Browne. The additives are:
- A non-hazardous chemical stabilizer to stop clay particles in the rock formation from swelling and plugging up the well;
- A “green” friction reducer, a polymer that reduces friction of the water against the well pipe (called “slickwater” fracking), allowing more efficient pumping;
- A biocide (naturally biodegradable within 24 hours) to kill bacteria in the formation that can cause sludge, corrosion or toxic hydrogen sulphide gas;
- A “green breaker,” a non-hazardous chemical that breaks the long molecular chains of the friction-reducing polymer after pumping stops, so the frack fluid flows back out of the well;
- A surfactant which helps the sand particles disperse evenly into the fractures. (Household dishwasher soap is a surfactant.)
Much of the criticism directed at fracking stems from fears that the chemicals used will contaminate drinking water. The oil and gas industry claims there is not one case of contaminated drinking water in the scientific literature. However, the Council of Canadian Academies (CCA) disputes that, saying that the lack of evidence doesn’t equate to proof. “There’s never been a fracking site that’s had anything close to rigorous groundwater monitoring,” Cherry says.
A lack of monitoring appears ubiquitous across the industry, say scientists. In the US, a 2014 study by the University of Wisconsin’s Souther and researchers at eight other institutions identified 12 ways that shale gas production could potentially impact ecosystems. They found that of the 24 states with active shale reservoirs, only five states maintain public records of spills and accidents. In 2013 in Pennsylvania, companies failed to report more than one-third of the documented 116 spills, which were instead discovered in routine well inspections. “If we want to understand the impacts of chemical contamination due to shale gas development, we need accurate data across all jurisdictions on spills, contamination and chemicals in fracturing fluids,” Souther says.
At Trican’s fracking job, every aspect of the operation — from the mixing of water, sand and additives at the surface, the temperatures and pressures in the target formation, to another company’s nearby well — is monitored by computers in the onsite control trailer. Unlike in some US states that allow fracking flowback fluid to be held in uncovered pits, regulations in Western Canada require flowback to go into sealed tanks and then be trucked for disposal to approved deep-injection wells. All chemical additives are transported to the job site in containers locked in steel totes to prevent shifting and leakage. “It’s all 100 percent contained,” Browne says.
A more likely route of chemical contamination is through poorly cemented or sealed wellbores. The chemical most often involved is methane gas, which can occur naturally in geological formations or can leak from nearby drilling operations. In peer-reviewed research published this year, Avner Vengosh, professor of geochemistry and water quality at Duke University, as well as scientists from four other universities, examined the potential for “stray gas” contamination in drinking-water wells near homes in Pennsylvania and Texas shale formations. “There is very strong evidence for stray gas contamination because of leaking of the shale gas well,” Vengosh says. “It is actually leaking because of poor cement, of poor installation of the shale gas well” — not the fracking operation itself. But because no studies have been done, “we don’t know what the health impacts are of elevated levels of methane in drinking water,” he adds.
In a peer-reviewed study for the National Academy of Science, Ingraffea and others looked at more than 41,000 oil and gas wells drilled in Pennsylvania over a 13-year period, along with well-inspection reports. They found that about four percent of newly drilled wells leak methane almost immediately. The percentage of leaky wells increases over time. “The industry knows very, very well that they’ve had this problem forever,” Ingraffea says.
Engineering geologist Maurice Dusseault and two colleagues at the University of Waterloo reported this year that thousands of wellbores are leaking methane, including 27,000 leakage reports in Alberta since 1971, about 10 percent of all active and suspended gas wells in British Columbia, and about 20 percent of all energy wells in Saskatchewan. Cement integrity is not routinely tested after fracking operations. However, “we know of no incidents of fracturing fluids rising up the wellbore in which you’re actually doing fracturing,” Dusseault says.
Dusseault proposed a “Canadian roadmap for improving long-term wellbore integrity” to fix the leaky wells problem. However, industry and science seem to be at loggerheads. The Alberta Energy Regulator, Dusseault says, told him not to interfere in its business and his work was attacked on an industry blog. “Here’s somebody trying to identify the problem, trying to come up with a roadmap to address the issues and make the public understand that the problems are manageable, well understood and small,” he says. “Instead, the oil industry slams the door.”
All the scientists interviewed agreed that a multi-level groundwater monitoring system — which would cost a fraction of large, multi-well drilling pads — is needed wherever shale gas development occurs. “It’s the essential first step if you want to assess whether the groundwater got contaminated and, if so, how long does it take until contamination disappears,” says Bernhard Mayer, professor of isotope geochemistry at the University of Calgary. Cherry adds that “the federal government can’t sit on the sidelines” when it comes to supporting much-needed, unbiased research on shale gas development and its impacts.
“They should coordinate and partially fund a big-league national research program.”
Ingraffea adds a sobering thought: “If we don’t know what the long-term cumulative impacts might be on the environment and human health, then really we are conducting a large-scale experiment on the environment and human health.”
While many scientists advocate a go-slow approach to allow for more research and groundwater monitoring, some scientists like Ernie Perkins at Alberta Innovates Technology Futures insist that hydraulic fracturing, when done correctly, is as safe as any other industrial operation. Fracking “is an industrial process in a peculiar environment and there always is potential for human error or problems,” Perkins says. “It’s up to us to make sure we have sufficient monitoring, rules and regulations so those are minimized and we can handle them appropriately.”