Fracking furor: increased exploration of shale gas structures using hydraulic fracturing, or fracking, has sparked protests from Canadians who fear the process will contaminate groundwater.
In a province where massive oil deposits were first discovered in 1947, routine exploration activity rarely attracts much public interest, let alone protest. But in order to extract the oil believed to be hundreds of metres below Blood lands, Murphy Oil may have to resort to a controversial technique known as hydraulic fracturing. Fracking, as it is commonly called, involves injecting liquids laced with various chemicals into a reservoir to break the host rock, which allows the hydrocarbons to flow to a well. "It's disturbing to think what this place will look like five years from now when the oil company is gone," says Rebeka Many Grey Horses, who participated in the September blockade. "The chief and council failed to consult the people on this. We had no other way of drawing attention to our concerns."
The protestors' concerns are similar to those expressed by residents of other parts of Canada and the United States where oil and gas companies intend to use hydraulic fracturing to tap into petroleum reserves. One of the big fears among members of the public is that fracking will allow fluids to migrate upward and contaminate groundwater. Others have raised alarms about the huge volumes of chemically contaminated water used in such operations. Some of that water usually flows back to the well and ultimately to the surface and must be disposed of safely.
Earlier this year, a group of demonstrators spent a month walking 600 kilometres from Rimouski, Que. on the lower St. Lawrence River to Montreal where they joined several thousand others who staged a major protest against a natural gas exploration project that involves fracking. "We want to send a message that this government needs to put this whole industry on hold for at least 20 years until we know what's happening to these 450-million-year-old formations that we're destroying in order to extract gas," says organizer Philippe Duhamel.
A similar demonstration occurred outside the provincial legislature in Fredericton, N.B. on a holiday Monday in August and attracted more than 1,000 people. The New Brunswick government has introduced stiff regulations requiring oil and gas companies to disclose the chemicals used in fracking and to post security bonds to protect homeowners from any environmental mishaps. Quebec, meanwhile, has gone further and imposed a moratorium on hydraulic fracturing until further studies of the process are completed.
Officials with energy companies, as well as representatives of industry associations, insist that public fears of contaminated water supplies are misplaced, and even some prominent environmentalists agree. "There's no evidence that fracturing fluids have migrated upward to the level of groundwater," says Matt Horne, acting director of the climate change program with the Pembina Institute, an environmental think tank based in Drayton Valley, Alta.
Still, Home and others have reservations about fracking. "The scale and scope of the activity have changed dramatically in the past 10 years," he says. "We need to step back and study it and make sure we have adequate regulations in place."
But industry representatives insist their track record suggests otherwise. They contend that hydraulic fracturing has been a common practice for 60 years in Alberta and the petroleum producing western states south of the border. That's due to variations in the geology of petroleum deposits. In most cases, conventional oil and gas resides in porous and highly permeable sandstone and limestone formations and can easily be pumped to the surface. Sometimes, though, the hydrocarbons are found in so-called tight formations and can only be flushed out by injecting liquids under intense pressure.
Kerry Guy, manager of natural gas advocacy with the Calgary-based Canadian Association of Petroleum Producers (CAPP), says that Alberta's Energy Resources Conservation Board has detailed files on 167,000 wells that have been subjected to fracking since the early 1950s. "They are on record as saying that they are not aware of a single case of fracturing fluids migrating upwards into drinking water supplies," says Guy.
In the past decade or so, energy companies have begun developing unconventional sources of oil and gas for several reasons. First, conventional reserves are in decline. Second, rising prices and technological advances have made it feasible to tackle deeper, previously uneconomic formations. These factors have led to a rush to explore shale gas structures in Quebec, New Brunswick and especially northeastern British Columbia. Such deposits are generally located 2,000 to 3,000 metres below the surface, several hundred metres below conventional deposits and two kilometres or more below groundwater, which is generally found at depths of 80 to 150 metres.
The development of shale gas reserves represents a new horizon for Canada's energy producers, and one the country badly needs, says Guy, despite the lingering public doubts about the safety of hydraulic fracturing. "Conventional natural gas has been in decline in North America," he says. "The industry has been living hand to mouth for 20 years and that has made prices quite volatile. A lot of new reserves are now economically accessible. As a result, we have a 100-year supply at current demand in North America."
The challenge, however, is that shale is impermeable. Natural gas will not flow unassisted from this rock to a well and then to the surface. Fortunately, it is also very brittle and susceptible to fracturing. As well, energy companies are now able to penetrate much further into these formations due to the advent of horizontal drilling. That is, they drill straight down to the natural gas-laden shale and then bore several hundred metres into it horizontally.
Only then does a fracking operation begin. Mike Dawson, president of the Calgary-based Canadian Society for Unconventional Gas, explains that a hydraulic fracture takes place in four stages. First, liquids--in most cases water--are pumped into the well at extraordinarily high pressure to crack the shale. Next, the drill crew pumps additional fluids to create a sort of spider web of fractures that can be 500 to 800 metres in length. The first burst of liquid is similar to a stone hitting a windshield and causing a chip. The second, says Dawson, "is like taking a sledgehammer to a windshield."
The crew then injects liquids containing minute grains of round, heat and pressure-resistant sand known as proppants. Finally, the pressure is reduced, allowing the fluids to flow back to the well bore. But the proppants remain in place. They keep open the fractures, which serve as pathways that allow the gas to migrate through the shale.
Dawson notes that the liquid and proppants constitute 99.5 per cent by volume of the material injected into a well. The balance consists of chemicals that serve a variety of purposes. Gellants are used to enhance the viscosity of the fracking fluid, improve the suspension of the proppants and reduce friction. One of the most common is guar gum, a white powder derived from the guar bean, which is grown commercially in India and Pakistan. More refined versions of this bean are used as thickening agents in dairy products, sauces and other foodstuffs.
In some cases, tiny quantities of metals such as boron, zirconium, titaniura and iron are used as crosslinkers, which act on the gellants that keep the proppants suspended and allow them to be carried further into a reservoir. Biocides, some of them manufactured and some derived from natural sources, are used to prevent the growth of bacteria that can produce hydrogen sulphide, which can turn natural gas from 'sweet' to 'sour.' Soap-like surfactants are used to enhance the ability of the fracture fluid to flow back to the surface, and occasionally C[O.sub.2] or [N.sub.2] are injected into the well to improve this recovery.
The biggest issue for many environmentalists and community activists is the volume of water required for fracking. For example, the B.C. government issued licenses in 2009 allowing oil and gas companies to use 86.5 billion litres for hydraulic fracturing, although they consumed only about five per cent of that. In April 2010, however, Houston-based Apache Corp. mounted North America's largest ever fracking operation in the Horn River basin of northeastern B.C. The company conducted 247 fracks from a 16-well pad and pumped 980 million litres of liquid.
The water used in fracking is sometimes purchased from municipalities and sometimes drawn directly from rivers or lakes. Dawson says that in most cases some of the liquids are recovered, though that can vary from less than 50 per cent to as much as 90 to 95 per cent, depending on the character of the formation. Fracking fluids can be re-used, though not in every case. "If it's not reusable, you have to pump it into a disposal well in close vicinity to where you're drilling," Dawson adds. "you're not allowed to dispose of it on the surface in any way."
The problem with consumption on such a large scale, says Pembina's Home, is that at least two agencies, the B.C. Oil and Gas Commission and the provincial environment ministry, regulate the use of water and sometimes one branch doesn't know what the other is doing. "B.C. has a fragmented approach to water regulation," Home says. "There's no clear picture of how much water is being used in the shale gas region and what that might mean in 10 or 15 years if the development reaches some of the industry forecasts."
But at least one B.C. municipality has turned that kind of demand to its advantage. Dawson Creek, a community of some 12,000 people located 400 kilometres northeast of Prince George and just inside the Alberta-B.C. border, is the major service centre for oil companies developing the Montney Basin shale gas deposits. Kevin Henderson, Dawson Creek's director of infrastructure and sustainable development, says the town has been selling almost 25 per cent of the output from its water treatment plant for fracking operations. Henderson acknowledges that any increased demand would put a strain on the system and could force the municipality to balance the needs of local taxpayers as well as rural residents who draw on the town's water supply.
However, Shell Oil has agreed to invest $10 million in a wastewater treatment plant that will draw effluent from the community's five sewage lagoons, clean it up and use it as a fracking liquid. That will reduce demand on the town's water treatment plant and it will mean that effluent will no longer be discharged into the Kiskatinaw River, the source of Dawson Creek's drinking water. Henderson says the municipality is kicking in $1.5 million, but could not afford to pay the full price.
Hydraulic fracturing is likely to remain controversial, despite the record in Alberta and other traditional petroleum producing regions. Oil and gas companies are being forced by the depletion of conventional reserves to probe ever more deeply into the earth for new sources. They are also venturing into provinces such as Quebec and New Brunswick where governments and the public have not had much, if any, experience with exploration for petroleum reserves. And that unfamiliarity, as much as anything, may account for much of the opposition to fracking, which means it may take years before public apprehensions disa pear.
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|Title Annotation:||CHEMICAL ENGINEERING: HYDRAULIC FRACTURING|
|Publication:||Canadian Chemical News|
|Article Type:||Cover story|
|Date:||Jan 1, 2012|
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