Disposal of fracking waste induces earthquakes, study suggests, signaling dangers for Northern BC
More and more studies are finding earthquakes common in areas where shale gas development is booming. An increase in tremors in northeastern BC leads the provincial and federal government to investigate.
A new Texas study reports that shale gas projects induce earthquakes.
The study by Texan seismologist Cliff Frohlich found that small earthquakes near injection wells in Texas were more common than previously recorded, strengthening a growing scientific consensus that the shale gas industry is inducing earthquakes.
The study gives British Columbians another reason to worry about the burgeoning industry as shale gas boom-towns of northeastern BC have experienced more frequent earthquakes.
“It’s one more log on the fire,” University of Victoria environmental studies professor Karena Shaw, who co-authored a paper on BC’s shale gas industry for the Canadian Political Science Review, said.
Between 2009 and 2011, more than 30 earthquakes have shaken the Horn River Shale basin in northeastern BC, where hydraulic fracturing or "fracking" occurs. Earthquakes reached 4.3 magnitude in some cases.
Concerns over the unprecedented number of earthquakes in the region sparked a provincial investigation into whether the tremors could be linked to shale gas activities in the region.
“We expect to have the investigation complete and findings released in the coming months,” communications coordinator Maria Reschke of the BC Oil and Gas Commission told The Vancouver Observer.
In fracking research, Canada lags behind
So far, Canada lags behind other countries taking the lead on research into impacts of the relatively new shale gas industry and its potential to induce earthquakes. Studies have been released in the United States and the United Kingdom. France has banned the controversial shale gas extraction technique, until further scientific study can be completed.
Shaw believes these latest findings by Frohlich could further calls for stricter regulation of the shale gas industry.
Northern British Columbians have concerns about potential water contamination from the process of extracting shale gas, concerns fueled by documentaries such as Gasland and Burning Water. In Gasland, water from kitchen taps near Pennsylvania’s heavily drilled Marcellus Shale basin burst into flames. In Burning Water, Albertan farmers battle for their homes against natural gas giant Encana.
Now the increasing number of earthquakes in areas steeped in shale gas production add another problem for industry and regulators to address, reflecting the absence of a really robust regulatory framework, Shaw said.
Fracking fluids make for slippy fault lines
Shale gas refers to natural gas trapped between fine-grained rocks underground. To extract it, the industry uses hydraulic fracturing processes, blasting high volumes of water and toxic chemicals into the ground to free up the gas.
Facking, while not new, became more common in the past decade. This technique combined with the new process of horizontal drilling has allowed the natural gas industry to access gas in previously unreachable underground basins.
Scientists like Frohlich believe that earthquakes are rarely caused by the hydraulic fracturing process itself, but more often by the efforts to dispose of the water and chemicals needed to free up the gas.
The waste water or “fracking fluid” is often pumped into injection wells, where it can travel distances of between one and five kilometres towards a fault line.
“Faults are everywhere,” he said, adding that if the fluid reaches a stuck fault it can reduce the friction and cause it to slip.
Frohlich found that all the small earthquakes he could locate accurately in Texas’ Barnett Shale basin were near injection wells with high volumes of waste fluid, some with the State’s maximum 150,000 barrels per month.
Last year, the Arkansas Geological Survey found that as the volume and pressure of fracking fluid injected into the ground increased, so did the magnitude of earthquakes in the area, with one reaching 4.7 in magnitude.
Most are small and harmless, Frohlich said - no bigger than earthquakes that would occur naturally, ranging in magnitude from 1.5 to 2.5.
While Frolich said he doesn't believe that the small earthquakes occurring in Texas are a public health hazard, he sees his study as a stepping stone for further scientific study needed on the issue, the lack of which is heightening public concern.
“These things haven’t been studied very well in an era where there are tremendous calls for regulation from the government,” he said.
Could small shakes bring bigger quakes?
Frohlich’s study comes on the heels of a major report by the U.S. National Research Council released in June.
The report said that “hydraulic fracturing has a low risk for inducing earthquakes that can be felt by people, but underground injection of waste-water produced by hydraulic fracturing and other energy technologies has a higher risk of causing such earthquakes.”
Earthquakes have been frequent near shale gas developments in Colorado, Arkansas, Ohio, Oklahoma and the United Kingdom.
The question is whether these relatively small quakes could trigger greater more destructive ones.
"One can never say never," Frohlich said. But the past 50 years of research on human-induced earthquakes indicates no pattern that little induced earthquakes can build up and become dangerous big ones." So far the largest injection-induced earthquake reached a magnitude of 5.6.
However, the NRC report said the frequency of earthquakes could increase due to expanding shale gas development.
Federal environment minister Peter Kent launches environmental review of shale gas
The Canadian Association of Petroleum Producer’s vice-president for operations, David Pryce, noted that disposing of waste-water deep underground is a common practice that’s been used since the first days of the oil and gas industry.
“The practice has been used safely in Canada for many decades, and it is governed by strict regulations,” Pryce told The Vancouver Observer.
Reschke of the BC’s Oil and Gas Commission stated that regulations are in place to ensure injected fluids do not migrate into other formations where it may be detrimental to hydrocarbon recovery or become an overpressure drilling safety hazard for future wells.
“In terms of the safe and stable operation of injection wells, British Columbia has laws in place that regulate the pressure of target formations to stay safely below pressure that would cause fracturing,” wrote Reschke in an email.
Frohlich speculates that the reason we are now seeing more earthquakes induced by injection wells is because industry is developing in previously undisturbed territory.
Minister Kent launched a review of the environmental impacts of hydraulic fracturing in September 2011. The review, undertaken by a panel of experts at the Council of Canadian Academies, is expected to take between 18 and 24 months to complete. The panel will hold their second meeting at the end of August.