Provincial regulators are struggling to keep up with a fracking boom that has caused small earthquakes in British Columbia and Alberta and could result in a larger one in the future, one of Canada's top experts on seismic risks said on Thursday.
British Columbia's Oil and Gas Commission confirmed this week that a 4.6-magnitude earthquake in the shale gas fields of the province's northeast last summer was caused by hydraulic fracturing, the industry practice of using high-pressure water to crack rock and extract natural gas or oil.
The quake – which shook workers but caused no damage – illustrates the need for more monitoring and better risk assessment, geophysicist Gail Atkinson, professor at the University of Western Ontario, said in an interview on Thursday.
"I do think the industry is on the right track, but we need to keep working with them closely and keep on them to keep moving," said Dr. Atkinson.
Dr. Atkinson holds a national research chair in hazards from induced seismicity.
"In the long run, we'd like to be able to understand what is going on and control and mitigate events before they happen. We need to make sure that we don't end up with a large event in a location where it could cause damage."
The summer earthquake surpassed two induced earthquakes of 4.4 magnitude in Alberta and one of similar magnitude in B.C. last year that have been attributed to gas drilling activities, adding to growing concerns about the controversial extraction process, commonly known as fracking.
The technology has allowed prolific development of unconventional oil and gas fields that have revolutionized the industry across North America, and changed the global oil business. U.S. oil production has soared by 80 per cent since 2009, from 5.3 million barrels a day to 9.3 million this month, while North American natural gas supply has seen a similar growth.
But critics say intensive fracking raises risks of groundwater contamination, methane leaks and induced seismic activity.
Industry-caused earthquakes have been registered in several U.S. states, including Ohio, Texas and Oklahoma, as well as in Britain and the two western provinces. Often they occur when companies inject large volumes of waste water under ground, but in mountainous oil- and gas-fields of British Columbia and Alberta, the seismic activity has occurred as a result of the fracking process itself.
A 2014 study by the Geological Survey of Canada found that in northeast B.C., 24 earthquakes occurred in 2002-03, before hydraulic fracturing started in the area. From 2006-09, with light-to-moderate fracking taking place, there were 146 earthquakes. In 2010-11, with fracking activity peaking, there were 189 quakes.
In B.C. and Alberta, any quakes at magnitude 4.0 or above that are related to fracking trigger an immediate shutdown until a mitigation plan can be worked out and approved by regulators. "The operator has to stop, contact us and come up with a mitigation plan before they can proceed and then, of course, we'll monitor that ever so much more closely from then on," said Ken Paulson, chief operating officer of the BC Oil and Gas Commission.
The Canadian Association of Petroleum Producers has voluntary guidelines that urge companies to assess the risk of seismic activity before drilling, and to adjust pressure and water volumes in the fracking operation to reduce risks.
However, in Oklahoma, where high-volume waste-water injection has caused quakes, regulators have imposed even tougher rules. There, producers wanting a drilling permit must submit geological evidence that assesses seismic conditions. A permit will not be issued if conditions are deemed too risky. Under a "yellow light" permit, the operators can work for only six months, must shut down the well every 60 days to take specific pressure readings, and must stop if they encounter a prescribed level of seismic activity.
Dr. Atkinson said the voluntary approach is insufficient.
"It is my opinion that regulators do have a role to play in encouraging good practice and creating a level playing field, and that regulations around good practice and monitoring are probably good for everyone, including operators," she said.