FRACKING RAISES B.C. QUAKE RISK
Report links oil and gas activity to more than 90 per cent of quakes in an area on the B.C.-Alberta border
Scientists from the federal government, regulatory agencies and Canadian universities have unearthed a deeper understanding of the link between fracking and earthquakes in a major oil-and-gas-producing region of Western Canada.
A new report, set to be published in the journal of the Seismological Society of America, examines an area straddling the B.C.-Alberta border and finds that between 90 and 95 per cent of seismic activity Magnitude 3 or larger in the last five years was caused by oil and gas activity, with most of it linked to hydraulic fracturing or “fracking.”
“The biggest implication of this study is that we can no longer deny the link between induced earthquakes and hydraulic fracturing,” said Honn Kao, an earthquake seismologist with the Geological Survey of Canada and coauthor of the report. Asked if more work is needed to better understand the link between seismic activity and resource extraction in Western Canada, Kao said: “The answer is definitely yes. “We now know much more about induced seismicity than four years ago when our research project started. But we still have a long way to go before we can claim that the phenomenon is well-understood,” said Kao, a B.C.-based scientist with Natural Resources Canada, a federal government institution.
“Ultimately, we hope that our research results can provide observation-based results to regulators so that a good balance can be reached between the protection of public safety and environment, and the economic benefit of developing unconventional oil and gas resources,” he said.
The process of fracking uses high-pressure injections of water, sand and chemicals to break apart rock and release oil and natural gas trapped underground. The practice has become more widespread in B.C. in recent years.
For the report, in the May-June edition of Seismological Research Letters, the team of 13 scientists surveyed seismic activity between 1985 and 2015 in the Western Canada Sedimentary Basin (WCSB) — an area of 454,000 square kilometres covering Alberta and parts of B.C., Saskatchewan and Manitoba — and looked at 12,289 fracking wells and 1,236 waste-water disposal wells.
The report notes between 2010 and 2015, “both seismicity rates and the number of HF (fracking) wells rose sharply,” adding: “It is remarkable that, since 1985, most of the observed M=3 seismicity (activity of Magnitude 3 or greater) in the WCSB appears to be associated with oil and gas activity.”
Another co-author of the report is Dan Walker, senior petroleum geologist with the B.C. Oil & Gas Commission. Walker wasn’t available to speak Monday, but BCOGC spokesman Graham Currie answered questions by email, saying: “The B.C. Oil and Gas Commission has taken a leading role in the detection and mitigation of induced seismicity.”
There’s nothing to suggest increased oil and gas activity represents any elevated risk for the public, Currie said, noting northeast B.C. doesn’t have a history of “high-magnitude events,” and “the commission has effective regulatory measures that apply to every well approved in northeast B.C. to ensure there is no risk to the safety of the public.”
The report’s lead author, Western University professor of geophysics Gail M. Atkinson, said it’s important to note earthquakes triggered by fracking are localized within a few kilometres of drilling sites, which are usually in remote locations, and people in B.C.’s cities and towns aren’t at risk.
But, she added, the new findings “fundamentally change” our understanding of the seismic hazard in these regions, and could have significance for industry workplace safety, and could change seismic risk calculations for critical infrastructure such as bridges and dams.
“Previous hazard assessments, essentially, are too low,” she said.
The report is “an important step,” Atkinson said, in understanding the link between fracking and seismic activity.
“There hasn’t been a comprehensive, statistical report of how many earthquakes are happening each year and what percentage of them are related to hydraulic fracturing,” she said.
“There’s been this growing tide over the last few years” of oneoff reports linking an earthquake with fracking activity, she said, but this new report puts them “all together in a more systematic way.”
“We now know much more about induced seismicity than four years ago when our research project started. But we still have a long way to go before we can claim that the phenomenon is well-understood.” — Honn Kao