EDMONTON, A.B. — A new study from the University of Alberta is suggesting that fracking and frackwater disposal both have limited impacts on seismic events.
Geophysicist Mirko Van der Baan and his team spent the past two years examining earthquake rates over the past 30 to 50 years in North Dakota, Ohio, Oklahoma, Pennsylvania, Texas, West Virginia, Alberta, British Columbia, and Saskatchewan.
According to the study, scientists found no province- or state-wide correlation between increased hydrocarbon production and seismicity. They also discovered that human-induced seismicity is less likely in areas that have fewer natural earthquakes.
However, Dr. Van der Baan’s team found that Oklahoma was an anomaly, where seismic rates have changed dramatically in the last five years, with a strong correlation to saltwater disposal.
“It’s not as simple as saying ‘we do a hydraulic fracturing treatment, and therefore we are going to cause felt seismicity.’ It’s actually the opposite. Most of it is perfectly safe,” said Van der Baan, who is also director of the Microseismicity Industry Consortium. The Consortium is funded by such companies as Shell, Chevron, and Husky Energy.
“What we need to know first is where seismicity is changing as it relates to hydraulic fracturing or saltwater disposal. The next question is why is it changing in some areas and not others,” continued Van der Baan. “If we can understand why seismicity changes, then we can start thinking about mitigation strategies.”
Though Van der Baan noted that hydraulic fracturing has been in practice since the 1950s, it has come under increased scrutiny in the last number of years due to both increased production and the use of increased treatment volumes. He said an important next step will be continued monitoring.
“Hydraulic fracturing is not going away. The important thing is that we need to find the balance between the economic impact and environmental sustainability of any industry,” he said.
The study also contradicts another study conducted by researchers at the University of Calgary that was released last year. That study found that fracking triggered a series of earthquakes in the Fox Creek area in January, 2015.
“Human-induced seismicity and large-scale hydrocarbon production in the USA and Canada” was published in the scientific journal Geochemistry, Geophysics, Geosystems.