Study: Fracing, saltwater disposal have limited seismic impact

Research from a University of Alberta geophysicist suggests hydraulic fracturing and saltwater disposal have limited impact on seismic events.

A team of researchers led by Mirko Van der Baan found no state- or province-wide correlation between increased hydrocarbon production and seismicity after reviewing 30-50 years of earthquake rates from US states North Dakota, Ohio, Pennsylvania, Texas, West Virginia, and Canadian provinces Alberta, British Columbia, and Saskatchewan.

They also discovered that human-induced seismicity is less likely in areas where fewer natural earthquakes occur.

The lone exception was Oklahoma, where seismicity rates have changed dramatically in the last 5 years, with strong correlation to saltwater disposal related to increased hydrocarbon production (OGJ, June 19, 2017, p. 23).

“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 also is director of the Microseismicity Industry Consortium, a novel, applied-research geophysical initiative.

“What we need to know first is where seismicity is changing as it relates to hydraulic fracturing or saltwater disposal,” continued Van der Baan. “The next question is why is it changing in some areas and not others? If we can understand why seismicity changes, then we can start thinking about mitigation strategies.”

A next step, he believes, will be continued monitoring. “Hydraulic fracturing is not going away,” Van der Baan said. “The important thing is that we need to find the balance between the economic impact and environmental sustainability of any industry.”