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ON FRACKING, EGS, AND QUAKES
MOTHER NATURE DOESN’T take kindly to poking, even when administered with the best of intentions. Science has documented that the extraction of petroleum or natural gas by fracturing subterranean rock with high-pressure injections (fracking) can induce earthquakes. Even Enhanced Geothermal Systems, easier on the environment than fossil fuels, have been found to cause quakes. Here are tidbits on these seismic risks, assembled from Science, published weekly by the American Association for the Advancement of Science, together with my usual Internet sleuthing.
More Production = Tradeoffs. Output from existing oil and gas fields has been increased through enhanced recovery methods. This increase is one reason that world oil prices per barrel have dropped from December 1979’s $125.230 and June 2008’s peak of $145.93 to today’s fluctuation around $50.
Tradeoffs of enhanced drilling for petroleum and oil have been well documented: For example, in “Drilling for Earthquakes,” Scientific American, March 2018, Anna Kuchment writes, “Earthquake rates in Oklahoma and Texas have skyrocketed since 2008. The cause, scientists say, is injecting wastewater from oil and gas operations into deep underwater wells.”
Image credited to The Voorhes from Scientific American, March 2018.
Note, this isn’t fracking per se; it’s a byproduct of the operations’ wastewater disposal.
Other research points to fracking itself as the culprit: Canadian researchers identified “Fault Activation by Hydraulic Fracturing in Western Canada.” Xuewei Bao and David W. Eaton, Department of Geoscience, University of Calgary, Calgary, Alberta, write: “Hydraulic fracturing has been inferred to trigger the majority of injection-induced earthquakes in western Canada, in contrast to the Midwestern United States, where massive saltwater disposal is the dominant triggering mechanism.”
Either way, Mother Nature doesn’t think much of enhanced-recovery technology.
Geothermal is Green. You’d think Mother Nature would like geothermal energy. “Geotherm Energy” offered the basics here at SimanaitisSays. In theory, the U.S. could supply the world’s energy needs for the next 30,000 years. On the other hand, it’s expensive technology to develop and maintain.
Traditional geothermal energy taps naturally permeable sources of subterranean heat. “Managing Injection-Induced Seismic Risks,” by Kang-Kun Lee, et al, in Science, May 24, 2019, addresses the quandary: “Because naturally permeable systems are rare,” the researchers write, “enhanced geothermal system (EGS) technology stimulates the creation of permeable pathways in otherwise impermeable rock by injection of water under high pressure, creating new fractures and causing preexisting fractures to open.”
Think of it as “fracking for heat.”
In 2017, an EGS project in Pohang, South Korea, was begun, creating an artificial geothermal reservoir within low-permeability crystalline rock by hydraulically fracturing a connected network between two wells.
Image from Science, May 24, 2019.
EGS Tradeoff. Lee, et al continue, “On the afternoon of November 15, 2017, the half-million residents of Pohang experienced violent shaking in an Mw 5.5 earthquake. The earthquake injured 135 residents, displaced more than 1700 people into emergency housing, and caused more than $75 million (USD) in direct damages to more than 57,000 structures and more than $300 million of total economic impact, as estimated by the Bank of Korea.”
Image by Yonhap/EPA-EFE/Shutterstock from Science, May 24, 2019.
Mother Nature was not amused.
Risk Assessment. “Fracking does not appear to cause large earthquakes in many other areas that are prone to induced seismicity,” the Canadian researchers Bao and Eaton observe. However, they note, “Understanding the underlying causes of seismicity in different locales is vital for developing sound regulation to limit damaging earthquakes.”
Lee, et al note, “The Pohang experience emphasizes the critical importance of formal processes of risk assessment and ongoing review that involve responsible authorities and appropriate independent oversight and scrutiny.”
This goes either way, whether we’re poking Mother Nature for Good or for Evil. ds
© Dennis Simanaitis, SimanaitisSays.com, 2019
Simanaitis Says 
Interesting story. Similar things happen at The Geysers in California – one of the biggest geothermal electric fields in the world. As far back as the 1980s. a constant background of micro (and sometimes felt) quakes was associated with the field, modulated somewhat by the rate at which steam was extracted and condensate injected. After a while, the field output began to decline – it needed recharge. So sewage effluent was piped from Lake County and, later, Santa Rosa for that. Now, there are clusters of sometimes quite noticeable earthquakes that are closely related to the location and rate of sewage injection. The field production has stabilized.