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A new study aiming to provide a better understanding of how injection wells in the U.S. influence earthquake activity cites wastewater injection rate as a critical factor. In the study, the highest-rate wastewater disposal wells analyzed were nearly twice as likely to be associated with earthquake events compared to their lower-rate counterparts. Earthquakes can be induced by industrial processes, a fact established decades ago. Since 2009, when seismicity in the U.S. midcontinent began to surge, earthquakes induced by the underground fluid injection processes associated with oil and gas extraction have become a major focus. Previous work evaluating a relationship between quake activity and injection wells has been site-specific, focusing on wells in close proximity to distinct quakes. Here, to investigate the induced earthquake phenomenon more broadly with the aim of better understanding the possibility of induced seismicity associated with any given injection well, M. Weingarten et al. leveraged publically available data on operational wells across the central and eastern U.S. They analyzed a range of operational differences between these wells, both those associated with earthquakes and those that were not, discovering that, of the several well-related parameters hypothesized to trigger an induced quake event (including cumulative injected volume of wastewater and wellhead injection pressure), only injection rate showed a strong correlation. While the authors acknowledge that other factors besides injection rate -- like the regional state of stress -- could also play a role in a well's likelihood of triggering an earthquake, they suggest injection rate is an important parameter that could be used by the oil and gas industry to lower the likelihood of damaging earthquake events.
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Article #10: "High-rate injection is associated with the increase in U.S. mid-continent seismicity," by M. Weingarten; S. Ge at University of Colorado in Boulder, CO; J.W. Godt at United States Geological Survey in Denver, CO; B.A. Bekins; J.L. Rubinstein at United States Geological Survey in Menlo Park, CA.
Science