Earthquakes Induced by Hydraulic Fracturing Are Pervasive in Oklahoma

• Published in: Journal of geophysical research. Solid earth Vol. 123; no. 12; pp. 10,918 - 10,935
• Main Authors: Skoumal, Robert J., Ries, Rosamiel, Brudzinski, Michael R., Barbour, Andrew J., Currie, Brian S.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-12-2018
• Subjects: Correlation; Earthquakes; Geological hazards; Geophysics; Hydraulic fracturing; Identification; induced seismicity; Modelling; Oklahoma; Pore pressure; Pressure effects; Regions; Seismic activity; Seismic hazard; Seismicity; State regulations; Template matching; Wastewater; Wastewater disposal; Wells; United States > US; Oklahoma
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1029/2018JB016790

Wastewater disposal is generally accepted to be the primary cause of the increased seismicity rate in Oklahoma within the past decade, but no statewide analysis has investigated the contribution of hydraulic fracturing (HF) to the observed seismicity or the seismic hazard. Utilizing an enhanced seismicity catalog generated with multistation template matching from 2010 to 2016 and all available hydraulic fracturing information, we identified 274 HF wells that are spatiotemporally correlated with bursts of seismicity. The majority of HF‐induced seismicity cases occurred in the SCOOP/STACK plays, but we also identified prominent cases in the Arkoma Basin and some more complex potential cases along the edge of the Anadarko Platform. For HF treatments where we have access to injection parameters, modeling suggests that poroelastic stresses are likely responsible for seismicity, but we cannot rule out direct pore pressure effects as a contributing factor. In all of the 16 regions we identified, ≥75% of the seismicity correlated with reported HF wells. In some regions, >95% of seismicity correlated with HF wells and >50% of the HF wells correlated with seismicity. Overall, we found ~700 HF‐induced earthquakes with M ≥ 2.0, including 12 events with M 3.0–3.5. These findings suggest state regulations implemented in 2018 that require operators in the SCOOP/STACK plays to take action if a M > 2 earthquake could have a significant impact on future operations.
Key Points
Recent seismicity in Oklahoma is primarily induced by wastewater disposal, but hydraulic fracturing has also directly induced earthquakes
Using all available stimulation data and an improved earthquake catalog, we identify earthquakes induced by hydraulic fracturing
Between 2010 and 2016, ~700 earthquakes with M 2.0–3.5 are best explained as being induced by hydraulic fracturing