Proximity of Precambrian basement affects the likelihood of induced seismicity in the Appalachian, Illinois, and Williston basins

Rob Skoumal, Michael Brudzinski, & Brian Currie

Published August 25, 2016, SCEC Contribution #6570, 2016 SCEC Annual Meeting Poster #189

While most of the induced seismicity observed in the Central and Eastern U.S. has occurred in sedimentary basins that have experienced overall increases in oil and gas development (e.g., the Anadarko and Ft. Worth basins), other basins with similar activity (e.g., the Williston and Northern Appalachian basins) have experienced very little, if any, induced seismicity. While hydro-geomechanical modeling indicates that induced seismicity may be related to the proximity of critically stressed faults in the crystalline basement, recent studies have found fluid injection rate to be the dominant factor controlling induced seismicity. To test these interpretations, we evaluated water disposal and well completion records from the Appalachian, Illinois, and Williston basins, and compared them with induced seismic sequences identified through seismic template matching of all cataloged earthquakes in these regions. Our results indicate a strong correspondence between induced seismic events and the proximity of subsurface wastewater injection/hydraulic fracturing targets to crystalline basement rocks. For example, in the Northern Appalachian Basin, of the >20 identified induced seismic sequences, all but two were associated with injection/completion targets located at depths within ~1 km of the basement. In parts of the basin where target intervals are at depths >1 km from basement, induced events have been recorded only in proximity to basement-involved faults. In the Williston Basin, most disposal interval/hydraulic fracturing targets are >1 km above the crystalline basement which may explain the lack of induced seismic events in the region despite high rate fluid injection. Collectively, the results of our investigation suggest that proximity to basement is an important variable in considering the likelihood of induced seismicity associated with wastewater disposal and hydraulic fracturing.

Key Words
Induced seismicity, wastewater disposal, hydraulic fracturing

Skoumal, R., Brudzinski, M., & Currie, B. (2016, 08). Proximity of Precambrian basement affects the likelihood of induced seismicity in the Appalachian, Illinois, and Williston basins. Poster Presentation at 2016 SCEC Annual Meeting.

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