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Exploring the Impact of Operational Management Strategies on the Evolution of Induced Seismicity

Kayla Kroll, Elizabeth S. Cochran, & Christopher S. Sherman

Submitted September 10, 2023, SCEC Contribution #12922, 2023 SCEC Annual Meeting Poster #210

Understanding the relationship between operational controls at carbon storage sites are becoming increasingly important as these technologies are rolled out on a global scale. Carbon storage operators have a limited number of reliable mitigation tools with which to mitigate induced seismic events, despite our general understanding of the mechanisms that control induced events. Modulation of the injection rate is among the only reservoir engineering strategies for mitigating induced earthquakes. Possible injection scenarios include injection at nearly constant injection rates or variable injection rates with time to accommodate the changing influx of waste fluids, injection well workovers, or to allow pressure dissipation in the reservoir. Both methods have been associated with high rates of induced earthquakes (e.g. the Illinois Basin Decatur Project and the Paradox Valley Saline Disposal Operation). Other proposed strategies (which are perhaps more reasonable for geothermal or carbon storage than for wastewater disposal) include actively managing pressures through co- or pre-production of fluids, initially high injection rates followed by sequential reduction, or even complete cessation of injection. In this work, we use 3D physics-based earthquake simulations to understand the impact of variable injection strategies under the condition that the same total volume of fluid has to be injected within a given time period. We examine the influence of different injection strategies on induced earthquake rates, maximum event magnitudes, and post-injection seismicity. In general, we find that variable-rate injection leads to more frequent and larger magnitude events than constant-rate injection. Further, we find that cycling injection rates tends to have a significant portion of the events during the shut-in periods and those event rates decay slower when compared to constant rate injection. Finally, we find that ramping down injection rates slowly is most effective at reducing post-shut-in seismicity rates.

Kroll, K., Cochran, E. S., & Sherman, C. S. (2023, 09). Exploring the Impact of Operational Management Strategies on the Evolution of Induced Seismicity. Poster Presentation at 2023 SCEC Annual Meeting.

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Computational Science (CS)