ASSESSING INDUCED SEISMICITY RISK ASSOCIATED WITH CO2 GEOLOGIC SEQUESTRATION

Recent seismic activity in the mid-continent US has raised concern about the potential for inducing earthquakes due to CO₂ injection in the subsurface for sequestration purposes. Geomechanical principles and techniques, which provide a theoretical framework for addressing the risk of induced seismicity, are presented. These are coupled with field based data of reservoir petrohysical properties, injectivity tests, fault architecture, rock strength, and geophysical log information, to estimate the potential for fault slippage. Scaling relationship is used to relate fault size and the expected magnitude of seismic severity in the event of fault movement. Additionally, to prepare for commercial scale CO₂ sequestration activities in Kansas, a state wide approach to determine the critical induced pressure threshold for preventing fractures in the caprock and injection zone, as mandated by EPA Underground Injection Control Class VI rules, is presented.