Abstract:

Induced seismicity presents a significant risk for carbon sequestration in low-permeability fractured formations because even small-magnitude earthquakes and slip on pre-existing fractures threaten the integrity of the seal of CO2 repositories. High-resolution wellbore images allow identification of both natural discontinuities and drilling-induced failures indicative of in-situ stress orientation. Combined with other geophysical logs, images allow for evaluation of geomechanical properties and facilitate modeling of effective stress perturbation due to CO2 injection. In this study we review borehole techniques for stress analysis and discuss their application for a potential CO2-storage site in the northern Newark basin in the northeastern U.S. Parts of the basin are located near the New York Metropolitan area, therefore, assessing induced seismicity risk is critical for this site. Preliminary analysis suggests reverse faulting/strike-slip stress regime but indicates that a more accurate estimate of the least horizontal stress is needed for evaluating the permissible range of injection pressure. Potential risks and implications for carbon storage at this locality are discussed, followed by suggested future work.

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