Assimilation Of Microseismic Data Into Coupled Flow And Geomechanics Models

Abstract

Geologic CO2 storage in deep saline aquifers requires reliable risk assessment to evaluate and minimize unintended consequences such as potential CO2 leakage and induced seismicity. To mitigate such risks continuous monitoring and model updating is needed to improve future predictions and risk assessment. Injection-induced microseismicity has been proposed as a monitoring technique that can be used to constrain rock flow and mechanical properties. We present our ongoing work to develop a framework for assimilation of microseismic monitoring data for estimation of rock mechanical properties using coupled flow and geomechanics simulation as a forward model. Coupled flow and geomechanics simulation is combined with Mohr-Coulomb failure criterion and a stochastic measurement model, to provide a rigorous approach for prediction and interpretation of spatiotemporal distribution of discrete microseismic events in the formation. The focus of the paper is on building a geomechanics-based stochastic framework that can be used to establish physical correlation among rock mechanical properties and microseismic response data. The resulting correlations can then be used to estimate rock properties from observed microseismic clouds. In this paper, we present the developed framework and preliminary results to evaluate its performance for integration of microseismic data.