Modeling Approach for Evaluating Time-Lapse Effects of CO2 Storage on Particle Velocity and Strain Rate Data

Abstract

Summary Carbon capture and storage (CCS) is a crucial component in reducing greenhouse gases in the atmosphere. To make CCS attractive and ensure control and safety, monitoring solutions are needed capable of measuring subsurface effects of storage operations. Distributed acoustic sensing (DAS) can play a pivotal role as an alternative to conventional seismic monitoring. Here, we present results of a forward modeling approach for calculating seismic time lapse effects of CO2 injection in reservoirs on particle velocity and strain rate data, respectively equivalent to geophone and DAS data. The developed modelling approach is capable of efficiently simulating the time lapse effect of CO2 injection, while accounting for realistic field noise levels. To overcome the angle sensitivity of the DAS cable we recommend an orthogonal cable layout combined with analysis of multiple seismic phases (P and S) is recommended. The approach can help to support the design of the monitoring layouts and tune this to the specific target to be monitored. In a next step, quantitative information derived from seismic phases can be used to invert for changes in reservoir properties.