Cross-Well Imaging for Monitoring CO2 Plumes at Svelvik CO2 Field Lab

Effective and secure underground storage of CO2 requires comprehensive monitoring techniques to track plume migration, prevent fluid leakage, and support operational decisions. Among various monitoring techniques, time-lapse cross-well imaging method offers advantages such as high signal-to-noise ratio and high survey repeatability, thereby enhancing the monitoring reliability. In this study, we propose an advanced cross-well imaging approach to enhance the resolution and fidelity of CO2 plume monitoring. This approach integrates reverse time migration with an energy norm (inverse scattering) imaging condition, leveraging the often stronger transmitted energy with higher-frequency information to produce high-resolution structural images. We also include a pseudo-Hessian correction to mitigate amplitude distortions caused by uneven illumination, geometrical spreading, and subsurface heterogeneity. The proposed method is applied to cross-well datasets acquired during the October 2023 CO2 injection campaign at the Svelvik CO2 Field Lab, which is a laboratory for studying CO2 monitoring technologies. The imaging results reveal four distinct anomalies associated with the injected CO2.