Monitoring CO۲ injection in shale gas reservoir through cross well seismic and electromagnetic tomography

Carbon dioxide (CO₂) injection, also known as geological carbon sequestration or carbon capture and storage, is a critical strategy for mitigating anthropogenic CO₂ emissions and their subsequent impact on the physical and petrophysical properties of subsurface formations. Shale gas reservoirs are receiving increased attention, with CO₂ injection emerging as a leading technology for enhancing gas recovery and achieving carbon storage. This study employs cross-well tomography, incorporating both seismic and electromagnetic (EM) methods, to monitor the CO₂ injection process within a synthetic shale gas reservoir model. The methodology utilizes time-lapse cross-well tomography data acquired before and after CO₂ injection. Seismic P-wave velocity (Vp) and electrical resistivity (ρ) serve as key physical parameters in detecting CO₂ distribution. A mixed-norm inversion technique is applied to improve the resolution and accuracy of recovered models. The results demonstrate that seismic tomography is effective in delineating changes in P-wave velocity associated with CO₂ saturation, while electromagnetic tomography captures resistivity variations indicative of CO₂ migration. Integrated seismic-EM tomography provides a comprehensive framework for monitoring CO₂ injection, enhancing the reliability of long-term carbon storage assessments.

Keywords:

Co۲ Injection , Cross-hole tomography , Seismic tomography , electromagnetic tomography , mixed-norm inversion