Monitoring of CO2 geological storage based on the passive surface waves

Carbon dioxide (CO₂) capture and geological storage (CCS) is one of promising technologies for greenhouse gas effect mitigation. Many geotechnical challenges remain during carbon dioxide storage field practices, among which effectively detecting CO₂ from deep underground is one of engineering problems. This paper reviews monitoring techniques currently used during CO₂ injection and storage. A method developed based on measuring seismic microtremors is of main interest. This method was first successfully used to characterize a site in this paper. To explore its feasibility in CO₂ storage monitoring, numerical simulations were conducted to investigate detectable changes in elastic wave signatures due to injection and geological storage of CO₂. It is found that, although it is effective for shallow earth profile estimation, the surface wave velocity is not sensitive to the CO₂ layer physical parameter variations, especially for a thin CO₂ geological storage layer in a deep underground reservoir.