A preliminary study of CO2 hydrate formation rate in shallow seabed using numerical evaluation

Abstract

Previous research on Carbon capture and storage (CCS) below the ocean floor focuses on utilizing the negative buoyancy zone (NBZ) of liquid CO2 for storage stability. Reaching the NBZ requires CO2 injection under 3km depth with high pressure. The formation of CO2 hydrate under low temperature and high-pressure conditions was also investigated as an alternative stabilization method. In this scenario, CO2 hydrate functions as a storage material and an artificial entrapment to prevent CO2 escape. CO2 hydrate storage forming near 500m depth is a more cost-effective and adaptable than NBZ storage. This study performs preliminary research on the viability of CO2 sequestration by hydrate formation in shallow sub-seabed. The conversion rate of CO2 to hydrate under varying initial seabed permeability is evaluated by performing a thermal-hydraulic coupled simulation using FLAC. Consequently, it is expected to contribute to developing an alternative to CO2 hydrate formation as CCS.