CO2 sequestration in depleted methane hydrate sandy reservoirs

CO2 sequestration technology is crucial for carbon capture and storage (CCS). This study explores the sequestration behavior of CO2 as a hydrate in depleted methane hydrate (MH)-bearing sediments. MH formation and dissociation, CO2 injection, and water injection processes are experimentally simulated using glass beads to evaluate the entire technological process. The effects of different parameters on CO2 hydrate formation are analyzed to evaluate hydrate-based CO2 sequestration technologies. The aqueous water distribution minimally changes during the gas hydrate formation and dissociation in this study. For all the cases considered, local hydrate formation channels are not generated at the axis or wall of the vessel during the CO2 injection process. The saturation of the CO2 hydrate and residual water after the CO2 hydrate formation is proportional to the initial reservoir water saturation. This is the first study to propose water injection to promote the formation of CO2 hydrates, which are beneficial for CO2 sequestration. The amount of injected water decreases as the CO2 hydrate saturation increases before the water injection. A qualitative analysis indicates increased formation of CO2 hydrates during the water injection and promotion of the CO2 sequestration.