Experimental investigation of CO2 hydrate formation kinetics in silt-clay-sand marine sediments for carbon sequestration

Silt, as one of the most porous mediums in marine environments, plays a critical role in gas hydrate formation. Hydrate-based CO2 sequestration in marine sediments is a highly promising technology due to the stability and exceptional storage capacity of CO2 hydrates. However, while previous studies have extensively explored the formation and properties of CO2 hydrates in sandy and clayey sediments, there remains a significant gap in understanding the formation kinetics of CO2 hydrates in sediments containing silt. This study investigates the pressure−temperature changes, formation kinetics, and storage capacity of CO2 hydrates in silty sediments mixed separately with clay and sand. Experiments were conducted under controlled conditions of 5.5 MPa and 1.3 °C in a reactor equipped with nine temperature sensors to accurately monitor the process. The results demonstrate that sandy sediments exhibit higher CO2 hydrate saturation and greater CO2 consumption compared to clayey sediments. Notably, in sandy reservoirs with high silt content, CO2 hydrate formation exhibits enhanced kinetics and sequestration efficiency, highlighting their superior suitability for hydrate-based CO2 sequestration in marine environments. The findings of this work provide novel insight into the role of silt in CO2 hydrate formation dynamics, offering valuable implications for advancing sustainable CO2 sequestration technologies in marine sediments. This study addresses a critical research gap and contributes to optimizing strategies for efficient and environmentally safe CO2 storage.