Carbon Dioxide Hydrate Kinetics in Porous Media with Montmorillonite Suspensions: A Study on Behavior and Interactions

Carbon dioxide sequestration in oceanic saline aquifers via solid hydrates is a promising method for mitigating the greenhouse effect. Clay, a primary constituent of marine sediments, significantly impacts the hydrate kinetics. Here, low-field nuclear magnetic resonance was used to monitor carbon dioxide hydrate kinetics within porous media in montmorillonite suspensions with different concentrations. The results showed that the clays were stable in the suspensions, generating an electric field and affecting hydrate kinetics. During hydrate formation: hydrates formed preferentially in large pores, while water in small pores was restricted. In the presence of montmorillonite, the water conversion rate increased, and the sites of hydrate growth shifted. This may be due to additional nucleation sites and enhanced water molecule activity influenced by montmorillonite. During hydrate dissociation: the process was accompanied by the migration of gas, water, and montmorillonite. The study revealed changes in the water distribution and pore structure, which may relate to hydrate formation and clay concentration. At low clay concentrations (0.1 and 0.5 wt %), water molecules in pores dispersed, but at the 1 wt % group, blocking diminished, resembling the control group. The findings revealed the montmorillonite’s role in carbon dioxide hydrate kinetics within porous media, providing light on carbon dioxide sequestration in saline aquifers.