Experimental observation of formation and dissociation of methane hydrate in a micromodel

Abstract Understanding the mechanisms of hydrate formation and dissociation is significant for natural gas hydrate exploration. In this study, a porous micromodel was used to visualize the formation and dissociation of methane hydrate in methane-pure water and methane-brine systems via a microfluidic approach. Various methane hydrates with different growth characteristics were formed, which may result from variations in the sizes and distributions of methane bubbles. The differences in the mode of methane hydrate formation were associated with various phenomena during hydrate dissociation. The size, number and size distribution of the dissociated methane bubbles were quantitatively analyzed to describe hydrate dissociation behavior. Hydrate dissociation in the methane-brine system differed significantly from that in the methane-pure water system. Furthermore, multiple formation-dissociation processes of methane hydrate were investigated. The results indicated that multiple formation-dissociation processes can significantly impact the characteristics of the gas–liquid interfaces, which could influence the subsequent hydrate formation and dissociation behaviors.