Pore-Scale Characterization and Mass-Transfer Mechanism of Crystal Hydrate Gowth by Using 2.5D Microchip Observation

Underlying the micromechanism of hydrate phase change is significant for marine natural gas hydrate resources exploitation; however, current nondestructive microtesting techniques still suffer from issues of multiphase distinguish or continuous monitoring. Therefore, in this study, a direct real-time visualization method within a 2.5D microchip was first proposed and applied in gas hydrate research. Two different growth modes of methane (CH4) and methane-tetrahydrofuran (CH4-THF) hydrate after nucleation are found, and their respective control mechanisms are elucidated: the dominant factor for the different growth modes of (CH4) hydrate is the gas–water saturation in the pore. Meanwhile, the process of gas–water flow in the pore controls the growth of the (CH4-THF) hydrate. In addition, the intense propagation of (CH4-THF) hydrate film growth was found, and it was demonstrated that the propagation rate was negatively affected by liquid saturation. We provide theoretical basis and solution ideas for the scientific problems in the process of safe and efficient extraction of natural gas hydrate.