Influence of the Particle Size of Porous Media on the Formation of Natural Gas Hydrate: A Review

摘要

As a new source of energy with great potential, natural gas hydrate (NGH) will play an indispensable and important strategic role in the future because of its tremendous reserves and wide application prospects in industry. It is of great significance to study the factors affecting the formation and occurrence of NGH for its exploration and exploitation under natural conditions and its application in industry. Since the sediments where NGH are mostly found are in porous media, the impact of porous media on the formation and occurrence of NGH has always been a research focus. This review focuses on the effects of the particle size of porous media on hydrate nucleation, growth, the conversion of water to hydrate, and phase equilibrium by summarizing previous studies. And occurrence characteristics of hydrates in porous media and the application of hydrate-based technologies are reviewed. A thorough analysis of the existing literature suggests that there is no consistent conclusion on the influence of the particle size and surface characteristics of porous media on hydrate formation. There is some debate, and the existence of a critical size of porous media needs further exploration. In addition, the interaction mechanism between the complex pore structure of porous media and the joint effects of particle size and initial water saturation on the hydrate formation process is still not clear. Thus, the influence of different initial water saturation conditions and pore structures on the formation and occurrence of NGH under different particle size conditions should be studied in the future to provide a reference for understanding the mineralization mechanism of NGH under natural conditions. Finally, some suggestions are put forward for studies of gas hydrate formation.