Clay Particle Migration and Associated Permeability Damage in Natural Gas Hydrate-Bearing Clayey-Silty Sediments: A Review

Natural gas hydrate (NGH) is a highly promising alternative energy source for the future, which is widely distributed in marine clayey-silty sediments. Permeability is the key factor determining the efficiency of NGH exploitation. However, clay particles can migrate and clog the pores, leading to a decrease in reservoir permeability during the development of NGH. This review summarizes the permeability damage law during the NGH production from clayey-silty sediments, with a focus on the influence of clay particle migration. For the scientific problem of clay particle migration, the governing equation of clay particle migration was first clarified through force balance analysis. Then, the influencing factors and laws of clay particle migration were systematically summarized from two aspects: internal factors such as clay type, content, particle size, reservoir heterogeneity, and external conditions such as salinity, flow rate, temperature, pH, and stress field. The detachment, migration, aggregation and clogging characteristics of clay particles in porous media were observed and outlined based on microscopic visualization technology. Thirdly, the numerical simulation methods of particle migration were summarized, and the permeability damage laws and its influence mechanism were analyzed. Finally, the limitations on clay particle migration and permeability damage in the current research were discussed, and corresponding suggestions were given to promote the efficient development of NGH.