An experimental investigation of matrix components and grain size influence on the permeability in porous medium containing hydrate

Natural gas hydrate is a kind of potential alternative energy, widely distributed in deep water deposits. Permeability is one of the most important factors during this underground energy extraction, determining production efficiency and economic benefits. Based on special characteristics of natural gas hydrate, a set of experimental apparatus is designed to study the influence of matrix components and grain size on permeability in porous medium with different hydrate saturation. The results suggest that the permeability of porous medium containing hydrate is significantly smaller than that of conventional sample. Under the same hydrate saturation, larger grain size can always improve the sample permeability. According to the curves' shape of the permeability variations over time, grain size effect should be divided into two grades by particle size. Moreover, the existence of clay can greatly weaken the permeability of sand sample. Generally, the sample permeability decreases with the increase of clay content. When the matrix content is dominated by clay, the weakening effect is greatly reduced. At last, a modified empirical relation formula is fitted by related experimental data on the basis of Masuda model.