Fractal Characteristics of the Pore Structure of Low Permeability Sandstone

Based on the laboratory testing of mercury injection with natural cores of low permeability, such analyses were made as the changing law of capillary pressure curves, the distribution features of different size pores and the correlation of pore structures to inside fluid distribution. The fractal method was also used to analyze the two-section line fitting effect of the fractal dimensions and their relationship with the pore distribution laws. The results show that the low permeability reservoir has complicated pore system with high scale of fractal pores, of which the log-log correlation of SHg similar to Pc can be fitted well with two-section lines, and the two-sections fractal dimensions calculated have greater difference than that of medium & high permeability reservoirs. The study indicates advantages of the fractal method to describe the heterogeneous pore distribution of the low permeability sandstones.