Pore Throat Division of Zhiluo Formation Sandstone in Binchang Mining Area Based on Mercury Injection Test

In order to study the size and proportion of the pore throats in Zhiluo formation sandstone in Binchang Mining Area, the size and distribution of different pore throats corresponding to mercury injection pressure were studied by means of mercury injection test, which were used to divide different pore throats intervals and quantitatively describe the percentage of pore throats to pore volume. The results show that the sandstone pore throats in Zhiluo formation are more developed, more in quantity and better in connectivity, but the vertical homogeneity is poor. The macro pore throats accounted for 0.69% of the pore volume, meso pore throats accounted for 34.43% of the pore volume, and pore throats and micro pore throats accounted for 38.68% and 24.91% of the pore volume, respectively. As the main seepage channel of sandstone aquifer, medium and small pore throat, which accounts for 73.11% of pore volume, largely determines the permeability of sandstone.