High-pressure mercury intrusion analysis of pore structure in typical lithofacies shale

In this paper, statistical research on the characterization of pore and fracture structures is systematically conducted on shale reservoirs in different blocks and under different lithofacies conditions. The impact of lithological characteristics on shale pore fracture structures is revealed, and the coupling mechanism of "high-pressure mercury injection, pore fracture structure, and lithofacies" is clarified. Results show that: (a). When the capillary force is equal to 0.0035 MPa, the pore throat radius is equal to 209.661 μm. (b). There exist turning pressures both in injection curve and removal curve. When the capillary pressure is lower than 100 MPa, the slope of injection curve is high, while when the capillary pressure is higher than 100 MPa, the slope of injection curve becomes lower. (c). The majority of pores is distributed in the pore size interval range from 0.063 μm to 0.004 μm. (d). There are also a certain amount of regular pores in inorganic pores. Part of the pores are secondary intergranular dissolved pores formed by later dissolution.