College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, China

With the integration of core physical property, mercury injection data and gas test data, the authors determined the lower limit value by empirical statistics, median pressure method, 0.1 μm mercury saturation method, pore throat radius method, porosity-permeability cross-po method, and used the method of gas testing for validation. It is concluded that porosity and permeability lower limit value were 3.558% and 0.008 5×10^-3 μm² for the intermediate-basic volcanic rocks of W studied area in southern Songliao Basin.