Table 1: The data of rate-controlled mercury injection (RMICP) and nuclear magnetic resonance (NMR) experiments and the corresponding helium porosity and air permeability of the samples from the Upper Triassic Chang 7 Member, Odors Basin.

SamplesTotal mercury saturation (%)Pore mercury saturation (%)Throat mercury saturation (%)Valid Throat volume in per unit of rock (mL/cm3)Threshold pressure (psi)Threshold (maximum) throat radium (μm)Average pore radius (μm)Average throat radius (μm)Average pore/throat ratioStandard deviation coefficient of throat radiiMovable water saturation (%)Valid porosity for movable water (%)Irresistible water saturation (%)Helium porosity (%)Air permeability (×10−3μm2)ε

z-147.1732.1215.040.015228.700.48164.320.34550.220.2334.933.4465.079.850.01024.36
z-246.7031.0715.630.016274.080.40162.460.29657.510.2530.033.0969.9710.280.00684.80
z-359.8944.0715.820.017159.020.69162.740.42492.900.2956.056.1443.9510.950.3837.29
z-451.8436.8814.960.017257.050.42163.090.29661.210.2635.534.0064.4711.250.01345.76
z-552.9340.0112.920.015258.080.42166.380.28691.160.2637.404.2262.6011.290.0146.02
z-656.8540.6916.160.019191.840.57159.810.35559.510.2847.385.4252.6211.450.0186.96
z-749.0029.6219.380.015203.060.54163.400.27522.290.35///7.580.1064.83
z-835.9618.4817.480.026292.230.37153.800.28602.900.22///14.770.0125.55
z-944.9432.5012.440.019280.550.39163.600.26764.210.28///14.950.0168.56
z-1037.6120.9416.670.017167.230.65159.360.47418.750.32///10.310.1395.89
z-1132.9013.4319.470.012203.310.54162.290.32405.120.25///6.320.0412.43

Standard deviation coefficient, which was used to characterize the mathematic distribution of throat radius, was employed in this paper. The equation is as follows: , in which б is the standard deviation coefficient; is mathematic standard variation of throat radius; is the throat radius; is the average of throat radius; and is the proportion of corresponding throat radius. The combination parameter of pore-throat structure (ε) was calculated by the equation: , in which Ф is helium porosity; α is pore/throat ratio; is the percolation threshold (maximum) throat radius; б is standard deviation coefficient of throat radius. The physical meaning of ε is length (μm).