## 4 Discussions  
### The Effect of the Characterization Parameters on Reservoir Properties  
Combining Matlab and the high-pressure mercury injection to quantitatively analyze the pore throat parameters of tight sandstone, the main parameters are simultaneous with the porosity and permeability of the samples. In order to reduce the interaction factors of porosity and permeability, permeability is controlled between 0.35 and 0.55 (based on an average permeability of 0.452), to explore the relationship between average pore throat radius, skewness, sorting coefficient, median pore throat radius, median pressure, average pore throat coordination number, average pore radius, pore throat ratio, and porosity. The results are shown in Table 2. Likewise, we also control the porosity between 6.5-8.5% (based on the average porosity of 7.728%), and explore the average pore throat radius, skewness, sorting coefficient, median pore throat radius, median pressure, coordination number, average pore radius, pore throat ratio, and permeability. The results are also shown in Table 2.  
As shown in Table 2, the average pore throat radius, sorting coefficient, median pore throat radius, coordination number, and pore throat ratio of the tight sandstone all have a large impact on permeability (Figure 9). Among these parameters, the permeability of tight sandstone has a positive correlation with the sorting coefficient and the average pore throat radius; the correlation coefficient between them is high. On the contrary, the permeability decreases with the increasing ratio of pore and pore throat, but the linear relationship is lower. Based on the high-pressure mercury injection curve, the porosity is negatively correlated with the median pore throat radius. The median pore throat radius of the study area is mainly affected by the intergranular pore, which was composed of the main reservoir space. The larger the median pore throat, the smaller the throat. When the throat that composed the main reservoir space becomes small, the porosity also decreases. For porosity, it is mainly influenced by the average pore radius, the median pore throat radius, and the coordination number of the tight sandstone, and it is positively correlated with the average pore radius and the average pore throat coordination number, and it is negatively correlated with the median pore throat radius with R\({}^{2}\) (0.5). Since the sorting coefficient represents the heterogeneity of pore distribution, the pore throat ratio and average pore throat coordination number represent the development degree of the number of throats, so the permeability is mainly controlled by the pore throat in the tight sandstone. The larger pore-throat radius, the higher the permeability of tight sandstone. For porosity,  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Characteristic Parameter of Pore-Throat** & **Permeability** & **Porosity** \\ \hline Average Pore Throat Radius/\(\upmu\)m & +0.693 & \(-\)0.080 \\ Skewness & +0.014 & \(-\)0.001 \\ Sorting Coefficient & +0.702 & \(-\)0.005 \\ Median Pore Throat Radius/\(\upmu\)m & +0.445 & +0.264 \\ Median Pressure (MPa) & +0.169 & +0.145 \\ Average Pore Throat Coordination Number & +0.856 & +0.217 \\ Average Pore Radius/\(\upmu\)m & +0.021 & +0.375 \\ Pore Throat Ratio & \(-\)0.448 & \(-\)0.007 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Relation coefficient between different parameters of pore throat and porosity and permeability.  
because the linear correlation coefficient of each parameter is less than 0.5, the correlation with the pore throat parameters is poor.