Two evaluating parameters, R-squared and MSE, are shown in Table . The errors of responses are presented in Figure . The results show that the regressions are reliable because of low and independent errors. The analysis of variances was carried out through RSM. In the analysis of variances, the sum of the squared deviation of each parameter and error is calculated first, followed by the degree of freedom, mean square, F-value, and P-value. All of the parameters are significant because the parameter itself or its interaction with the other parameters has a suitable high F-value and low P-value. The amount of F-value and P-value are tabulated in Table . DOF represents the degree of freedom. The most decisive parameter for water saturation and resistance are porosity and pressure. Interaction between parameters is of significance for water saturation in some interactions. If the interactions are illustrated by the signs of parameters, the decisive interactions include ε -P, ε -T, ε -Sa, ε -Sc, Sc -Sa, Sa -P, and P -T. The most significant interaction is P -T.