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将特征正交分解(POD)方法引入到页岩气流动双孔双渗模型的数值计算,建立了 POD投影模型.在建模过程中发现将气体在基质和缝网中的流动控制方程分别进行POD投影的方式,虽然在数学上正确且满足基质或缝网的质量守恒,但会人为地在基质与缝网间附加一个质量传递投影项,无法保证整个流动系统的质量守恒,从而影响了 POD模型的健壮性和精度.针对此问题提出了满足基质-缝网总体质量守恒的POD建模方式,在保证高精度(平均相对偏差约 0.8％)和快速计算(计算速度提高720倍)的同时,大大提高了 POD模型的健壮性.“,”Proper orthogonal decomposition (POD) method is introduced into numerical computations of shale gas flows in dual-porosity dual-permeability porous media. A POD projection model has been established. Although POD projection of the equations for matrix and fracture separately is correct in math while the mass conservation of matrix or fracture can be satisfied, artificial projection term caused by the mass transfer from matrix to fracture appears so that the mass conservation for the whole system cannot be guaranteed. Thus, the precision and robustness of the POD model are weak. To solve this problem, we propose a new projection manner that can guarantee the whole mass conservation of the matrix-fracture system. Numerical results show that the POD model can ensure high precision (mean relative deviation as low as 0.8％) and fast computation (computational speed promoted 720 times) with strong robustness, after using the new projection manner.