Flow in fractured porous media is important in the community of geotechnics and geotechnical engineering. The matrix and fractures provide the pathways for fluid flow in fractured porous media. However, the difference in the permeability of matrix and fractures induces flow transfer between matrix and fractures. In this study, a generalized matrix-fracture flow transfer model for fractured porous media was proposed. The matrix-fracture flow transfer term depends on the effective pressure difference between matrix and fractures, which is expressed by the matrix pressure minus the product of the fracture pressure and the fracture pressure correction coefficient. The fracture pressure correction coefficient considers the influence of inconsistent fracture pressure around the matrix and variable flow transfer direction. Under specific conditions, this generalized transfer model was simplified to the matrix-fracture flow transfer model with shape factors. The influence of fracture occurrence and fracture-matrix permeability ratio on matrix-fracture flow transfer term was analyzed by numerical simulation. The shape factors and fracture pressure correction coefficients in different fractured porous media were compared. The results show that the matrix-fracture flow transfer term increases with the fracture trace length, density, and matrix-fracture permeability ratio, and the shape factor could not correctly reflect the change of fracture occurrence and fracture-matrix permeability ratio. The results also show the fracture pressure correction coefficient decreases as the fracture trace length, density, and matrix-fracture permeability ratio increase.

中文翻译：

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裂隙多孔介质的广义基体-裂隙流传输模型

破裂的多孔介质中的流动在岩土工程和岩土工程领域很重要。基质和裂缝为裂缝多孔介质中的流体流动提供了通道。然而，基质和裂缝的渗透率的差异引起基质和裂缝之间的流动转移。在这项研究中，提出了一种适用于压裂多孔介质的广义基体-裂隙流动传递模型。基体-裂缝流动传递项取决于基体与裂缝之间的有效压力差，其由基体压力减去裂缝压力与裂缝压力校正系数的乘积表示。断裂压力校正系数考虑了基质周围断裂压力不一致和流动传递方向可变的影响。在特定条件下，这个广义的传递模型被简化为具有形状因子的基质-裂缝流动模型。通过数值模拟分析了裂缝的发生，裂缝与基质的渗透率之比对基质-裂缝流动传递项的影响。比较了不同压裂多孔介质的形状因子和压裂校正系数。结果表明，随着裂缝痕迹长度，密度和基质裂缝渗透率的增加，基体裂缝流动传递项增加，形状因子不能正确反映裂缝发生和裂缝与基质渗透率的变化。结果还表明，随着裂缝迹线长度，密度和基质裂缝渗透率的增加，裂缝压力校正系数减小。