Abstract In this paper, we consider fractured sorbing media (e.g., gas shale and coal bed methane reservoirs) as either dual porosity media comprising matrix-fracture or as triple porosity media comprising separate organic and inorganic matrix components and fractures. We accommodate the combination of mechanical deformation and desorption induced matrix shrinking in conditioning the evolution of fracture aperture and effective stress difference between each medium. These considerations result in an improved permeability evolution model (IPEM) for both dual porosity and triple porosity fractured sorbing media. Then we have simplified the model for triple porosity fractured sorbing media by reducing the geometry configuration from three dimensional to one dimensional, marked as SIPEM1. Specifically, SIPEM1 is a model simplified from the IPEM, and consider that when the size of the REV and the volumetric strain is small, replacing the volume with the side length of each layer medium in defining the model will bring relatively small error. This model is further simplified to SIPEM1-1 by assuming that the effective stress of each medium is the same. Then we have validated the models with field data. Finally, we compared prediction results from these models under different conditions. This study has found that IPEM is the most accurate model, especially for fractured sorbing media with a larger compressibility. SIPEM1-1 does not consider the difference of the effective stress of each medium and thus it is relatively less accurate in describing the evolution of permeability compared with SIPEM1 that considers this difference. This gap increases with the increase of permeability difference between fracture and matrix.

中文翻译：

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改进的渗透率演化模型及其在裂缝性吸油介质中的应用

摘要 在本文中，我们将裂缝吸附介质（例如，气页岩和煤层气储层）视为包含基质-裂缝的双孔隙度介质或包含单独的有机和无机基质成分和裂缝的三重孔隙度介质。我们适应机械变形和解吸引起的基质收缩的组合，以调节裂缝孔径的演变和每种介质之间的有效应力差异。这些考虑导致了双孔隙度和三孔隙度裂缝吸附介质的改进渗透率演化模型 (IPEM)。然后，我们通过将几何配置从三维减少到一维，简化了三孔裂缝吸附介质的模型，标记为 SIPEM1。具体来说，SIPEM1 是从 IPEM 简化的模型，并考虑到当REV和体积应变的大小较小时，定义模型时用每层介质的边长代替体积会带来相对较小的误差。通过假设每种介质的有效应力相同，将该模型进一步简化为 SIPEM1-1。然后我们用现场数据验证了模型。最后，我们比较了这些模型在不同条件下的预测结果。本研究发现，IPEM 是最准确的模型，特别是对于压缩性较大的裂隙吸附介质。SIPEM1-1 没有考虑每种介质有效应力的差异，因此与考虑这种差异的 SIPEM1 相比，它在描述渗透率演化方面的准确度相对较低。