Abstract Understanding and predicting gas transport in gas-shale reservoirs matrix containing abundant nanopores have tremendous implications for the development of gas-shale reservoir. However, there are many literature focusing on establishing gas transport models in a single nanopore, which is too ideal for the heterogeneous nanoporous shale. Besides, the water film and capillary water that existed on the inorganic pore and its effect on gas transport capacity are usually overlooked. In this work, based on the SEM (scanning electron microscope) images, the nanopores in OM (organic matter) are assumed as circular cross section shape, while that in inorganic are slit-like shape. The Beskok's model are employed to quantify the bulk-gas transport, and the additional flux contribution by surface diffusion in organic pore are also imbedded. The apparent gas permeability (AGP) model in a single nanopore is upscaled to sample scale with Monte Carlo sampling method, which successfully represents the heterogeneities of shale matrix including pore size distribution, total organic carbon (TOC) content, and water distribution. The proposed model fully takes into account the gas transport mechanisms, the complex flow boundary and the significant heterogeneity of the nanoporous shale. The reliability of the present model is successfully verified with the experimental data from different literature. Results show that Knudsen diffusion and surface diffusion are the two key transport mechanisms dramatically enhancing the AGP of shale matrix when the pressure is less than 6 MPa. The AGP of shale matrix containing abundant organic micropores (

中文翻译：

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纳米多孔页岩表观气体渗透率离散模型耦合初始水分布

摘要 理解和预测含有丰富纳米孔隙的气-页岩储层基质中的气体输运对气-页岩储层的开发具有重要意义。然而，有许多文献侧重于在单个纳米孔中建立气体输运模型，这对于非均质纳米多孔页岩来说过于理想。此外，存在于无机孔隙上的水膜和毛细管水及其对输气能力的影响往往被忽视。在这项工作中，基于 SEM（扫描电子显微镜）图像，OM（有机物）中的纳米孔被假定为圆形截面形状，而无机中的纳米孔为狭缝状。Beskok 模型被用来量化大体积气体传输，并且还嵌入了有机孔隙中表面扩散的额外通量贡献。使用蒙特卡罗采样方法将单个纳米孔中的表观气体渗透率 (AGP) 模型放大到样本规模，成功地表示了页岩基质的非均质性，包括孔径分布、总有机碳 (TOC) 含量和水分分布。所提出的模型充分考虑了纳米多孔页岩的气体输运机制、复杂的流动边界和显着的非均质性。不同文献的实验数据成功验证了本模型的可靠性。结果表明，当压力小于 6 MPa 时，Knudsen 扩散和表面扩散是显着提高页岩基质 AGP 的两种关键输运机制。含有丰富有机微孔的页岩基质的 AGP (