High heterogeneity and nonuniformly distributed multiscale pore systems are two characteristics of the unconventional reservoirs, which lead to very complex transport mechanisms. Limited by inadequate computational capability and imaging field of view, flow simulation cannot be directly performed on complex pore structures. The traditional methods usually coarsen the grid to reduce the computational load but will lead to the missing microstructure information and inaccurate simulation results. To develop a better understanding of flow properties in unconventional reservoirs, this study proposed a new upscaling method integrated gray lattice Boltzmann method (GLBM) and pore network model (PNM), accounting for the fluid flow in heterogeneous porous media. This method can reasonably reduce the computational loads while preserving certain micropore characteristics. Verifications are conducted by comparing the simulation and experimental results on tight sandstones, and good agreements are achieved. The proposed method is proven to be capable of estimating bulk properties in highly heterogenous unconventional reservoirs. This method could contribute to the development of multiscale pore structure characterizations and enhance the understandings of fluid flow mechanisms in unconventional reservoirs.

中文翻译：

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高度非均质非常规油藏流体流动模拟的一种新的升级方法

高度非均质性和非均匀分布的多尺度孔隙系统是非常规储层的两个特征，导致非常复杂的输运机制。由于计算能力和成像视场不足，无法直接对复杂的孔隙结构进行流动模拟。传统方法通常会粗化网格以减少计算量，但会导致微观结构信息缺失和模拟结果不准确。为了更好地了解非常规储层的流动特性，本研究提出了一种新的放大方法，结合灰色格子玻尔兹曼方法 (GLBM) 和孔隙网络模型 (PNM)，考虑了非均质多孔介质中的流体流动。该方法可以在保留一定微孔特性的同时，合理降低计算量。通过对比致密砂岩的模拟和实验结果进行了验证，取得了良好的一致性。所提出的方法被证明能够估计高度非均质的非常规储层的整体特性。该方法有助于发展多尺度孔隙结构表征，增强对非常规储层流体流动机制的理解。