Hydraulic fracturing is a widely used technique to produce several conductive fractures in low-permeability reservoirs resulting in the improvement of production. The embedded discrete fracture model has received considerable attention to simulate the flow in fractured reservoirs due to its low cost. In low-permeability reservoirs with conductive fractures, there is a large capillary pressure difference between matrix and fracture. This difference may cause the pressure and saturation to change very sharply near matrix-fracture interfaces. However, it is difficult to calculate the matrix-fracture transfer flux accurately for the traditional embedded discrete fracture model. According to the recent research conclusion, three flow patterns can be distinguished for two-phase steady flow across the matrix-fracture interface. In this article, a modified embedded discrete fracture model is proposed, in which the one-dimensional analytical solution is employed to construct the numerical scheme of calculating the matrix-fracture transfer flow. Numerical tests show that the simulation results of the proposed embedded discrete fracture model are in agreement with the reference solution, in spite of the degree of the capillary pressure strength in the matrix. In contrast, the accuracy of the traditional embedded discrete fracture model depends on the degree of the capillary pressure strength in the matrix.

中文翻译：

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考虑毛细管压力差的高级嵌入式离散断裂模型

水力压裂是在低渗透油藏中产生数个导电裂缝的一种广泛使用的技术，从而提高了产量。嵌入式离散裂缝模型因其低成本而受到了广泛的关注，以模拟裂缝性油藏中的流动。在具有导电裂缝的低渗透油藏中，基质与裂缝之间存在较大的毛细管压力差。这种差异可能导致压力和饱和度在基体-断裂界面附近急剧变化。但是，对于传统的嵌入式离散裂缝模型，很难准确地计算出基质裂缝的通量。根据最近的研究结论，对于穿过基质-裂缝界面的两相稳定流，可以区分三种流型。在这篇文章中，提出了一种改进的嵌入式离散裂缝模型，该模型采用一维解析解构造了计算基质-裂缝传递流的数值方案。数值试验表明，所提出的嵌入式离散断裂模型的仿真结果与参考解相符，尽管基体中的毛细管压力强度不同。相反，传统的嵌入式离散裂缝模型的精度取决于基质中毛细管压力强度的程度。数值试验表明，所提出的嵌入式离散断裂模型的仿真结果与参考解相符，尽管基体中的毛细管压力强度不同。相反，传统的嵌入式离散裂缝模型的精度取决于基质中毛细管压力强度的程度。数值试验表明，所提出的嵌入式离散断裂模型的仿真结果与参考解相符，尽管基体中的毛细管压力强度不同。相比之下，传统的嵌入式离散断裂模型的精度取决于基质中毛细管压力强度的程度。