Abstract The discrete fracture model (DFM) has been widely used to describe the flow problems in fractured media. In low-permeability media with conductive fractures embedded in, there is large capillary pressure contrast between fracture and matrix. It may cause very sharp changes of physical quantities near the matrix-fracture interface, which makes it difficult to calculate the matrix-fracture transfer flux accurately in the traditional DFM. In this article, mathematical analysis for the flow characteristics near the matrix-fracture interface is present. Three flow patterns can be distinguished for the two-phase steady flow across the matrix-fracture interface under the assumption of negligible capillary pressure in fracture. The analytical solutions for the three different patterns are derived and then employed to construct an alternative numerical scheme of calculating matrix-fracture transfer flow rate. Numerical examples show that the calculated results of the proposed model are in agreement with the reference solution. It indicates that the proposed model can overcome the difficulty of accurately predicting the matrix-fracture transfer flux in the traditional numerical scheme and then dramatically improve the computational accuracy for the two-phase flow in low-permeability reservoirs with conductive fractures.

中文翻译：

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涉及裂缝多孔介质毛细管压力不连续性的两相流离散裂缝模型

摘要 离散裂缝模型(DFM)已被广泛用于描述裂缝介质中的流动问题。在嵌入导电裂缝的低渗透介质中，裂缝与基质之间存在较大的毛细管压力差。这可能会导致基质-裂缝界面附近的物理量发生非常剧烈的变化，这使得传统DFM难以准确计算基质-裂缝转移通量。在本文中，对基质-裂缝界面附近的流动特性进行了数学分析。在假定裂缝中毛细管压力可忽略不计的情况下，可以区分穿过基质-裂缝界面的两相稳定流的三种流动模式。推导出三种不同模式的解析解，然后用于构建计算基质-裂缝传输流量的替代数值方案。数值算例表明，所提出模型的计算结果与参考解是一致的。表明该模型可以克服传统数值方案中基质-裂缝传递通量难以准确预测的问题，显着提高了含导流裂缝低渗透油藏两相流的计算精度。