改造双重介质模型的非侵入式嵌入式离散裂缝渗流模拟方法

A Non-intrusive Embedded Discrete Fracture Flow Simulation Method by Modifying Dual-Porosity Model

  • 摘要: 针对现有非侵入式嵌入式离散裂缝模拟(EDFM)方法因添加非相邻连接(NNC)易造成复杂网格拓扑混乱、破坏模拟器原生数据结构的问题。本文提出一种无需添加NNC而直接改造双重介质模型的非侵入式EDFM模拟方法,该方法可以构建一个与EDFM模型网格孔隙体积、网格间传导率、井指数均相同的等效双重介质模型,从而可以直接在商业模拟器中实现等效的EDFM模拟计算。本文以不混溶两相流为例,通过不同裂缝分布(直缝、交叉缝、复杂缝网)和不同开发方式(衰竭开发、注水开发)的多个算例验证,论证了该方法与EDFM在产油速度、含水率、压力和含油饱和度分布等计算结果高度匹配,平均计算误差低于0.3%。因此,该方法兼具EDFM对复杂裂缝网络的刻画精度与双重介质模型的工程实用性,为裂缝性油藏高效数值模拟提供了新途径。

     

    Abstract: To address the issue that existing non-intrusive Embedded Discrete Fracture Model (EDFM) methods tend to cause complex grid topology disorder and damage the native data structure of reservoir simulators due to the introduction of non-neighboring connections (NNCs), this paper proposes a non-intrusive EDFM simulation approach that directly modifies the dual-porosity model without adding NNCs. The proposed method can construct an equivalent dual-porosity model with the same grid pore volume, inter-grid transmissibility, and well index as the EDFM model, thereby enabling equivalent EDFM computations directly within commercial reservoir simulators. Taking immiscible two-phase flow as an example, the method is verified through multiple cases with different fracture distributions (linear fractures, intersecting fractures, complex fracture networks) and development modes (depletion development, waterflooding development). Numerical results demonstrate that the proposed method is highly consistent with the standard EDFM in terms of oil production rate, water cut, pressure, and oil saturation distribution, with an average computational error below 0.3%. Therefore, the proposed approach combines the high-precision characterization capability of EDFM for complex fracture networks and the engineering practicability of the dual-porosity model, providing a new route for efficient numerical simulation of fractured oil reservoirs.

     

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