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

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.