A New Fully Projection-Based Embedded Discrete Fracture Model for Simulating Fluid Transient Flow

Abstract The embedded discrete fracture model (EDFM) has been widely adopted to simulate fractured reservoirs efficiently. Yet, its accuracy remains limited for transient flow dynamics, particularly in capturing early-time interactions between fractures and adjacent matrix regions. Existing projection-based EDFM (pEDFM) methods improve accuracy for low-conductivity fractures but exhibit asymmetric pressure distributions due to restricted geometric projections. To address these limitations, this work proposes a fully projection-based embedded discrete fracture model (FPEDFM) that projects fractures onto all six faces of host matrix cells, systematically incorporating the influence of surrounding matrix domains. By calculating projection weights through volumetric ratios and attenuating original transmissibility terms, FPEDFM ensures mass conservation while resolving asymmetric pressure artifacts. Numerical validation against an industry-standard software package demonstrates that FPEDFM achieves superior agreement with reference solutions, reducing mid-stage pressure derivative deviations observed in previous models. Symmetric pressure distributions near fractures are achieved, aligning with physical expectations for homogeneous reservoirs. The proposed model may provide an efficient and accurate framework for transient flow analysis in multi-stage fractured horizontal wells (MFHWs), offering enhanced predictive capabilities for reservoir performance and production optimization.