A novel fluid-solid coupling method for fractured reservoirs: 3D DDM-EDFM integration with proppant mechanics

This paper proposes a novel numerical simulation approach for fluid–solid coupling in fractured reservoirs, incorporating the mechanical properties of proppants into the coupling framework. By integrating the Displacement Discontinuity Method (DDM) with a three-dimensional Embedded Discrete Fracture Model (3D EDFM), the proposed method enables coupled simulations of geomechanics and fluid flow. Unlike conventional approaches, this method considers the time-dependent evolution of fracture aperture and accurately captures the mechanical effects of proppants during fracture closure. A comprehensive analysis is conducted to investigate the impacts on fracture dynamics and fluid flow behavior. The model’s reliability is validated through comparisons with analytical solutions and the Extended Finite Element Method (XFEM). Results demonstrate that the time-dependent evolution of fracture apertures significantly influences fluid flow in fractured reservoirs. Specifically, during the production stage, fracture closure results in a sharp decline in oil production rates. Larger proppant-supported apertures effectively mitigate fracture closure, sustain high fracture conductivity, and prolong the production period. Additionally, low-porosity reservoirs are shown to be more sensitive to rock deformation, leading to substantial changes in flow parameters during production. Thus, incorporating fluid–solid coupling is crucial for accurate modeling in low-porosity reservoirs. This study provides valuable theoretical insights for the development of unconventional resources.