Investigation on Coupled Fluid-Flow and Stress in Dual Model Rock Mass with Time-Dependent Effect and Its Simulation

The coupled fluid-flow and stress model with time-dependent effect is developed. In this model, rock mass is simulated as a homogeneous and isotropic dual-porosity, dual-permeability continuum. Darcy’s law is used to describe the fluid flow in a porous medium, and cubic law is used to describe the flow in fractures. The finite element method is introduced to solve the system, and the effects of fractures and fracture spacing are considered numerically. The numerical results indicate that fractures have a significant impact on the rocks’ displacement and pore pressure. It also shows an increase in plastic strain with decreasing fracture spacing, as does the creep strain. The coupled process is highly sensitive to the fracture spacing. A series of numerical simulations are conducted to better understand the complex coupled processes, which leads to an improved understanding of different aspects of naturally fractured reservoirs and may impact on experimental design to explore these attributes in a real reservoir situation.