Numerical Simulation Method for Multi-Mechanism Flow in Tight Oil Reservoirs Based on Embedded Discrete Fracture Method

The diversity of fracture network patterns and reservoir characteristics, as well as the complexity of fluid occurrence and flow patterns in tight oil reservoirs, renders conventional numerical simulation methods insufficient. This study establishes a numerical simulation model for multi-mechanism flow within hydraulic fracture networks in tight oil reservoirs by considering rock compressibility, nonlinear fluid seepage, and imbibition processes. The semi-conductivity between the matrix and artificial fractures is coupled, and the automatic differentiation method is employed for solution. The reliability of the model is validated through history matching and production performance prediction of production data from a hydraulic fractured horizontal well in an actual tight oil reservoir. Practical application results show that the established model can successfully simulate tight oil reservoirs with large-scale complex fracture networks. Parameter sensitivity analysis indicates that nonlinear flow and stress sensitivity have negative impacts on production, while relative permeability hysteresis and capillary pressure curves exhibit positive effects. Among these, relative permeability hysteresis and stress sensitivity have relatively greater influences on productivity, and the special mechanisms of tight oil primarily affect production dynamics in the later stage. Therefore, this method effectively simulates the imbibition and displacement between the matrix and hydraulic fractures based on the coupling of hydraulic fracture and reservoir characteristics, providing theoretical insights for improving tight oil development performance.