Hydrodynamic modeling of mud loss controlled by the coupling of discrete fracture and matrix

In drilling engineering, the knowledge and control of mud loss are significant. Previous models of mud-loss exhibit two deficiencies: (1) fracture networks were not considered and (2) the fluid flow between the fracture and the matrix was not considered. In these regards, this study adopted a Monte Carlo stochastic simulation method to construct a geological model of discrete fracture networks of naturally fractured reservoirs and then found leakage tunnels. The coupling of discrete fractures and matrix was considered to establish the mathematical model. Consideration of the mud compressibility and the yield-power-law of fluid rheology have produced a more general model compared with previous ones. The finite element method and finite difference method were selected to deduce the numerical format of the matrix and fracture. The laws of mud loss in naturally discrete fractured reservoirs can be mastered through numerical calculation based on MATLAB. A sensitivity analysis is conclusively performed to identify the most influential factors on mud loss. The current model, which is more realistic compared with previous models, was validated by application to practical projects.