Research of ABAQUS numerical simulation of 3D fracturepropagation in hydraulic fracturing process

The hydraulic fracturing treatment in oil well is a process of solid-fluid coupling in porous medium. In this paper, continuity equation of hydraulic fracturing fluid seepage and stress equilibrium equation of rock deformation are established, the criterion for fracture initiation of quadratic nominal stress and fracture propagation of critical energy release rate is introduced, horizontal flow and vertical flow of fluid along fracture is considered, and the Soil module in finite element tool ABAQUS is applied to stimulate 3D composite fracture initiation and propagation in hydraulic fracturing. The cohesive element is used to pre-define the fracture path, and the corresponding user subroutines are also developed and embedded into ABAQUS to determine the initial in-situ stress field ,seepage field, depth-dependent porosity and time-related loss coefficient. The result of numerical simulation can show fracture geometry, fluid pressure distribution along fracture, rock deformation and stress distribution, pore pressure distribution and fluid loss at different time points of pumping in hydraulic fracturing. Apart from that, the influence of fluid properties, volume, interlayer stress difference and loss coefficient on fracture geometry is analyzed.