A numerical hybrid model for non-planar hydraulic fracture propagation in ductile formations.

In this paper, a hydro-mechanical model for non-planar hydraulic fracture propagation in ductile formations is developed based on the Drucker-Prager plasticity theory, Biot's theory and cohesive zone model (CZM). A hybrid extended finite element method (XFEM)-finite volume method (FVM)-embedded discrete fracture model (EDFM) method is proposed for numerical implementation. The XFEM and return-mapping method are used to simulate the deformation of inelastic media with strong discontinuities. The discontinuous pressure field is modelled by the EDFM and FVM. In addition, a dual-layer iterative algorithm is proposed to solve the strong nonlinear systems by a combination of the fixed-stress iteration, Picard iteration and Newton-Raphson iterative method. Then, the accuracy and ability of the proposed model are demonstrated through several reference cases. Finally, the proposed model are applied to two numerical cases and the influences of the plastic deformation on the simultaneous propagation of multi-fractures are investigated. • A poro-elasto-plastic model for non-planar hydraulic fracture propagation in ductile formations was developed. • A hybrid XFEM-FVM-EDFM method was proposed to conduct numerical implementation. • A dual-layer iterative algorithm was constructed to solve the strong nonlinear equation systems. • The effects of rock plasticity on multi-fractures propagation in the ductile formations were investigated. [ABSTRACT FROM AUTHOR]