Numerical modeling of hydraulic fracture propagation and reorientation

Hydraulic fracture propagation, the prevailing method of reservoir stimulation, is controlled by the in situ reservoir stress state. This controls hydraulic fracture orientation and, for the most part, the created hydraulic fracture geometry. In this study, the boundary element method based on the displacement discontinuity formulation is presented to solve general problems of hydraulic fracturing propagation under biaxial loading. The crack tip element and a higher order displacement discontinuity method are used to study the hydraulic fracture propagation and reorientation. The maximum tangential stress criterion (or sigma-criterion) is used to find the fracture path. The effect of fluid pressure and stress difference on the hydraulic fracture propagation is studied too. The developed numerical program (2DFPM) for modelling the reorientation process is verified by comparing its result with those of analytical and experimental tests, where a good agreement was observed. The numerical analysis showed that hydraulic fracture reorientation is effected remarkably by stress difference, fluid pressure and hydraulic fracture inclination.