Cross Fracture Simulation Based on Cohesive Element

Abstract

Based on the theory of rock mechanics and fracture mechanics, the hydraulic crack and natural crack are set by Cohesive element, the finite element software ABAQUS is used to set up a two-dimensional model of cross-crack propagation, which is based on fluid-solid coupling. The target mesh is locally encrypted according to the crack fracturing and propagating position, and the near boundary uses a larger mesh density, which can control the calculation accuracy and reduce the calculation time. The model is used to analyze the influence of different stress difference and the angle between natural crack and maximum horizontal stress on the intersection of cracks. The results show that when the ground stress difference is small, the hydraulic crack will crack along the natural crack. When the stress difference is large, the hydraulic crack will extend along the direction of the maximum horizontal principal stress; when the angle between the natural crack and the maximum horizontal ground stress is small, the hydraulic crack extends along the direction of the natural crack. When the angle is large, the hydraulic crack directly penetrates the natural crack and extends along the direction of the maximum horizontal principal stress.