Simulation of the natural fractures influence on hydraulic fractures propagation using high aspect ratio interface elements

Abstract

Hydraulic fracturing is a technique widely used in the oil and gas industry to improve production in low-permeability reservoirs by propagating fractures in porous media. However, the presence of natural fractures (NF) can significantly affect hydraulic fracture (HF) behavior. This work presents a numerical study via the finite element method and based on the use of high aspect ratio interface elements (HAR-IE), which are inserted into the mesh via the Mesh Fragmentation Technique, to reproduce several effects related to the interaction between HF and NF in deformable porous media. In this respect, the fluid flow in the porous media is governed by Darcy's Law, while the classical cubic law is applied to the fractures. The HF formation and propagation are based on a suitable tensile damage model. Moreover, this hydro-mechanical problem is solved in a fully coupled manner. The analyses satisfactorily demonstrate how the NF aperture and approaching angle influence the propagation of the HF. The simulations showed that the in situ stress state also has an important role in this kind of interaction. From these studies, HAR-IEs adequately reproduced different interactions between HF and NF and a diagram is proposed to relate all the complex interactions found.