Numerical investigation of hydraulic fracture height growth in layered rock based on peridynamics

Abstract

In this study, we explore hydraulic fracture (HF) propagation and fracture height growth in layered rocks using a self-developed three-dimensional hydraulic fracturing model based on peridynamics. The influences of the rock dip angle, rock interface strength and in-situ stress distribution on the HF propagation in the height direction and the fracture distribution are studied. In horizontally layered rock formations, the in-situ stress distribution significantly affects the HF propagation pattern. The HF preferentially propagates into the rock layer with lower horizontal stress. In inclined layered rock formations, the interaction between the HF and the interfaces controls fracture propagation in the height direction. A smaller layer dip angle and larger vertical stress enables the HF to penetrate the interface and propagate in the height direction. A larger layer dip angle and lower interface strength (toughness) causes the HF to be more easily captured by the interfaces and further promotes fracture propagation in the height direction. Furthermore, we simulated fracture propagation in a thin-interbedded reservoir. The simulation results show that the fracture propagation pattern in the thin-interbedded reservoir is very complex due to the anisotropy of the formation, and the HFs in the thin-interbed are usually rough surfaces.