An explicitly coupled hydro‐geomechanical model for simulating hydraulic fracturing in arbitrary discrete fracture networks

TLDR

Modeling hydraulic fracturing in the presence of natural fracture networks is challenging due to complex fluid–rock–interface interactions and fracture propagation dynamics. The study aims to present an explicitly integrated, fully coupled discrete‑finite element approach for simulating hydraulic fracturing in arbitrary fracture networks. The method couples finite element geomechanics, finite volume hydrodynamics, a geomechanical joint model for interfaces, and adaptive remeshing into separate modules. The model reproduces the Khristianovich–Geertsma–DeKlerk solution for single‑fracture propagation, matches laboratory data on fracture–fracture interaction, and demonstrates preliminary simulations in multi‑fracture natural networks. © 2012 John Wiley & Sons, Ltd.

Abstract

SUMMARY Modeling hydraulic fracturing in the presence of a natural fracture network is a challenging task, owing to the complex interactions between fluid, rock matrix, and rock interfaces, as well as the interactions between propagating fractures and existing natural interfaces. Understanding these complex interactions through numerical modeling is critical to the design of optimum stimulation strategies. In this paper, we present an explicitly integrated, fully coupled discrete‐finite element approach for the simulation of hydraulic fracturing in arbitrary fracture networks. The individual physical processes involved in hydraulic fracturing are identified and addressed as separate modules: a finite element approach for geomechanics in the rock matrix, a finite volume approach for resolving hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive remeshing module. The model is verified against the Khristianovich–Geertsma–DeKlerk closed‐form solution for the propagation of a single hydraulic fracture and validated against laboratory testing results on the interaction between a propagating hydraulic fracture and an existing fracture. Preliminary results of simulating hydraulic fracturing in a natural fracture system consisting of multiple fractures are also presented. Copyright © 2012 John Wiley & Sons, Ltd.