The Energy Balance of a Hydraulic Fracture at Depth

TL;DR

This paper analyzes the energy balance of hydraulic fractures using a combined model, explaining different growth regimes and transitions through physical energy considerations, supported by numerical examples and industrial context.

Contribution

It introduces an energy-based framework to understand hydraulic fracture growth regimes and transitions, integrating lubrication flow and fracture mechanics.

Findings

Different propagation regimes are linked to dominant energy terms.

Transitions such as viscosity to toughness dominance are explained physically.

Numerical examples illustrate the evolution of energy contributions.

Abstract

We detail the energy balance of a propagating hydraulic fracture. Using the linear hydraulic fracture model which combines lubrication flow and linear elastic fracture mechanics, we demonstrate how different propagation regimes are related to the dominance of a given term of the power balance of a growing hydraulic fracture. Taking an energy point of view allows us to offer a physical explanation of hydraulic fracture growth behaviours, such as, for example, the transition from viscosity to toughness dominated growth for a radial geometry, fracture propagation after the end of the injection or transition to self-buoyant elongated growth. We quantify the evolution of the different power terms for a series of numerical examples. We also discuss the order of magnitudes of the different terms for a industrial-like hydraulic fracturing treatment accounting for the additional dissipation in the injection line.