An approach to hydraulic fracture in geomaterials through a porous brittle damage material model

Gianluca Caramiello,Anna Pandolfi,Andrea Montanino,Gabriele Della Vecchia

doi:10.1186/s40323-018-0117-4

Gianluca Caramiello, Anna Pandolfi + Show 2 more

Open Access

https://doi.org/10.1186/s40323-018-0117-4

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Abstract

A coupled hydromechanical code based on a distributed brittle damage material model has been developed in order to simulate hydraulic fracturing processes. As specific feature, the code does not assume the development of a discrete number of sharp cracks but considers a diffused damage that takes place under overall confinement of the system. The code is validated against a laboratory test reproducing the local effects of a hydraulic fracturing procedure. The numerical model of the laboratory test is then used to conduct a parametric analysis where the influence of the principal hydromechanical parameters on the hydraulic fracturing performance is assessed. Finally, the code is applied to simulate multiple hydraulic fracturing interventions in a large scale shale reservoir. In all applications considered, the model shows a good predictive capability in terms of damage extension.

Highlights

Hydraulic fracturing is a process characterized by the nucleation and propagation of multiple diffused fractures in soil or rock masses as a consequence of a localized solicitation driven by hydraulic pressure
A coupled hydromechanical code based on a distributed brittle damage material model has been developed in order to simulate hydraulic fracturing processes
The code is validated against a laboratory test reproducing the local effects of a hydraulic fracturing procedure

Summary

Introduction

Hydraulic fracturing is a process characterized by the nucleation and propagation of multiple diffused fractures in soil or rock masses as a consequence of a localized solicitation driven by hydraulic pressure. Looking back at the literature in the topic, early attempts to model hydraulic fracturing were based on analytical solutions, obtained by assuming that a unique well-defined crack propagates within an elastic medium under the action of a pressure, disregarding the hydromechanical coupling and nonlinear effects. Such models are not able to account for the fluid flow within the reservoir, the damage processes around the stimulated area, and the fluid-solid interaction. The permeability of a rank-Q material can be estimated as the sum of the contributions of the single fault families, as kf

ΔjN 3 12 Lj

Conclusions