Micromechanics of wing crack propagation for different flaw properties

Duriez, J; Scholtès, Luc; Donzé, Frédéric

doi:10.1016/j.engfracmech.2015.12.034

Cited by 64 publications

(18 citation statements)

References 51 publications

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“…In particular, the discrete element method (DEM) was chosen because of its capability to simulate the propagation of fractures within a rock matrix containing preexisting heterogeneities such as bedding and varying kerogen concentration along laminations (Scholtès and Donzé, 2012). For instance, this method has already been used for the analysis of rock failure mechanisms involving wing crack propagation (Duriez et al, 2016), fractures coalescence (Scholtès and Donzé, 2012) or even hydrofracture propagation (Papachristos et al, 2016).…”

Section: Numerical Simulation Of Shale Maturationmentioning

confidence: 99%

Microfracturing during primary migration in shales

et al. 2017

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In several geological environments, chemical reactions are coupled to rock deformation and the associated stresses induced locally interact with the far field loading. This is the case in immature shales that undergo burial and diagenesis, where the organic matter evolves with temperature into hydrocarbons which induces local volume expansion. At large scale, this mechanism is responsible for the transport of hydrocarbons from source to reservoir rocks, a process referred to as primary migration. However, how the interactions between local fluid production, microfracturing, and transport are coupled remain to be understood. Here, we analyze this coupling phenomenon by developing a discrete element model where the generation of local overpressures occurring in kerogen patches is simulated, while the surrounding rock is subjected to external loading. It is shown that, due to local fluid overpressure; microfracturing occurs and brings the fluids to migrate through the medium. The numerical results are confirmed by laboratory experiments where the network of microfractures induced in an immature Green River shale sample heated under small differential stress was imaged in three dimensions using X-ray microtomography. Moreover, the numerical simulations identify that the state of differential stress and the initial kerogen distribution constitute two key parameters that control the formation of the three-dimensional percolating microfracture network and could thus explain primary migration in shale rocks.

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Section: Numerical Simulation Of Shale Maturationmentioning

confidence: 99%

Microfracturing during primary migration in shales

et al. 2017

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“…For this purpose, a two-dimensional discrete element model (DEM) [3] will be employed. The open source code Yade [4] has been chosen for the numerical computations since it has been extensively presented and validated in previous papers [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Failure in granular media from an energy viewpoint

Hadda

Sibille

Nicot³

et al. 2016

Granular Matter

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The present paper examines failure in discrete granular media with respect to its mode and nature based on energetic considerations through a comprehensive discrete element modelling computational analysis. The mode of failure refers to whether deformations will localize into an intense shear band or be diffuse. More subtly, a given failure mode can be effective with a burst of kinetic energy, or noneffective with a more controlled release of kinetic energy, depending on the control parameter. Physical quantities based on energy considerations with elementary decompositions of externally applied energy into elastic, plastic and kinetic contributions at the particle level are computed for a number of granular assemblies under a variety of failure scenarios. With the picture of a particle system experiencing macroscopic deformations according to underlying microand meso-mechanisms, it is concluded that computed grainenergy components depend on the microstructural detail that emerges as a function of loading program and control parameter. The relationship between elastic unloading outside a shear band and plastic dissipation inside it under both strain and stress control modes determines the genesis of shear banding in terms of plastic work dissipation minimization. Most interestingly, it is found that the energy signature inside the shear band in a dense granular packing is germane to This article is part of the Topical Collection on Micro origins for macro behavior of granular matter.B Nejib Hadda energy characteristics of diffuse failure in a loose assembly, suggesting some similarities in microscopic failure processes between shear banding and diffuse failure.

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“…Equation 8 representing the overall permeability includes three parts: (a) the term k 0 ij denoting the isotropic permeability of the intact rock, (b) the term k 0…”

Section: Mass Balance and Fluid Flowmentioning

confidence: 99%

“…In this approach, the local failure events occur in the form of breakage of the individual units or bonds, the propagation, and coalescence of which eventually lead to macroscopic failure (see, eg, other studies()). Among the discrete methods, the discrete element method (DEM) has particularly shown to be capable of capturing the complex fracture behavior of crystalline rocks (see, for instance, Duriez et al), where DEM and bonded spherical particles were used to investigate wing crack propagation in rocks with pre‐existing defects.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of fracturing in permeable rocks via a micromechanical continuum model

Eghbalian

Wan

Pouragha

et al. 2019

Num Anal Meth Geomechanics

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Summary The paper presents a micromechanical approach to describe the failure of low‐permeability brittle rocks as a multiscale fracturing process based on a poroelastic microcrack‐damage model. Failure is formulated deep down at the fine pore scale as a material degradation phenomenon driven by microcrack growth that also impacts upon hydromechanical properties. A set of damage tensors describes the effect of dual‐scale porosities (nanopores and microcracks) on both the hydraulic and poroelastic rock properties. Essentially, the multiscale model reconstructs the coupling effect of hydromechanical forces at the continuum level from the ground up through the upscaling of multiphase interactions at the fundamental structural level of the material. As a result, many macroscopic characteristics emerge naturally such as friction angle, fracture properties, and most importantly, Biot's coefficient taking on a tensorial form that is generally anisotropic. The model is validated within the framework of finite elements to illustrate various baseline constitutive features such as the effect of microcrack growth on the nonlinear stress‐strain response and the induced anisotropy in the context of lab experimental tests and boundary value problems. Heterogeneities of the rock samples were incorporated by choosing material properties to be stochastic following Weibull and lognormal distributions. Numerical results appropriately replicated typical experimental observations where fracture localization and propagation are shown to be a multiscale phenomenon emerging from microcrack growth and coalescence at the microscale, with concomitant enhancement in fluid conductivity.

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Micromechanics of wing crack propagation for different flaw properties

Cited by 64 publications

References 51 publications

Microfracturing during primary migration in shales

Microfracturing during primary migration in shales

Failure in granular media from an energy viewpoint

Numerical modeling of fracturing in permeable rocks via a micromechanical continuum model

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