Prediction of rock elastic moduli based on a micromechanical finite element model

Sun, Zhuang; Salazar-Tio, Rafael; Duranti, Luca; Crouse, Bernd; Fager, Andrew; Balasubramanian, Ganapathi

doi:10.1016/j.compgeo.2021.104149

Cited by 8 publications

(8 citation statements)

References 52 publications

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“…In order to setup a finite element (FE) micro-mechanics rock model from micro-CT data, two critical pre-processing steps are required: (1) grain-grain segmentation, and (2) conformal meshing of grain contacts. We have described these steps in detail in [23], but for the sake of completeness we include here a brief description.…”

Section: Methodsmentioning

confidence: 99%

“…A conformal mesh indicates that there is neither separation nor overclosure between any two grains of contact. The labeled voxelized 3D image is transformed into an unstructured mesh representation, where elements of the same grain are suitable for FE simulation and the elements at each side of a contact between grains conform to each other perfectly, without voids or overlaps in the contact boundary [23]. We generate the meshing for all the grains together, while maintaining the indices representing segmented grains, which results in a conformal mesh at the grain-grain contact.…”

Section: Methodsmentioning

confidence: 99%

“…Using this sphere pack model we demonstrate that the parametric cohesive contact model can mimic the free grain contacts. Following reference [2,23], we use a material property of quartz for the sphere packing: density is 2.65 g/cm 3 , bulk modulus is 37.0 GPa, and shear modulus is 44.0 GPa. Table 1 summarizes the specifications for the sphere pack model.…”

Section: Free Grain Contactsmentioning

confidence: 99%

“…We recently introduced a micromechanics digital rock workflow based on finite element modelling of grain structures obtained from micro-CT images [23]. Some unique features of this workflow include, a robust grain-grain segmentation method, a conformal grain-grain contact meshing algorithm, and grain relocation capabilities, instead of modelling a solid framework as a whole.…”

Section: Introductionmentioning

confidence: 99%

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Micromechanics Digital Rock: Parameterization of Consolidation Level using a Grain Contact Model

Sun

Salazar-Tio²,

Fager³

et al. 2023

E3S Web Conf.

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The mechanical behaviour of sedimentary rocks is conditioned by the interactions at the grain-grain contacts. We present a micromechanics digital rock workflow based on a cohesive contact model and introduce a general parameterization that can capture two extreme contact behaviours: free grains and fixed grains, as well as any intermediate degree of grain consolidation. With this parametric cohesive contact model, we can simulate a wide range of sedimentary rocks, from unconsolidated to well-consolidated rocks. We present a benchmark study on several samples and compare with laboratory-measured elastic moduli to calibrate its degree of consolidation. Simulations that do not include the grain contact modelling, tend to overestimate the elastic moduli, which manifests the significance of this contribution to capture well the grain contact behaviour. To demonstrate the impact of properly capturing the degree of consolidation on the rock strength and failure pattern, we present results for numerical uniaxial compression testing. This workflow provides physics-based solution to complex grain contact behaviour, which complements laboratory core analysis, and can be useful to reveal underlying grain-scale processes governing rock mechanical behaviour.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Free Grain Contactsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Micromechanics Digital Rock: Parameterization of Consolidation Level using a Grain Contact Model

Sun

Salazar-Tio²,

Fager³

et al. 2023

E3S Web Conf.

Self Cite

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“…Reliable prediction of properties of rocks from the pore-scale micro-computed-tomography (micro-CT) images is the defining aim of digital rock physics (DRP) [1,2,3,4,5,6,7,8]. The workflow of DRP starts with the acquisition of pore-scale rock 3D images from micro-CT scans.…”

Section: Introductionmentioning

confidence: 99%

Computation of effective elastic moduli of rocks using hierarchical homogenization

Ahmad¹,

Liu²,

Ortiz³

et al. 2022

Preprint

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This work focuses on computing the homogenized elastic properties of rocks from 3D micro-computed-tomography (micro-CT) scanned images. The accurate computation of homogenized properties of rocks, archetypal random media, requires both resolution of intricate underlying microstructure and large field of view, resulting in huge micro-CT images. Homogenization entails solving the local elasticity problem computationally which can be prohibitively expensive for a huge image. To mitigate this problem, we use a renormalization method inspired scheme, the hierarchical homogenization method, where a large image is partitioned into smaller subimages. The individual subimages are separately homogenized using periodic boundary conditions, and then assembled into a much smaller intermediate image.The intermediate image is again homogenized, subject to the periodic boundary condition, to find the final homogenized elastic constant of the original image. An FFT-based elasticity solver is used to solve the associated periodic elasticity problem. The error in the homogenized elastic constant is empirically shown to follow a power law scaling with exponent −1 with respect to the subimage size across all five microstructures of rocks. We further show that the inclusion of surrounding materials during the homogenization of the small subimages reduces error in the final homogenized elastic moduli while still respecting the power law with the exponent of −1. This power law scaling is then exploited to determine a better approximation of the large heterogeneous microstructures based on Richardson extrapolation.

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Numerical investigation on the effect of bedding plane properties on mode I fracture characteristics of mudstone with FEM-CZM method

Meng

Jing

Yuan³

et al. 2021

Bull Eng Geol Environ

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Prediction of rock elastic moduli based on a micromechanical finite element model

Cited by 8 publications

References 52 publications

Micromechanics Digital Rock: Parameterization of Consolidation Level using a Grain Contact Model

Micromechanics Digital Rock: Parameterization of Consolidation Level using a Grain Contact Model

Computation of effective elastic moduli of rocks using hierarchical homogenization

Numerical investigation on the effect of bedding plane properties on mode I fracture characteristics of mudstone with FEM-CZM method

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