Pore-scale simulation of flow of CO2 and brine in reconstructed and actual 3D rock cores

Geophysical Prospecting

2018

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Pore structure heterogeneity is a critical parameter controlling mechanical, electrical and flow transport behaviour of rock. Multi‐fractal analysis method was used for a heterogeneity comparison of three‐dimensional rock samples with different lithology. Six real digital samples, containing three sandstones and three carbonates, were used. Based on the mercury injection capillary pressure test on these samples, we found that the carbonate samples are more heterogeneous than sandstones, but primary results of multi‐fractal behaviours for all samples were similar. We show that if multi‐fractal is used to evaluate and compare heterogeneity of different samples, one needs to follow some considerations such as (1) all samples must have the same size in pixel, (2) samples volume must be bigger than representative volume element, (3) multi‐fractal dimensions should be firstly normalized to a determined porosity value and (4) multi‐fractal results should be interpreted based on resolution of the imaging tool (effects of fine scale sub‐resolution pores are missed). Results revealed that using normalized fractal dimensions, the real samples were divided to less and high heterogeneous groups. Moreover, the study of scale effect also showed that porous structures of these samples are scale invariant in a wide range of scales (from one to eight times bigger).

“…,b; Karimpouli and Tahmasebi , ; Tahmasebi et al . ; Karimpouli et al . , ; Karimpouli, Tahmasebi and Saenger ; Tahmasebi, Sahimi and Andrade ; Tahmasebi ,b; Tahmasebi ,b,c).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

3D multi‐fractal analysis of porous media using 3D digital images: considerations for heterogeneity evaluation

Karimpouli

Geophysical Prospecting

2018

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“…Our work involved using two data sets, Berea sandstone and a synthetic sample, namely a polydisperse sphere-pack; see Figure 1. These data are taken from the available data on Pore-Scale Modeling group at Imperial College University (Dong, 2008 Water Resources Research be modeled through the stochastic algorithms by which one can generate various realizations [Tahmasebi et al, 2017b;Karimpouli and Tahmasebi, 2016;Tahmasebi, 2018c;Tahmasebi, 2017].…”

Section: Discussionmentioning

confidence: 99%

“…The sandstone consisted of 2,074,984 tetrahedral elements, 18,459 edge elements, and 4,313 vertices, while the sphere‐pack has 1,104,097 tetrahedral elements, 11,107 edge elements, and 2,349 vertices. It should be noted that the uncertainty of the initial model can be modeled through the stochastic algorithms by which one can generate various realizations [ Tahmasebi et al, ; Karimpouli and Tahmasebi , ; Tahmasebi , ; Tahmasebi , ].…”

Section: Porous Medium Pore‐scale Imaging and Meshingmentioning

confidence: 99%

Interaction Between Fluid and Porous Media with Complex Geometries: A Direct Pore‐Scale Study

Fagbemi

Water Resources Research

Piri

2018

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Effect of boundary stress on permeability in porous media at pore‐scale is investigated by means of numerical methods for computing deformation of rock material in the presence of pore fluid. We implement a partitioned, strongly coupled solver for transient fluid‐solid simulations with independent conformed interface meshes for the fluid and solid domains. Fluid flow and solid computations were performed using the finite element method. External load is prescribed along the solid boundary in gradual steps to examine the extent of pore‐scale deformation along internal grain walls while applying a fixed constraint at the opposite end to ensure uniform stress distribution across the media. Hydrodynamic interactions between the pore walls and the matrix leading to interface displacements by fluid viscous forces are also investigated by examining fluid flow with different combinations of Reynolds number. Coupling is achieved via traction and displacements boundary conditions at the interface with respect to Lagrangian coordinates. The role of particle shape in the matrix deformation process is also considered in this paper. In order to examine the how particle shape affects local affects local permeability/stress, we examine fluid movement based on varying Reynolds numbers in Berea sandstone obtained from Micro‐CT image scans at high resolution, and artificially constructed random polydisperse 3‐D sphere packs. It was found that permeability alteration under the influence of uniaxial stress was more in the sandstone sample than in the sphere‐pack and that the sphere‐pack deformed less than the actual sample due to pore geometry, surface smoothness, and homogeneity.

“…X‐ray computed tomography, for example, provides valuable information about the spatial distribution and size of the particles [ Cavarretta et al , ], as well as the elastic strains under loading, void ratio in a shear band [ Alshibli and Hasan , ], and the spatial movement of the particles [ Andò et al , ]. Several methods have been proposed to take advantage the 2‐D/3‐D images [ Garboczi , ; Andrade and Tu , ; Andrade et al , ; Lim and Andrade , ; Tahmasebi et al , , , , ]. It is also of interest to produce multiple realizations of any porous medium since, due to the cost and time limitations, one usually has only one or very few images.…”

Section: Introductionmentioning

confidence: 99%

Image‐based modeling of granular porous media

Geophysical Research Letters

Sahimi

Andrade

2017

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We propose a new method of modeling granular media that utilizes a single two‐ or three‐dimensional image and is formulated based on a Markov process. The process is mapped onto one that minimizes the difference between the image and a stochastic realization of the granular medium and utilizes a novel approach to remove possible unphysical discontinuities in the realization. Quantitative comparison between the morphological properties of the realizations and representative examples indicates excellent agreement.