Three-dimensional local porosity analysis of porous media

Biswal, B.; Manwart, C.; Hilfer, R.

doi:10.1016/s0378-4371(98)00111-3

Cited by 96 publications

(65 citation statements)

References 30 publications

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“…We compute P(p, L) as the fraction of subvolumes with one or more percolating paths in each ensemble [Biswal et al, 1998]. For an infinite sample, P(p) is a step function with P(p < p c ) = 0 and P(p > p c ) = 1.…”

Section: Percolation Thresholds From Finite-size Scalingmentioning

confidence: 99%

Pore space percolation in sea ice single crystals

et al. 2009

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[1] We have imaged sea ice single crystals with X-ray computed tomography, and characterized the thermal evolution of the pore space with percolation theory. Between À18°C and À3°C the porosity ranged from 2 to 12% and we found arrays of near-parallel intracrystalline brine layers whose connectivity and complex morphology varied with temperature. We have computed key porosity-dependent functions of classical percolation theory directly from the thermally driven pore space evolution of an individual sample. This analysis is novel for a natural material and provides the first direct demonstration of a connectivity threshold in the brine microstructure of sea ice. In previous works this critical behavior has been inferred indirectly from bulk property measurements in polycrystalline samples. From a finite-size scaling analysis we find a vertical critical porosity p c,v = 4.6 ± 0.7%. We find lateral anisotropy with p c,pll = 9 ± 2% parallel to the layers and p c,perp = 14 ± 4% perpendicular to them. Lateral connectivity is established at higher brine volumes by the formation of thin necks between the brine layers. We relate these results to measured anisotropy in the bulk dc conductivity and fluid permeability using a dual porosity conceptual model. Our results shed new light on the complex microstructure of sea ice, highlighting single crystal anisotropy and a step toward a realistic transport property model for sea ice based on percolation theory. We present full experimental details of our imaging and segmentation methodology based on a phase relation formulation more widely applicable to ice-solute systems.

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Section: Percolation Thresholds From Finite-size Scalingmentioning

confidence: 99%

Pore space percolation in sea ice single crystals

et al. 2009

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“…For equal field sizes, the results are camouflaged by the stochastic heterogeneity effect (Fig. 1a), which can lead to incorrect conclusions (Hilfer, 1992;Biswal et al, 1998;Hu and Stroeven, 2005a,b,d). Factually, stochastic heterogeneity theory (Freudenthal, 1965;Holliday, 1966) demonstrates that information obtained on structure-sensitive properties from descriptors of configuration-sensitive nature will be biased when based on sub-representative designs (Stroeven, 2003;Hu and Stroeven, 2005b), as schematically illustrated in Fig.…”

Section: Methodological Aspectsmentioning

confidence: 98%

Modern Routes to Explore Concrete’s Complex Pore Space

Stroeven¹,

Guo²

2011

Image Anal Stereol

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This paper concentrates on discrete element computer-simulation of concrete. It is argued on the basis of stochastic heterogeneity theory that modern concurrent-algorithm-based systems should be employed for the assessment of pore characteristics underlying durability performance of cementitious materials. The SPACE system was developed at Delft University of Technology for producing realistic schematizations of realcrete for a wide range of other particle packing problems, involving aggregate and fresh cement, and for the purpose of exploring characteristics in the hardened state of concrete, including of the pore network structure because of obvious durability problems. Since structure-sensitive properties are involved, schematization of reality should explicitly deal with the configuration of the cement particles in the fresh state. The paper concentrates on the stereological and mathematical morphology operations executed to acquire information on particle size, global porosity, and on distribution of porosity and of the connected pore fraction as a result of the near neighbourhood of aggregate grains. Goal is to provide information obtained along different exploration routes of concrete's pore space for setting up a pore network modelling approach. This type of methodological papers is scarce in concrete technology, if not missing at all. Technical publications that report on obtained results in our investigations are systematically referred to.

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“…where std(L) is the standard deviation at a given box size L, and / mean (L) is the mean porosity (for the whole stack) determined at a given box size L. The local porosity distribution / is given for a box of size L, centered on a pixel of coordinates x i [16,32,33], by:…”

Section: Sample Representativenessmentioning

confidence: 99%

“…Nota: Other approaches exist, which do not require any skeletonization prior to determining the connected pore paths [32,[44][45][46]. Comparison of these approaches with that chosen here, for its simplicity, will be the subject of future research.…”

Section: Skeletonization and Characterization Of Pore Pathsmentioning

confidence: 99%

Gas Breakthrough Pressure (GBP) through Claystones: Correlation with FIB/SEM Imaging of the Pore Volume

Song

Davy

Tománek

2016

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-This contribution uses six claystone samples imaged by FIB/SEM (Focused Ion Beam/ Scanning Electron Microscopy), within micrometric volumes located in the clay matrix; their 3D connected pore network is identified down to 17-22 nm pore size. All samples are gently dried to minimize damage, and several are impregnated with Poly(Methyl MethAcrylate) (PMMA) resin to avoid further damage during FIB/SEM observations. Three pore volumes out of six are connected between two parallel end surfaces through crack-like pores; two are not connected between any two parallel end surfaces; only one sample has a connected pore network distinct from cracks. By assuming varied pathways for gas to migrate by capillarity through the connected pore volumes (either by taking the shortest path, or through the largest path, or through the most frequent pore size, or by simulating the ingress of a non wetting fluid), we determine the Gas Breakthrough Pressure (GBP) through the initially fully liquid saturated claystone, from these micrometric volumes. The scale change (from the micrometric to the macroscopic scale) is assumed possible without changing the GBP value, and clay/water interactions are not accounted for. By comparison with GBP values measured in the laboratory on centimetric-sized claystone samples, it is concluded that breakthrough occurs most probably by capillary digitation; micro-cracks are the most probable pathways for gas, so that gas does not progress in a homogeneous manner through the claystone, as standard macroscopic finite element models would represent it. For intact claystone, predictions based on the capillary ingress of a non wetting fluid provide a GBP value ranging between 7-14 MPa.Résumé -Corrélations entre Pression de Percée de Gaz (PPG) et imagerie FIB/MEB de roches argileuses (argilites) -Six échantillons de roches argileuses (argilites) sont observés au FIF/MEB (Faisceau d'Ions Focalisé couplé à un Microscope Électronique à Balayage) au sein de volumes micrométriques situés dans la matrice argileuse (seule partie poreuse du matériau). Les échantillons sont séchés de façon à minimiser leur endommagement, et imprégnés ou non de résine polyméthacrylate de méthyle (PMMA) pour les maintenir lors des observations. Le réseau poreux connecté en 3D de ces échantillons est mesuré jusqu'à des tailles de pores de 17-22 nm de diamètre. Trois réseaux poreux sur six sont connectés par des pores de morphologie identique à des fissures ; deux réseaux poreux ne sont pas connectés entre deux faces paralléles de l'échantillon ; un seul réseau poreux (sur six) est connecté par des pores qui ne correspondent pas à des fissures. En supposant différents modes de transport capillaire (via le chemin le plus court, via le chemin le plus large, via la taille de pore la plus fréquente, ou en simulant l'intrusion de fluide non mouillant) à l'échelle de ces réseaux poreux micrométriques, nous déterminons la Pression de Percée de Gaz (PPG) au travers DOI: 10.2516 This is an Open Access article distributed under the terms...

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Three-dimensional local porosity analysis of porous media

Cited by 96 publications

References 30 publications

Pore space percolation in sea ice single crystals

Pore space percolation in sea ice single crystals

Modern Routes to Explore Concrete’s Complex Pore Space

Gas Breakthrough Pressure (GBP) through Claystones: Correlation with FIB/SEM Imaging of the Pore Volume

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