High-resolution three-dimensional imaging of coal using microfocus X-ray computed tomography, with special reference to modes of mineral occurrence

Golab, Alexandra; Ward, Colin R.; Permana, Asep Kurnia; Lennox, Paul; Botha, Pieter

doi:10.1016/j.coal.2012.04.011

Cited by 138 publications

(53 citation statements)

References 35 publications

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“…The analysis methods used for observing the development of microstructures include thin sections, P-wave velocity analysis, micro-computed tomography (CT) scans, elemental analysis, and others. However, X-ray CT scans are used widely for studies on soils and rocks such as sandstone (Dewanckele et al 2012;Mayo et al 2015), quartz monzonite (Heard 1980), oil mudstone (Yang et al 2011), limestone (Vandersteen et al 2003, granite (Zhao et al 2008), and cracks in coal (Van Geet 2001;Mazumder et al 2006;Meng et al 2011;Yu et al 2010Yu et al , 2012Golab et al 2013;Wang et al 2013;Cai et al 2014), as well as for soil and rocks from Mars Rieder et al 2004).…”

Section: Introductionmentioning

confidence: 98%

Experimental Study of High-Temperature Fracture Propagation in Anthracite and Destruction of Mudstone from Coalfield Using High-Resolution Microfocus X-ray Computed Tomography

Xiao

Wang

et al. 2016

Rock Mech Rock Eng

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The coalfield fire is determined by fractures of coal and rock that provide tunnel for gases and heat exchange. To study fracture propagation at high temperatures, high-resolution X-ray computed tomography (CT) was used to scan anthracite and mudstone samples collected from the Qinshui coalfield, Shanxi Province, northern China. The samples were scanned at 100°C intervals as they were subjected to temperatures of up to 500°C. Three-dimensional images were reconstructed by the CT software to analyze changes in the fractures and pores in the samples. The experimental results show that fracturing of anthracite began at 200°C. The generation rate of fractures in the coal samples increases slowly below 300°C, but above 300°C there is a sharp increase in fracture development. This indicates that the thermal fracturing temperature threshold for anthracite is 300°C. During the experiment, it was found that preexisting fractures, voids, and regenerative fractures formed around the hard portions of anthracite particles or along the weak boundaries between particles. Some regenerative fractures developed along the fabric of the relatively crystalline particles within the particle and terminate at the edge of the particle or where the fracture encounters a harder portion of coal. Some fractures even expanded enough to be transformed into voids as temperatures rose. In the mudstone, the porosity changed suddenly at 300°C. This indicated that there was a void generated at 200°C, but the void expanded when the temperature was increased. However, changes in the void were not obvious from 200 to 300°C.

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Section: Introductionmentioning

confidence: 98%

Experimental Study of High-Temperature Fracture Propagation in Anthracite and Destruction of Mudstone from Coalfield Using High-Resolution Microfocus X-ray Computed Tomography

Xiao

Wang

et al. 2016

Rock Mech Rock Eng

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“…Butt cleats are thought to accommodate relaxation of the stress which originally formed the face cleats. This leads to perpendicularity between both cleat types (Golab et al 2013). Most research has been done on this orthogonal cleat system.…”

Section: Coal Cleat Networkmentioning

confidence: 99%

Image processing based characterisation of coal cleat networks

Busse

Dreuzy

Galindo‐Torres

et al. 2017

International Journal of Coal Geology

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Characterisation of the cleat network serves as the basis for estimating the hydraulic and mechanical seam properties which in turn are fundamental for flow and geomechanical modelling in the context of underground coal mining. Cleat and cleat network geometry can be described as a function of frequency, aperture, size, orientation relative to in situ stresses, connectivity and porosity, with mineralised and un-mineralised cleats occurring. To describe these properties, CTscans of core samples of a Bowen Basin coal in central Queensland, Australia, are analysed.A unique image processing workflow method is introduced to extract the key statistical parameters of perpendicular butt and face cleats present in a two-dimensional image. As face and butt cleats have different characteristics, the presented method distinguishes face cleats and butt cleats by direction and present detailed data for both cleat types. The results comprise cleat length, apertures, sizes, intensities, densities, shape parameter, spacing, orientation and connectivity and are therefore more comprehensive than previous cleat descriptions. Three generally different cleat geometries are considered within this study, one sample shows perpendicular face and butt cleats, the second two sets of face cleats intersected by butt cleats and the third parallel face cleats only.

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“…Voxel, a conventional cubic unit of volume, was used in the micro-CT data analysis. Voxel size decided on the micro-CT method resolution (Golab et al 2013). A gray-scale cross-section, through a sandstone sample is shown in Figure 9A.…”

Section: Fig 8 Exemplary Projections Of the Rotliegend Sandstone Samentioning

confidence: 99%

“…In the referenced literature, there are examples illustrating the application of micro-CT techniques, in order to show inner structure of various materials (Osher & Schladitz 2009, Golab et al 2013, Nadeev et al 2013, among them rocks. In this paper, the Rotliegend rocks were selected to be examined using this new technique to improve reservoir properties determination.…”

Section: Introductionmentioning

confidence: 99%

Determination of reservoir properties through the use of computed X-ray microtomography – eolian sandstone examples

Dohnalik¹,

Jarzyna²

2015

geol

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Abstract:The possibility of examining rock pore structure by the means of computed X-ray microtomography was presented. Parameters characterizing the pore structure, such as: porosity and coefficient of homogeneity of pore structure by local porosity examination, box counting dimension, mean chord length, normalized Euler number, as well as coordination number were all determined through pore structure image analyses. Complementary methods, such as helium pycnometry, mercury injection capillary pressure and NMR were used to determine the porosity along with other factors to make the comparison and determine mutual relationships between petrophysical properties obtained from various sources.The study covered the Rotliegend sandstones of eolian origin. Laboratory investigation of the reservoir properties was focused on three areas, according to their geological regions, where the Rotliegend sediments showed changeability in geological features and reservoir properties. Computed X-ray microtomography showed differentiation between the investigated areas, with respect to their pore structure and porosity development. This differentiation was confirmed by means of other applied laboratory methods.

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High-resolution three-dimensional imaging of coal using microfocus X-ray computed tomography, with special reference to modes of mineral occurrence

Cited by 138 publications

References 35 publications

Experimental Study of High-Temperature Fracture Propagation in Anthracite and Destruction of Mudstone from Coalfield Using High-Resolution Microfocus X-ray Computed Tomography

Experimental Study of High-Temperature Fracture Propagation in Anthracite and Destruction of Mudstone from Coalfield Using High-Resolution Microfocus X-ray Computed Tomography

Image processing based characterisation of coal cleat networks

Determination of reservoir properties through the use of computed X-ray microtomography – eolian sandstone examples

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