Multi-phase classification by a least-squares support vector machine approach  in tomography images of geological samples

Khan, Faisal; Enzmann, Frieder; Kersten, Michael

doi:10.5194/se-7-481-2016

Cited by 17 publications

(10 citation statements)

References 42 publications

(49 reference statements)

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“…Image artefacts were processed as described by Wildenschild and Sheppard (2013). Beam hardening artefacts were removed by applying the best-fit quadratic surface algorithm (Khan et al, 2016) to each reconstructed 2D slice of the image. Ring artefact reduction and image smoothing (with preservation of sharp edge contrasts) were performed using a non-local means filter (Schlüter, 2014).…”

Section: Laboratory and Computational Methods For Rock Characterizationmentioning

confidence: 99%

Benchmark study using a multi-scale, multi-methodological approach for the petrophysical characterization of reservoir sandstones

Haruzi¹,

Katsman²,

Halisch³

et al. 2020

Preprint

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Abstract. This paper presents a detailed description and evaluation of a multi-methodological petrophysical approach for the comprehensive multiscale characterization of reservoir sandstones. The suggested methodology enables the identification of Darcy-scale permeability links to an extensive set of geometrical, textural and topological rock descriptors quantified at the pore scale. This approach is applied to the study of samples from three consecutive sandstone layers of Lower Cretaceous age in northern Israel. These layers differ in features observed at the outcrop, hand specimen, petrographic microscope and micro-CT scales. Specifically, laboratory porosity and permeability measurements of several centimetre-sized samples show low variability in the quartz arenite (top and bottom) layers but high variability in the quartz wacke (middle) layer. The magnitudes of this variability are also confirmed by representative volume sizes and by statistical anisotropy analyses conducted on micro-CT-imaged 3D pore geometries. Two scales of porosity variability are revealed by applying variogram analysis to the top layer: fluctuations at 150 μm are due to variability in the pore size, and those at 2 mm are due to the occurrence of high- and low-porosity bands occluded by iron oxide cementation. This millimetre-scale variability is found to control the laboratory-measured macroscopic rock permeability. Good agreement between the permeability upscaled from the pore-scale modelling and the estimates based on laboratory measurements is shown for the quartz arenite (top) layer. The proposed multi-methodological approach leads to an accurate petrophysical characterization of reservoir sandstones with broad ranges of textural, topological and mineralogical characteristics and is particularly applicable for describing anisotropy at various rock scales. The results of this study also contribute to the geological interpretation of the studied stratigraphic units.

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Section: Laboratory and Computational Methods For Rock Characterizationmentioning

confidence: 99%

Benchmark study using a multi-scale, multi-methodological approach for the petrophysical characterization of reservoir sandstones

Haruzi¹,

Katsman²,

Halisch³

et al. 2020

Preprint

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show abstract

“…Khan et al (2016) and Chauhan et al (2016) support the field of imaging data processing by presenting new research on single-and multi-phase segmentation and classification. Kahl et al (2016) showcase with their paper new technical developments of a new X-ray transparent flow-through reaction cell for the surveillance of hydrothermal mineral-fluid interactions.…”

Section: Content and Highlights Of This Special Issuementioning

confidence: 99%

Pore-scale tomography and imaging: applications, techniques and recommended practice

et al. 2016

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“…achieve the best possible permeability estimation, the differentiation between pore and solid is more important for permeability estimation than the accurate segmentation into different phases (Khan et al 2016). Leu et al (2014) point out that even a small variation in pore throat morphology can have a large impact on the estimation of permeability.…”

Section: Synchrotron-based µXctmentioning

confidence: 99%

Simulating permeability reduction by clay mineral nanopores in a tight sandstone by combining μXCT and FIB-SEM imaging

Jacob¹,

Peltz²,

Hale³

et al. 2020

Preprint

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Abstract. Computer microtomography (µXCT) represents a powerful tool for investigating the physical properties of porous rocks. While calculated porosities determined by this method typically match experimental measurements, computed permeabilities are often overestimated by more than one order of magnitude. This effect increases towards smaller pore sizes, as shown in this study, in which nanostructural features related to clay minerals reduce the permeability of tight reservoir sandstone samples. FIB-SEM tomography was applied to determine the permeability effects of illites at the nanometre scale and Navier-Stokes-equations were applied to calculate the permeability of these domains. With this data, microporous domains (porous voxels) were defined using microtomography images of a tight reservoir sample. The distribution of these domains could be extrapolated by calibration against size distributions measured in FIB-SEM images. For this, we assumed a mean permeability for the dominant clay mineral (illite) in the rock and assigned it to the microporous domains within the structure. The results prove the applicability of our novel approach by combining FIB-SEM with X-ray tomographic rock core scans to achieve a good correspondence between measured and simulated permeabilities. This methodology results in a more accurate representation of reservoir rock permeability in comparison to that estimated purely based on µXCT images.

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Multi-phase classification by a least-squares support vector machine approach in tomography images of geological samples

Cited by 17 publications

References 42 publications

Benchmark study using a multi-scale, multi-methodological approach for the petrophysical characterization of reservoir sandstones

Benchmark study using a multi-scale, multi-methodological approach for the petrophysical characterization of reservoir sandstones

Pore-scale tomography and imaging: applications, techniques and recommended practice

Simulating permeability reduction by clay mineral nanopores in a tight sandstone by combining μXCT and FIB-SEM imaging

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