Rock porosity quantification by dual-energy X-ray computed microtomography

Teles, A.P.; Lima, I.; Lopes, Ricardo Tadeu

doi:10.1016/j.micron.2016.02.004

Cited by 24 publications

(14 citation statements)

References 25 publications

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“…In agreement with our observations, these previous studies found that porosity estimates based on the analysis of tomographic data clearly differ from the labora-5 tory measurements by relative deviations up to more than 50 % (e.g. Fusi and Martinez-Martinez, 2013;Lai et al, 2015;Voorn et al, 2015;Teles et al, 2016). A great majority of the applied evaluation methods for tomographic images tend to underestimate porosity compared to laboratory measurements.…”

Section: Discussionsupporting

confidence: 91%

“…Only minor differences between the different lithologies exist. Absolute deviation of porosity is largest for dual energy CT (Teles et al, 2016). Porosity estimates based on tomographic images using synchrotron radiation are slightly better than those based on single energy CT, due to the increased resolution.…”

Section: Discussionmentioning

confidence: 88%

“…To account for the partial-volume effect and sub-resolution porosity, some authors assign multiple thresholds to phases and their mixtures. Then voxels are identified as "sub-voxel porosity" in addition to "pore" and "solid" (Sok et al, 2010;Teles et al, 2016). Advanced image-acquisition techniques, such as dual energy X-ray CT (Alves et al, 2015;Teles et al, 2016) or injection of contrast agents into the sample and multiple scanning (Akin and Kovscek, 2003;10 Klobes et al, 1997;Lu et al, 2000;Mayo et al, 2015), are used to enhance the phase contrast.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating porosity estimates for sandstones based on X-ray micro-tomographic images

Nehler

Stoeckhert

Oelker

et al. 2019

Preprint

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We compare experimentally determined porosity with values derived from X-ray tomography for a suite of eight sandstone varieties covering a porosity range from about 3 to 25 %. In addition, we performed conventional stereological analysis of SEM images and examined thin sections. We investigated the sensitivity of segmentation, the conversion of the tomographic gray-value images representing the obtained X-ray attenuation coefficients into binary images, to (a) resolution of the digital images, (b) denoising filters, and (c) seven thresholding methods. Images of sandstones with porosities of 15 5 to 25 % exhibit a bimodal intensity distribution of the attenuation coefficients, enabling unambiguous segmentation that gives porosity values closely matching the laboratory values. For samples with lower porosities, pores and grains do not separate well in the skewed unimodal intensity histograms. For these samples, all tested thresholding methods tend to miscalculate porosity significantly. In addition to absolute porosity, the ratio between pore size and resolution, and mineralogical composition of the rocks affect the biases of the global segmentation methods.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Evaluating porosity estimates for sandstones based on X-ray micro-tomographic images

Nehler

Stoeckhert

Oelker

et al. 2019

Preprint

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“…Since the development of the x-ray computed tomography (CT) in the early seventies of the last century [1], many applications of this technique have been found in different research domains. CT have been applied with great success in the geosciences, soil science, paleontology, materials science, medicine, plant science, and so on [2][3][4][5][6][7][8]. The technique is based on the interaction of radiation with material being analyzed [9].…”

Section: Introductionmentioning

confidence: 99%

X-ray Microtomography to Quantify Morphological Sandstones Properties

Pires

Melo

Borges

et al. 2019

Braz. arch. biol. technol.

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The sandstones of the Furnas Formation in the State of Paraná, south of Brazil, are located in regions with great importance due to the natural heritage found in the rocky forms and associated flora and fauna. This paper presents a detailed analysis of the internal structure of diverse sandstones of the Furnas Formation. X-ray microtomography allowed 3D characterization of the number, pore size and shape distributions of the sandstones. Images with voxel size of 60 3 µm 3 were utilized to evaluate the sandstone's HIGHLIGHTS • Coarser sandstones presented higher porosities. • Fine sandstones had larger number of pores. • Genetic factors affected the size and shape of pores. • 3D images with voxel size of 60 3 µm 3 were evaluated.

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“…New technologies in laboratory researches together with well-known conventional laboratory techniques on rocks were the basis of detailed rock analysis. Nano-CT (nanocomputed X-ray tomography) with high image resolution is one of the novel techniques, which can be used for evaluation of key reservoir parameters in tight formations (Arns et al 2005;Wennberg et al 2009;Dohnalik 2013;Exner et al 2015;Teles et al 2016). Standard quantitative interpretation algorithms of CT (computed X-ray tomography) image analysis linked to petrophysical information were used in the paper.…”

Section: Introductionmentioning

confidence: 99%

A novel approach to the quantitative interpretation of petrophysical parameters using nano-CT: example of Paleozoic carbonates

et al. 2018

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The main goal was the analysis of parameters describing the structure of the pore space of carbonate rocks, based on tomographic images. The results of CT images interpretation, made for 17 samples of Paleozoic carbonate rocks were shown. The qualitative and quantitative analysis of a pore system was performed. Objects were clustered according to the pore size. Within the clusters, the geometry parameters were analysed. The following dependences were obtained for carbonate rocks, also for individual clusters (due to the volume): (1) a linear relationship (on a bilogarithmic scale) between the specific surface and the Feret diameter and (2) a strong linear relationship between specific surface area and Feret diameter and average diameter of the objects calculated for the sphere. The results were then combined with available results from standard laboratory tests, including NMR and MICP.

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Rock porosity quantification by dual-energy X-ray computed microtomography

Cited by 24 publications

References 25 publications

Evaluating porosity estimates for sandstones based on X-ray micro-tomographic images

Evaluating porosity estimates for sandstones based on X-ray micro-tomographic images

X-ray Microtomography to Quantify Morphological Sandstones Properties

A novel approach to the quantitative interpretation of petrophysical parameters using nano-CT: example of Paleozoic carbonates

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