A brief guide to synchrotron radiation-based microtomography in (structural) geology and rock mechanics

Fußeis, Florian; Xiao, Xianghui; Schrank, Christoph; Carlo, Francesco De

doi:10.1016/j.jsg.2014.02.005

Cited by 101 publications

(56 citation statements)

References 135 publications

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“…In the last decade, the Xray micro-computed tomography (micro-XRCT) method became widely available and many modern studies have made use of it to obtain 3-D rock images (e.g. Fusseis et al, 2014). The resolution of micro-XRCT of up to (0.6 µm) 3 (voxel size) is high enough to image the spatial distribution of grains, pores, and pore fluids for a wide variety of rocks (e.g.…”

Section: Introductionmentioning

confidence: 99%

Digital carbonate rock physics

et al. 2016

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Abstract. Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray microcomputed tomography data with two different resolutions in the µm range for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study which we complement with nanoindentation experiments (for local elastic properties). In a first step a non-local mean filter is applied to the raw image data. We then apply different thresholds to identify pores and solid phases. Because of a non-neglectable amount of unresolved microporosity (micritic phase) we also define intermediate threshold values for distinct phases. Based on this segmentation we determine porosity-dependent values for effective P -and S-wave velocities as well as for the intrinsic permeability. For effective velocities we confirm an observed twophase trend reported in another study using a different carbonate data set. As an upscaling approach we use this twophase trend as an effective medium approach to estimate the porosity-dependent elastic properties of the micritic phase for the low-resolution images. The porosity measured in the laboratory is then used to predict the effective rock properties from the observed trends for a comparison with experimental data. The two-phase trend can be regarded as an upper bound for elastic properties; the use of the two-phase trend for low-resolution images led to a good estimate for a lower bound of effective elastic properties. Anisotropy is observed for some of the considered subvolumes, but seems to be insignificant for the analysed rocks at the DRP scale. Because of the complexity of carbonates we suggest using DRP as a complementary tool for rock characterization in addition to classical experimental methods.

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Section: Introductionmentioning

confidence: 99%

Digital carbonate rock physics

et al. 2016

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“…The lattice Boltzmann method has the following advantages: (a) It is easy to implement, unnecessary to solve linear system, easy in parallelization processing; (b) it is able to directly process the complicated geometry by "bound-back" scheme, which is essentially advantageous to process the flow in porous media; (c) with LBM, pore-scale simulation can be carried out with micro-computed-tomography images of the porous media [58,59], and mesh is unnecessary. For instance, Ramstad T, et al used the lattice Boltzmann method to simulate the two-phase flow directly on the digital images of porous rocks and compute the relative permeability [60].…”

Section: Lattice Boltzmann Methodsmentioning

confidence: 99%

Advances in Pore-Scale Simulation of Oil Reservoirs

Wang

et al. 2018

Energies

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Abstract:At the high water cut stage, the residual oil in a reservoir becomes complex and dispersed. Moreover, it is challenging to achieve good predictions of the movement of oil and water in a reservoir according to the macroscopic models based on the statistic parameters of this scenario. However, pore-scale simulation technology based on directly tracking the interaction among different phases can make an accurate prediction of the fluid distribution in the pore space, which is highly important in the improvement of the recovery rate. In this work, pore-scale simulation methods, including the pore network model, lattice Boltzmann method, Navier-Stokes equation-based interface tracking methods, and smoothed particle hydrodynamics, and relevant technologies are summarized. The principles, advantages, and disadvantages, as well as the degree of difficulty in the implementation are analyzed and compared. Problems in the current simulation technologies, micro sub-models, and applications in physicochemical percolation are also discussed. Finally, potential developments and prospects in this field are summarized.

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“…The presence of BH artefacts therefore causes problems in 3-D image processing and hampers correct image analysis and phase quantification due to a biased multi-phase image segmentation process. Such artefacts apply for polychromatic X-ray sources only; more recently, monochromatic synchrotronbased µXCT has been introduced as a powerful tool for effective BH-free visualization of the microstructural features of geomaterials at a voxel resolution down to the submicron level (Fusseis et al, 2014;Leu et al, 2014). However, access to this advanced technique is limited by experimental sites and available beam time.…”

Section: F Khan Et Al: Multi-phase Classificationmentioning

confidence: 99%

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

2016

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Abstract. Image processing of X-ray-computed polychromatic cone-beam micro-tomography (µXCT) data of geological samples mainly involves artefact reduction and phase segmentation. For the former, the main beam-hardening (BH) artefact is removed by applying a best-fit quadratic surface algorithm to a given image data set (reconstructed slice), which minimizes the BH offsets of the attenuation data points from that surface. A Matlab code for this approach is provided in the Appendix. The final BH-corrected image is extracted from the residual data or from the difference between the surface elevation values and the original grey-scale values. For the segmentation, we propose a novel least-squares support vector machine (LS-SVM, an algorithm for pixelbased multi-phase classification) approach. A receiver operating characteristic (ROC) analysis was performed on BHcorrected and uncorrected samples to show that BH correction is in fact an important prerequisite for accurate multiphase classification. The combination of the two approaches was thus used to classify successfully three different more or less complex multi-phase rock core samples.

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A brief guide to synchrotron radiation-based microtomography in (structural) geology and rock mechanics

Cited by 101 publications

References 135 publications

Digital carbonate rock physics

Digital carbonate rock physics

Advances in Pore-Scale Simulation of Oil Reservoirs

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

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