PETROPHYSICAL PROPERTIES DERIVED FROM X-RAY CT IMAGES

2003 ◽  
Vol 43 (1) ◽  
pp. 577 ◽  
Author(s):  
C.H. Arns ◽  
A. Sakellariou ◽  
T.J. Senden ◽  
A.P. Sheppard ◽  
R.M. Sok ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Excellent Agreement ◽  
Ct Images ◽  
Three Dimensions ◽  
Rock Properties ◽  
Experimental Measurements ◽  
Petrophysical Properties ◽  
Tomographic Images ◽  
X Ray ◽  
Wide Range

A micro-CT facility for imaging, visualising and modelling sedimentary rock properties in three dimensions (3D) is described. The facility is capable of acquiring 3D X-ray CT images of full-diameter cores and core plugs at up to 2,0003 voxels with resolutions down to 2μm. This allows the 3D pore-space of a rock to be imaged and, with the aid of SEM, to identify regions of different mineralogy. Computational results are presented which demonstrate that accurate predictions of petrophysical properties can be made directly from the digitised tomographic images. Computations of both formation factor and permeability from micro-tomographic images of Fontainebleau sandstone are shown to be in excellent agreement with experimental measurements over a wide range of porosities. Computed elastic properties for dry and water-saturated conditions are shown to be consistent with the exact Gassmann’s equations and are in excellent agreement with experimental measurements. Experimental measurements of Vp/Vs ratio for cemented sandstone morphologies are very noisy and cannot be used to infer relationships between elastic properties, mineralogy and rock microstructure. Computations on tomographic images show that the Vp/Vs ratio exhibits predictable limiting behavior which holds for any number of solid phases and is insensitive to the manner in which the phases are distributed. This allows the development of more accurate empirical methods for deriving the full velocity-porosity relationship for cemented sands. The results demonstrate the feasibility of combining digitised images with numerical calculations to accurately predict petrophysical properties of individual rock morphologies.

Computation of linear elastic properties from microtomographic images: Methodology and agreement between theory and experiment

Geophysics ◽  
2002 ◽  
Vol 67 (5) ◽  
pp. 1396-1405 ◽  
Author(s):  
Christoph H. Arns ◽  
Mark A. Knackstedt ◽  
W. Val Pinczewski ◽  
Edward J. Garboczi
Keyword(s):  
Elastic Properties ◽  
Excellent Agreement ◽  
Fontainebleau Sandstone ◽  
Linear Elastic ◽  
Numerical Predictions ◽  
Wide Range ◽  
Digitized Images ◽  
Water Saturated ◽  
Dry Water ◽  
Theory And Experiment

Elastic property‐porosity relationships are derived directly from microtomographic images. This is illustrated for a suite of four samples of Fontainebleau sandstone with porosities ranging from 7.5% to 22%. A finite‐element method is used to derive the elastic properties of digitized images. By estimating and minimizing several sources of numerical error, very accurate predictions of properties are derived in excellent agreement with experimental measurements over a wide range of the porosity. We consider the elastic properties of the digitized images under dry, water‐saturated, and oil‐saturated conditions. The observed change in the elastic properties due to fluid substitution is in excellent agreement with the exact Gassmann's equations. This shows both the accuracy and the feasibility of combining microtomographic images with elastic calculations to accurately predict petrophysical properties of individual rock morphologies. We compare the numerical predictions to various empirical, effective medium and rigorous approximations used to relate the elastic properties of rocks to porosity under different saturation conditions.

Linear elastic properties of granular rocks derived from X‐ray‐CT images

2007 ◽  
Author(s):  
Christoph H. Arns ◽  
Mahyar Madadi ◽  
Adrian P. Sheppard ◽  
Mark A. Knackstedt
Keyword(s):  
Elastic Properties ◽  
Ct Images ◽  
X Ray ◽  
Linear Elastic

scholarly journals Material-separating regularizer for multi-energy X-ray tomography

2021 ◽  
Author(s):  
Jacek Gondzio ◽  
Matti Lassas ◽  
Salla-Maaria Latva-Äijö ◽  
Samuli Siltanen ◽  
Filippo Zanetti
Keyword(s):  
Interior Point Method ◽  
Three Dimensions ◽  
Inner Product ◽  
Total Variation Regularization ◽  
Baseline Method ◽  
Attenuation Coefficients ◽  
Penalty Term ◽  
Tomographic Images ◽  
X Ray ◽  
Numerical Tests

Abstract Dual-energy X-ray tomography is considered in a context where the target under imaging consists of two distinct materials. The materials are assumed to be possibly intertwined in space, but at any given location there is only one material present. Further, two X-ray energies are chosen so that there is a clear difference in the spectral dependence of the attenuation coefficients of the two materials. A novel regularizer is presented for the inverse problem of reconstructing separate tomographic images for the two materials. A combination of two things, (a) non-negativity constraint, and (b) penalty term containing the inner product between the two material images, promotes the presence of at most one material in a given pixel. A preconditioned interior point method is derived for the minimization of the regularization functional. Numerical tests with digital phantoms suggest that the new algorithm outperforms the baseline method, Joint Total Variation regularization, in terms of correctly material-characterized pixels. While the method is tested only in a two-dimensional setting with two materials and two energies, the approach readily generalizes to three dimensions and more materials. The number of materials just needs to match the number of energies used in imaging.

Synchrotron-based X-ray tomographic images and segmentation techniques to account for effects of grain contacts and micro-cracks on rock properties

2013 ◽  
Author(s):  
Kathleen Sell ◽  
Claudio Madonna ◽  
Beatriz Quintal ◽  
Marcel Frehner ◽  
Nicola Tisato ◽  
...  
Keyword(s):  
Rock Properties ◽  
Tomographic Images ◽  
X Ray ◽  
Micro Cracks

scholarly journals Correlative 3D x-ray fluorescence and ptychographic tomography of frozen-hydrated green algae

2018 ◽  
Vol 4 (11) ◽  
pp. eaau4548 ◽  
Author(s):  
Junjing Deng ◽  
Yuan Hung Lo ◽  
Marcus Gallagher-Jones ◽  
Si Chen ◽  
Alan Pryor ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Tomographic Reconstruction ◽  
Reconstruction Algorithm ◽  
Three Dimensions ◽  
Light Sources ◽  
X Ray ◽  
Reconstruction Quality ◽  
Wide Range ◽  
Conventional Tomography ◽  
Efficient Data

Accurate knowledge of elemental distributions within biological organisms is critical for understanding their cellular roles. The ability to couple this knowledge with overall cellular architecture in three dimensions (3D) deepens our understanding of cellular chemistry. Using a whole, frozen-hydrated Chlamydomonas reinhardtii cell as an example, we report the development of 3D correlative microscopy through a combination of simultaneous cryogenic x-ray ptychography and x-ray fluorescence microscopy. By taking advantage of a recently developed tomographic reconstruction algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE), we produce high-quality 3D maps of the unlabeled alga’s cellular ultrastructure and elemental distributions within the cell. We demonstrate GENFIRE’s ability to outperform conventional tomography algorithms and to further improve the reconstruction quality by refining the experimentally intended tomographic angles. As this method continues to advance with brighter coherent light sources and more efficient data handling, we expect correlative 3D x-ray fluorescence and ptychographic tomography to be a powerful tool for probing a wide range of frozen-hydrated biological specimens, ranging from small prokaryotes such as bacteria, algae, and parasites to large eukaryotes such as mammalian cells, with applications that include understanding cellular responses to environmental stimuli and cell-to-cell interactions.

X-ray crystallographic studies of protein–ligand interactions

2003 ◽  
Vol 31 (5) ◽  
pp. 973-979 ◽  
Author(s):  
R.A. Palmer ◽  
H. Niwa
Keyword(s):  
Binding Site ◽  
Protein Structures ◽  
Three Dimensions ◽  
Small Samples ◽  
Mistletoe Lectin ◽  
Surface Binding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sugar Binding ◽  
Wide Range

X-ray crystallography enables details of covalent and non-covalent interactions to be analysed quantitatively in three dimensions, thus providing the basis for the understanding of binding of ligands to proteins as well as modes of action such as cell-surface binding. This article is concerned with current methods employed for the X-ray analysis of protein structures complexed with ligands. It deals mainly with ‘what can be done’ in current research, rather than providing details of ‘how to do it’. In recent years significant advances have been made in a variety of techniques: growing protein crystals from very small samples by scanning a wide range of conditions; X-ray intensity data collection and measurement through the use of charge-coupled devices and high-intensity, versatile synchrotron sources; cryo-crystallography which both stabilizes the crystals and provides improved data; methods for analysing and interpreting the structures, dependent, at least in part, on both structural and sequence databases; and improvements in hardware and software. To illustrate the type of results achievable two examples involving protein–sugar interactions are discussed: (i) SNAII (the lectin Sambucus nigra agglutinin-II from elder) N-terminal sugar-binding site where terminal sugar units in a glycosylation chain from a symmetry-related molecule bind and (ii) MLI (mistletoe lectin I) C-terminal sugar-binding site with lactose.

scholarly journals 3D printing of rock analogues in sand: a tool for design and repeatable testing of geomechanical and transport properties

2020 ◽  
Vol 205 ◽  
pp. 04014
Author(s):  
Kevin Hodder ◽  
Sergey Ishutov ◽  
Angel Sanchez ◽  
Gonzalo Zambrano ◽  
Rick Chalaturnyk
Keyword(s):  
3D Printing ◽  
Transport Properties ◽  
Experimental Testing ◽  
Three Dimensions ◽  
Rock Properties ◽  
Homogeneous Material ◽  
Promising Alternative ◽  
Wide Range ◽  
3D Printed ◽  
Binder Saturation

Natural rocks can be heterogeneous due to complex diagenetic processes that affect mineralogy and pore architecture. Correlation of geomechanical and transport properties of rocks in three dimensions can lead to large variances in data when tested experimentally. 3D-printing of rock analogues in sand is a promising alternative for experimental testing that can be used to calibrate variables during geotechnical testing. While 3D-printed sand is a homogeneous material, the parameters for creating grain packing and pore infill can be tuned to mimic specific geomechanical and transport properties. Initially, 3D-printed specimens have a low density due to a loose distribution of grains. Herein, we present our efforts at increasing the density through incorporating a roller in the printing process to compact individual layers. We also propose introduction of a more heterogeneous sand mixture that encompasses a wide range of grain-size distributions. Lastly, a discussion between binder saturation (that infills the pore space) of 3D-printed specimens and the axial strength, dimensional control, and porosity is described within. 3D printing of rock analogues is critical in pursuing rigorous destructive tests required for geotechnical and geological engineering because it can provide repeatable, controlled data on rock properties.

scholarly journals In-situ nanoscale imaging of charge transfer of BiNiO3 under high pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C403-C403
Author(s):  
Wenge Yang ◽  
Yijin Liu ◽  
Junyue Wang ◽  
Wendy Mao ◽  
Ho-kwang Mao
Keyword(s):  
High Pressure ◽  
Thermal Expansion ◽  
Charge Transfer ◽  
Negative Thermal Expansion ◽  
High Energy ◽  
Three Dimensions ◽  
High Energy Resolution ◽  
X Ray ◽  
Wide Range ◽  
Nanoscale Imaging

Over last decades, both synchrotron radiation techniques and high pressure research have made great progress. Advanced synchrotron capabilities with high spatial resolution, high flux, and high energy resolution provides us many new avenues to conduct advanced high pressure researches. In this talk, we will focus on the new developments of the nanoscale imaging techniques on the pressure induced phase separation in three dimensions. BiNiO3 under goes a charge transfer induced phase transition under high pressure or temperature, which shows excellent colossal negative thermal expansion effect [1]. Co-exist of both high density and low density phases over a wide range pressure or temperature plays the key roles on the negative thermal expansion behavior. We utilized a newly developed X-ray absorption near edge spectroscopy tomography method, and successfully resolved the mixture of high/low pressure phases as a function of pressure at tens of nanometer resolution. By choosing incident x-ray energy near Ni absorption edge, the pressure induced valence transition can be mapped at tens of nanometer scale in 3d, which provides crucial information on the HP-LP phase boundary [2]. As temperature driven grain growth upon heating, we can draw fundamental information on the pressure-induced phase growth mechanism.

Experimental Verification of Effect of Size on Drainage Capillary Pressure Computed from Digitized Tomographic Images

2010 ◽  
Vol 1 ◽  
pp. 1-10 ◽  
Author(s):  
O.A. Olafuyi ◽  
A.P Sheppard ◽  
C.H. Arns ◽  
R.M. Sok ◽  
Y. Cinar ◽  
...  
Keyword(s):  
Capillary Pressure ◽  
Network Models ◽  
Ct Images ◽  
Micro Ct ◽  
Tomographic Images ◽  
Core Samples ◽  
Wide Range ◽  
Different Diameters ◽  
Rock Microstructure ◽  
Capillary Pressure Curves

This paper presents comparisons between drainage capillary pressure curves computed directly from 3D micro-tomographic images (micro-CT) and laboratory measurements conducted on the same core samples. It is now possible to calculate a wide range of petrophysical and transport properties directly from micro-CT images or from equivalent network models extracted from these images. Capillary pressure is sensitive to rock microstructure and the comparisons presented are the first direct validation of image based computations. The measured data include centrifuge and mercury injection drainage capillary pressure for fired Berea, Bentheimer and Obernkirchner sandstones and unfired Mount Gambier carbonate. The measurements cover a wide range of porosities and permeabilities. The measurements were made on core samples with different diameters (2.5 cm, 1.5 cm, 1 cm and 0.5 cm) to assess the effect of up-scaling on capillary pressure measurements. The smallest diameter samples were also used to obtain the 3D micro-CT images. Good agreement was obtained between the experimental measurements and direct computations on 3D micro-CT images.

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