X-ray imaging and analysis techniques for quantifying pore-scale structure and processes in subsurface porous medium systems

Wildenschild, D.; Sheppard, Adrian

doi:10.1016/j.advwatres.2012.07.018

Cited by 1,024 publications

(671 citation statements)

References 264 publications

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“…Examples include dynamics of snap‐off in multiphase flow, droplet fragmentation in carbonates, changes in pore structure during rock dissolution and oil shale pyrolysis (Al‐Khulaifi et al, 2017; Andrew et al, 2015; Berg et al, 2014; Blunt et al, 2013; Menke et al, 2016; Pak et al, 2015; Saif et al, 2017; Singh et al, 2017; Wildenschild & Sheppard, 2013). In addition, differential X‐ray imaging can characterize subresolution porosity in the complex pore structures of carbonate rocks (Lin et al, 2016) and visualize and quantify capillary drainage (Lin et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

X‐ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method

Gao

Lin

Bijeljic

et al. 2017

Water Resources Research

100

112

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We imaged the steady state flow of brine and decane in Bentheimer sandstone. We devised an experimental method based on differential imaging to examine how flow rate impacts impact the pore‐scale distribution of fluids during coinjection. This allows us to elucidate flow regimes (connected, or breakup of the nonwetting phase pathways) for a range of fractional flows at two capillary numbers, Ca, namely 3.0 × 10−7 and 7.5 × 10−6. At the lower Ca, for a fixed fractional flow, the two phases appear to flow in connected unchanging subnetworks of the pore space, consistent with conventional theory. At the higher Ca, we observed that a significant fraction of the pore space contained sometimes oil and sometimes brine during the 1 h scan: this intermittent occupancy, which was interpreted as regions of the pore space that contained both fluid phases for some time, is necessary to explain the flow and dynamic connectivity of the oil phase; pathways of always oil‐filled portions of the void space did not span the core. This phase was segmented from the differential image between the 30 wt % KI brine image and the scans taken at each fractional flow. Using the grey scale histogram distribution of the raw images, the oil proportion in the intermittent phase was calculated. The pressure drops at each fractional flow at low and high flow rates were measured by high‐precision differential pressure sensors. The relative permeabilities and fractional flow obtained by our experiment at the mm‐scale compare well with data from the literature on cm‐scale samples.

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Section: Introductionmentioning

confidence: 99%

X‐ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method

Gao

Lin

Bijeljic

et al. 2017

Water Resources Research

100

112

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“…The pore-space was separated into individual pores and throats by first calculating a Euclidean distance map of the pore-space. A separate pore was then defined for each of the catchment basins generated by running the watershed algorithm on this distance map (Beucher and Lanteujoul 1979;Wildenschild and Sheppard 2013). Throats were created across the interfaces between different catchment basins.…”

Section: Dry Scansmentioning

confidence: 99%

“…However, in the last 25 years X-ray microtomography has allowed for direct imaging of the pore-space of rocks, providing input for pore-scale models and allowing for direct experimental investigation of fluid distributions Cnudde and Boone 2013;Wildenschild and Sheppard 2013).…”

mentioning

confidence: 99%

The Imaging of Dynamic Multiphase Fluid Flow Using Synchrotron-Based X-ray Microtomography at Reservoir Conditions

et al. 2015

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Fast synchrotron-based X-ray microtomography was used to image the injection of super-critical CO 2 under subsurface conditions into a brine-saturated carbonate sample at the pore-scale with a voxel size of 3.64 µm and a temporal resolution of 45 s. Capillary pressure was measured from the images by finding the curvature of terminal menisci of both connected and disconnected CO 2 clusters. We provide an analysis of three individual dynamic drainage events at elevated temperatures and pressures on the tens of seconds timescale, showing nonlocal interface recession due to capillary pressure change, and both local and distal (non-local) snap-off. The measured capillary pressure change is not sufficient to explain snap-off in this system, as the disconnected CO 2 has a much lower capillary pressure than the connected CO 2 both before and after the event. Disconnected regions instead preserve extremely low dynamic capillary pressures generated during the event. Snap-off due to these dynamic effects is not only controlled by the pore topography and throat radius, but also by the local fluid arrangement. Whereas disconnected fluid configurations produced by local snap-off were rapidly reconnected with the connected CO 2 region, distal snap-off produced much more long-lasting fluid configurations, showing that dynamic forces can have a persistent impact on the pattern and sequence of drainage events.

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“… Monitoring structural dynamic processes The monitoring of structural dynamic processes requires some technical challenges when using X-ray CT. Preferably, process-oriented experiments are carried out in an X-ray CT system in such a way that no displacement of the sample is needed during different stages of the experiment, resulting in a sequence of 3D images that are perfectly aligned with one another (Wildenschild and Sheppard, 2012). This perfect alignment is often crucial for further analysis.…”

Section:  Multi-scale Imagingmentioning

confidence: 99%

“…In order to overcome this problem, a range of experimental and computational tools have been developed which can assist one in probing the material's structure across the wide range of scales in an integrated fashion (Wildenschild and Sheppard, 2012). Sok et al (2010) and Grader et al (2009) developed multi-scale imaging systems that uses thin sections from the original CT scanned sample or sub-samples, to image it at higher resolutions by means of Xray CT, back-scattered and focussed ion beam scanning electron microscopy to deliver information of the grains and pores at submicron resolutions and combines this information with the data derived from the original CT dataset ( Figure 5).…”

Section:  Multi-scale Imagingmentioning

confidence: 99%

High-resolution X-ray computed tomography in geosciences: A review of the current technology and applications

Cnudde

Boone

2013

Earth-Science Reviews

1,232

700

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Please cite this article as: Cnudde, V., Boone, M.N., "High-resolution X-ray computed tomography in geosciences: a review of the current technology and applications", Earth Science Reviews (2013Reviews ( ), doi: 10.1016Reviews ( /j.earscirev.2013 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T AbstractHigh-resolution X-ray Computed Tomography (HRXCT) or micro-CT (µCT) is a frequently used non-destructive 3D imaging and analysis technique for the investigation of internal structures of a large variety of objects, including geomaterials. Although the possibilities of X-ray micro-CT are becoming better appreciated in earth science research, the demands on this technique are also approaching certain physical limitations. As such, there remains a lot of research to be done in order to solve all the technical problems that occur when higher demands are put on the technique. In this paper, a review of the principle, the advantages and limitations of X-ray CT itself are presented, together with an overview of some current applications of micro-CT in geosciences. One of the main advantages of this technique is the fact that it is a non-destructive characterization technique which allows 4D monitoring of internal structural changes at resolutions down to a few hundred nanometers. Limitations of this technique are the operator dependency for the 3D image analysis from the reconstructed data, the discretations effects and possible imaging artefacts. Driven by the technological and computational progress, the technique is continuously growing as an analysis tool in geosciences and is becoming one of the standard techniques, as is shown by the large and still increasing number of publications in this research area. It is foreseen that this number will continue to rise, and micro-CT will become an indispensable technique in the field of geosciences.

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X-ray imaging and analysis techniques for quantifying pore-scale structure and processes in subsurface porous medium systems

Cited by 1,024 publications

References 264 publications

X‐ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method

X‐ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method

The Imaging of Dynamic Multiphase Fluid Flow Using Synchrotron-Based X-ray Microtomography at Reservoir Conditions

High-resolution X-ray computed tomography in geosciences: A review of the current technology and applications

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