Author
Dorthe Wildenschild
Other affiliations: University of California, Davis, University of Copenhagen, Lawrence Livermore National Laboratory ...read more
Bio: Dorthe Wildenschild is an academic researcher from Oregon State University. The author has contributed to research in topics: Porous medium & Saturation (chemistry). The author has an hindex of 36, co-authored 102 publications receiving 5121 citations. Previous affiliations of Dorthe Wildenschild include University of California, Davis & University of Copenhagen.
Papers published on a yearly basis
Papers
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TL;DR: X-ray microtomographic imaging is a non-destructive technique for quantifying these processes in three dimensions within individual pores, and as reported here, with rapidly increasing spatial and temporal resolution.
968 citations
TL;DR: A combination of advances in experimental techniques and mathematical analysis has made it possible to characterize phase distribution and pore geometry in porous media using non-destructive X-ray computed tomography (CT) as discussed by the authors.
493 citations
TL;DR: In this article, the authors focus on multiclass segmentation and detailed descriptions as to why a specific method may fail together with strategies for preventing the failure by applying suitable image enhancement prior to segmentation.
Abstract: Easier access to X-ray microtomography (μCT) facilities has provided much new insight from high-resolution imaging for various problems in porous media research. Pore space analysis with respect to functional properties usually requires segmentation of the intensity data into different classes. Image segmentation is a nontrivial problem that may have a profound impact on all subsequent image analyses. This review deals with two issues that are neglected in most of the recent studies on image segmentation: (i) focus on multiclass segmentation and (ii) detailed descriptions as to why a specific method may fail together with strategies for preventing the failure by applying suitable image enhancement prior to segmentation. In this way, the presented algorithms become very robust and are less prone to operator bias. Three different test images are examined: a synthetic image with ground-truth information, a synchrotron image of precision beads with three different fluids residing in the pore space, and a μCT image of a soil sample containing macropores, rocks, organic matter, and the soil matrix. Image blur is identified as the major cause for poor segmentation results. Other impairments of the raw data like noise, ring artifacts, and intensity variation can be removed with current image enhancement methods. Bayesian Markov random field segmentation, watershed segmentation, and converging active contours are well suited for multiclass segmentation, yet with different success to correct for partial volume effects and conserve small image features simultaneously.
475 citations
TL;DR: In this article, the authors used synchrotron based X-ray microtomography to investigate unsaturated flow through a glass bead column and found that the fluid-fluid interfacial area increasing as saturation decreases, reaching a maximum at saturations ranging from 20 to 35% and then decreasing as the saturation continues to zero.
Abstract: [1] Multiphase flow and contaminant transport in porous media are strongly influenced by the presence of fluid-fluid interfaces. Recent theoretical work based on conservation laws and the second law of thermodynamics has demonstrated the need for quantitative interfacial area information to be incorporated into multiphase flow models. We have used synchrotron based X-ray microtomography to investigate unsaturated flow through a glass bead column. Fully three-dimensional images were collected at points on the primary drainage curve and on the secondary imbibition and drainage loops. Analysis of the high-resolution images (17 micron voxels) allows for computation of interfacial areas and saturation. Corresponding pressure measurements are made during the course of the experiments. Results show the fluid-fluid interfacial area increasing as saturation decreases, reaching a maximum at saturations ranging from 20 to 35% and then decreasing as the saturation continues to zero. The findings support results of numerical studies reported in the literature.
221 citations
TL;DR: Culligan et al. as discussed by the authors used multiphase lattice Boltzmann simulations of a glass bead porous system to investigate hysteresis in the relationship between capillary pressure, wetting phase saturation and nonwetting-wetting interfacial area per volume (a nw ).
206 citations
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TL;DR: Pore-scale imaging and modelling is becoming a routine service in the oil and gas industry as discussed by the authors, and has potential applications in contaminant transport and carbon dioxide storage, which has been shown to transform our understanding of multiphase flow processes.
1,421 citations
TL;DR: 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.
1,134 citations
TL;DR: X-ray microtomographic imaging is a non-destructive technique for quantifying these processes in three dimensions within individual pores, and as reported here, with rapidly increasing spatial and temporal resolution.
968 citations
TL;DR: In this paper, a review of existing approaches for modeling preferential and non-equilibrium flow and transport in the vadose zone is presented, which range from relatively simplistic models to more complex physically based dual-porosity, dual-permeability, and multi-region type models.
885 citations