Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary oil recovery. Numerous mechanisms have been proposed in the literature through which microorganisms facilitate the mobilization of residual oil. Herein, we focus on the MEOR mechanisms of interfacial tension reduction (via biosurfactant) and bioclogging in water-wet...
We report here on recent developments and advances in pore-scale x-ray tomographic imaging of subsurface porous media. Our particular focus is on immiscible multi-phase fluid flow, i.e., the displacement of one immiscible fluid by another inside a porous material, which is of central importance to many natural and engineered processes....
Engineered capillary barriers typically consist of two layers of granular materials designed so that the contrast in material hydraulic properties and sloping interface retain infiltrating water in the upper layer. We conducted two benchtop capillary barrier experiments, followed by interpretation and numerical modeling. The hydraulic parameters for two coarse materials...
This work utilizes synchrotron-based x-ray computed microtomography (x-ray CMT) imaging to quantify
the volume and topology of supercritical carbon dioxide (scCO₂) on a pore-scale basis throughout the
primary drainage process of a 6 mm diameter Bentheimer sandstone core. Experiments were performed
with brine and scCO₂ at 8.3 MPa (1200 psi)...
Abstract: Several models for two-phase flow in porous media identify trapping and connectivity of fluids as an important contribution to macroscale hysteresis. This is especially true for hysteresis in relative permeabilities. The trapping models propose trajectories from the initial saturation to the end saturation in various ways and are often...
Easier access to X-ray microtomography (lCT) 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...
Synchrotron-based tomographic datasets of oil–water drainage and imbibition cycles have been analyzed to quantify phase saturations and interfacial curvature as well as connected and disconnected fluid configurations. This allows for close observation of the drainage and imbibition processes, assessment of equilibrium states, and studying the effects of fluid phase disconnection...
The macroscopic description of the hysteretic behavior of two-phase flow in porous media remains a challenge. It is not obvious how to represent the underlying pore-scale processes at the Darcy-scale in a consistent way. Darcy-scale thermodynamic models do not completely eliminate hysteresis and our findings indicate that the shape of...
The hierarchical organization of aggregates in soil is responsible for the presence of inter and intra-aggregate pores. This research aimed to investigate effects of soil surface liming, considering lime rates of 0, 10 and 15 t ha(-1), on the intra-aggregate porous system of soil aggregates with equivalent diameters of 2-4...
There is no doubt that adhesive penetration plays an important role in wood bondline joint performance and durability; yet, to date there is no direct experimental evidence linking penetration depth with bond performance. This is, in part, because adhesive penetration is commonly assessed with various 2D microscopy techniques that are...
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. Dorthe Wildenschild and Kate Lajtha
for their service and support on my graduate defense committee
Microscale X-ray computed tomography (XCT) is discussed as a technique for identifying 3D adhesive distribution in wood-adhesive bondlines. Visualization and material segmentation of the adhesives from the surrounding cellular structures require sufficient gray-scale contrast in the reconstructed XCT data. Commercial wood-adhesive polymers have similar chemical characteristics and density to wood...
The ability to evaluate the effective permeability of proppant packs is useful in predicting the efficiency of hydraulic fracture installations. In this paper we propose a computational approach combining microimaging data from X-ray computed microtomography, the simulations of flow at pore-scale, and an upscaling process which identifies the effective model...
A major difficulty in modeling multiphase flow in porous media is the emergence of trapped
phases. Our experiments demonstrate that gas can be trapped in either single-pores, multipores, or in large
connected networks. These large connected clusters can comprise up to eight grain volumes and can contain
up to 50%...
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imaging (entrapped gas
bubbles) [Ronen et al., 1986], X-ray microtomography (l-CT) [Wildenschild and
We consider computational modeling of flow with small and large velocities at
porescale and at corescale, and we address various challenges in simulation, upscaling, and modeling.
While our focus is on voxel-based data sets from real porous media imaging, our methodology is
verified first on synthetic geometries, and we analyze...
This paper is included in the Proceedings, Part 1, of the International Conference on Computational Science 2009 (ICCS 2009) held in Baton Rouge, LA, USA, May 25-27, 2009.
Prediction of colloid transport in the subsurface is relevant to researchers in a variety of fields such as contaminant transport, wastewater treatment, and bioremediation. Investigations have traditionally relied on column studies whereby mechanistic inferences must be drawn on the basis of colloid behavior at the outlet. Over the past decade,...
A phenol formaldehyde (PF) adhesive was uniformly tagged with iodine such that it yielded sufficient x-ray computed tomography (XCT) gray-scale contrast for material segmentation in reconstructed wood-composite bondlines. Typically, untagged adhesives are organic and have a similar solid state density as wood cell-walls, and therefore cannot be segmented quantitatively in...