A pore-scale investigation of a multiphase porous media system

Al-Raoush, Riyadh I.; Willson, Clinton S.

doi:10.1016/j.jconhyd.2004.12.001

Cited by 148 publications

(99 citation statements)

References 38 publications

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“…The previously unidentified displacement mechanism has implications for (i) enhanced oil recovery, (ii) remediation of nonaqueous liquid contaminants in aquifers, and (iii) subsurface CO 2 storage. such as bead packs (22), sand packs (22)(23)(24)(25)(26), and sandstones (8,18,21,23), but less attention has been paid to carbonate rocks. However, more than 50% of the world's remaining oil reserves are located in carbonate reservoirs (27), and carbonate aquifers supply water wholly or partially to one quarter of the global population (28).…”

mentioning

confidence: 99%

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Pak

Butler

Geiger

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

150

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Using X-ray computed microtomography, we have visualized and quantified the in situ structure of a trapped nonwetting phase (oil) in a highly heterogeneous carbonate rock after injecting a wetting phase (brine) at low and high capillary numbers. We imaged the process of capillary desaturation in 3D and demonstrated its impacts on the trapped nonwetting phase cluster size distribution. We have identified a previously unidentified pore-scale event during capillary desaturation. This pore-scale event, described as droplet fragmentation of the nonwetting phase, occurs in larger pores. It increases volumetric production of the nonwetting phase after capillary trapping and enlarges the fluid−fluid interface, which can enhance mass transfer between the phases. Droplet fragmentation therefore has implications for a range of multiphase flow processes in natural and engineered porous media with complex heterogeneous pore spaces.droplet fragmentation | X-ray computed microtomography | pore-scale imaging | heterogeneous porous media | carbonate rock M ultiphase fluid displacement processes in porous media are important for a broad range of natural and engineering applications such as transport of nonaqueous phase liquid contaminants in aquifers, oil and gas production from hydrocarbon reservoirs, subsurface CO 2 storage, or gas transport in fuel cells. Herein, capillary trapping is a fundamental mechanism that causes immobilization of a portion of the resident nonwetting phase when it is displaced by an invading wetting phase. As a result, production of the nonwetting phase is always less than 100%.The pore-scale physics of capillary trapping are broadly understood, as the underlying mechanisms such as piston-like displacement, snap-off and film development have been observed in physical micromodel experiments and quantitative theories have been established for them (1-4). The conventional view considers such pore-scale processes to occur between multiple pores, i.e., they are interpore processes and the pores are defined as volumes connected by narrower pore throats. By contrast, intrapore processes, as presented in this paper, are not well established in the literature. During drainage (i.e., where a nonwetting phase displaces the wetting phase), the wetting phase can establish films in the corners of the pores, which results in its continuous production and hence low residual saturations of the wetting phase. During imbibition (i.e., where the wetting phase displaces a nonwetting phase), swelling of the corner wetting films causes snap-off of the nonwetting phase, which results in capillary trapping of the nonwetting phase. The trapped nonwetting phase exists as disconnected ganglia within the pore network. Numerical pore network models have been developed to include these porelevel mechanisms with the aim of predicting the macroscopic flow properties of porous materials such as the structure of the phase distributions, residual saturation, relative permeability functions, and capillary pressure curves. Some of these mod...

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confidence: 99%

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Pak

Butler

Geiger

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

150

View full text Add to dashboard Cite

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“…Al-Raoush and Willson (2005) have produced high-resolution, three-dimensional images of the interior of a multiphase porous system using synchrotron X-ray tomography. The porous medium was imaged at a resolution of 12.46 µm following entrapment of the nonwetting phase at residual saturation.…”

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confidence: 99%

A New Method for Generating Pore-Network Models of Porous Media

2009

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In this study, we have developed a new method to generate a multi-directional pore network for representing a porous medium. The method is based on a regular cubic lattice network, which has two elements: pore bodies located at the regular lattice points and pore throats connecting the pore bodies. One of the main features of our network is that pore throats can be oriented in 13 different directions, allowing a maximum coordination number of 26 that is possible in a regular lattice in 3D space. The coordination number of pore bodies ranges from 0 to 26, with a pre-specified average value for the whole network. We have applied this method to reconstruct real sandstone and granular sand samples through utilizing information on their coordination number distributions. Good agreement was found between simulation results and observation data on coordination number distribution and other network properties, such as number of pore bodies and pore throats and average coordination number. Our method can be especially useful in studying the effect of structure and coordination number distribution of pore networks on transport and multiphase flow in porous media systems.

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“…The simplest segmentation techniques employ global thresholding in which one threshold value is applied to the whole system. Values below the threshold value are designated as one material, and values above are designated to the other material Al-Raoush and Willson (2005).…”

Section: Segmentation and Quantificationmentioning

confidence: 99%

“…Al-Raoush and Willson (2005) used synchrotron X-ray tomographic images of a multiphase porous media system to capture the entrapment of the nonwetting phase at residual saturation. This study provided a framework for using high-resolution three-dimensional imaging to extract the pore network and quantify fluid distributions.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of residual saturation in mixed-wet porous media using a pore-scale approach

Larpudomlert

Torrealba

Karpyn

et al. 2013

J Petrol Explor Prod Technol

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Wettability is an important factor in terms of flow distribution and the amount of oil left behind in a petroleum reservoir after primary, secondary, and tertiary recovery processes. In fact, most alkaline flooding operations are aimed at wettability reversal. Therefore, a good understanding of how wettability, and other relevant factors (e.g., fluid saturation and porosity), affects displacement efficiency and fluid distribution at the pore-scale can lead to successful predictions of flow properties at the macroscale. In this study, pore-scale two-phase fluid flow in a synthetic mixed-wet granular media was investigated using X-ray microCT. Analysis of residual fluid structures in granular media composed of a mixture of glass and plastic beads (ranging from 0.4 to 0.6 mm in diameter) showed that the number of trapped water blobs was 2.4 times greater than that of oil, whereas most of the blobs were between 0.0001 and 0.001 mm 3 in size (i.e., 100 times smaller than in the case of uniform wettability), and were smaller than the mean pore volume (0.03 mm 3 ). The ratio of surface area to blob volume showed a slight tendency of water blobs to wet a higher surface area of the grains than oil blobs, for blob volumes larger than the mean pore size; this phenomenon can be attributed to stronger wetting affinity of the glass grains to the water phase than that of the plastic grains to the oil phase. Furthermore, statistical analysis of the distance between residual oil and water blobs to each solid surface confirms preferential wetting affinity of oil and water to plastic and glass surfaces, respectively.

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A pore-scale investigation of a multiphase porous media system

Cited by 148 publications

References 38 publications

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

A New Method for Generating Pore-Network Models of Porous Media

Experimental investigation of residual saturation in mixed-wet porous media using a pore-scale approach

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