Comparison of pore-scale capillary pressure to macroscale capillary pressure using direct numerical simulations of drainage under dynamic and quasi-static conditions

Konangi, Santosh; Palakurthi, Nikhil Kumar; Karadimitriou, Nikolaos; Comer, Ken; Ghia, Urmila

doi:10.1016/j.advwatres.2020.103792

Cited by 18 publications

(9 citation statements)

References 46 publications

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“…When

, capillary fingering or stable displacement can occur. Capillary pressure has an inherent pore-scale nature and is calculated as the pressure difference across the curved interface between two immiscible fluids in equilibrium [ 15 ]:

where

is the pressure of the non-wetting phase and

is the pressure of the wetting phase. The relation between the capillary pressure and the curvature of the interface is given by the Young–Laplace equation [ 9 ]:

where

is the curvature of the interface.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The relation between the capillary pressure and the curvature of the interface is given by the Young–Laplace equation [ 9 ]:

where

is the curvature of the interface. If considering a capillary tube, the equation can be simplified as [ 15 ]:

where

is the contact angle, and r is the radius of the capillary tube. The actual microscale geometry of a porous matrix is however too complex, and it is not possible to account for all the fine details such as the local values of pore width.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Instead, macroscopic models, known as Darcy or continuum scales are used, which average the capillary pressure values over a Representative Elementary Volume (REV), considering a large number of pores. The non-wetting and the wetting phase pressures become the “average” equivalent capillary pressure, and they are all related to the macroscopic saturation of the two phases as [ 15 ]:

…”

Section: Theoretical Backgroundmentioning

confidence: 99%

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Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

et al. 2023

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The understanding of multiphase flow phenomena occurring in porous media at the pore scale is fundamental in a significant number of fields, from life science to geo and environmental engineering. However, because of the optical opacity and the geometrical complexity of natural porous media, detailed visual characterization is not possible or is limited and requires powerful and expensive imaging techniques. As a consequence, the understanding of micro-scale behavior is based on the interpretation of macro-scale parameters and indirect measurements. Microfluidic devices are transparent and synthetic tools that reproduce the porous network on a 2D plane, enabling the direct visualization of the fluid dynamics. Moreover, microfluidic patterns (also called micromodels) can be specifically designed according to research interests by tuning their geometrical features and surface properties. In this work we design, fabricate and test two different micromodels for the visualization and analysis of the gas-brine fluid flow, occurring during gas injection and withdrawal in underground storage systems. In particular, we compare two different designs: a regular grid and a real rock-like pattern reconstructed from a thin section of a sample of Hostun rock. We characterize the two media in terms of porosity, tortuosity and pore size distribution using the A* algorithm and CFD simulation. We fabricate PDMS-glass devices via soft lithography, and we perform preliminary air-water displacement tests at different capillary numbers to observe the impact of the design on the fluid dynamics. This preliminary work serves as a validation of design and fabrication procedures and opens the way to further investigations.

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“…When

where

is the pressure of the non-wetting phase and

is the pressure of the wetting phase. The relation between the capillary pressure and the curvature of the interface is given by the Young–Laplace equation [ 9 ]:

where

is the curvature of the interface.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The relation between the capillary pressure and the curvature of the interface is given by the Young–Laplace equation [ 9 ]:

where

is the curvature of the interface. If considering a capillary tube, the equation can be simplified as [ 15 ]:

where

Section: Theoretical Backgroundmentioning

confidence: 99%

…”

Section: Theoretical Backgroundmentioning

confidence: 99%

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Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

et al. 2023

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“…Moreover, one constitutive surface cannot be used for both transient and steady-state flow conditions [51]. By far, this PDMS micromodel was continuously implemented to compare with other numerical studies by Kunz, et al [212], Nuske, et al [213], Konangi, et al [214], and Yiotis, et al [215].…”

Section: The State-of-art Of the Micromodelsmentioning

confidence: 99%

Transient Two-Phase Flow in Porous Media: A Literature Review and Engineering Application in Geotechnics

Yan

Galindo‐Torres

et al. 2022

Geotechnics

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This work reviews the transient two-phase flow in porous media with engineering applications in Geotechnics. It initially overviews constitutive relationships, conventional theories, and experiments. Then, corresponding limitations are discussed according to conflicting observations and multiphase interfacial dynamics. Based on those findings, the dynamic nonequilibrium effects were so defined, which could also be abbreviated as dynamic/transient effects. Four advanced theories have already been developed to resolve these effects. This review collects them and discusses their pros and cons. In addition, this work further reviews the state-of-art in terms of experimental methods, influential factors in dynamic/transient effects, and modelling performance, as well as micromodel and numerical methods at pore-scale. Last, the corresponding geotechnical applications are reviewed, discussing their applicability in effective stress, shear strength, and deformation. Finally, the entire review is briefed to identify research gaps in Geotechnics.

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“…In an unsaturated porous medium, capillary pressure and saturation are related by a material characteristics—the so-called retention curve —which is known to exhibit substantial hysteresis 8 . The retention curve gives the matrix potential (or capillary pressure) as a function of saturation under equilibrium conditions 9 , 10 . It was shown that the retention curve and other physical properties depend on the volume of the sample 11 – 15 .…”

Section: Introductionmentioning

confidence: 99%

The difference between semi-continuum model and Richards’ equation for unsaturated porous media flow

Vodák

Fürst

Šír

et al. 2022

Sci Rep

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Semi-continuum modelling of unsaturated porous media flow is based on representing the porous medium as a grid of non-infinitesimal blocks that retain the character of a porous medium. This approach is similar to the hybrid/multiscale modelling. Semi-continuum model is able to physically correctly describe diffusion-like flow, finger-like flow, and the transition between them. This article presents the limit of the semi-continuum model as the block size goes to zero. In the limiting process, the retention curve of each block scales with the block size and in the limit becomes a hysteresis operator of the Prandtl-type used in elasto-plasticity models. Mathematical analysis showed that the limit of the semi-continuum model is a hyperbolic-parabolic partial differential equation with a hysteresis operator of Prandl’s type. This limit differs from the standard Richards’ equation, which is a parabolic equation and is not able to describe finger-like flow.

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Comparison of pore-scale capillary pressure to macroscale capillary pressure using direct numerical simulations of drainage under dynamic and quasi-static conditions

Cited by 18 publications

References 46 publications

Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

Transient Two-Phase Flow in Porous Media: A Literature Review and Engineering Application in Geotechnics

The difference between semi-continuum model and Richards’ equation for unsaturated porous media flow

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