Fluid-phase topology of complex displacements in porous media

Ott, Holger; Kharrat, Ahmad; Borji, Mostafa; Arnold, Pit

doi:10.1103/physrevresearch.2.023240

Cited by 17 publications

(8 citation statements)

References 29 publications

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“…We also determined the cumulative size distribution of NAPL ganglia P(s) at different velocities for waterflooding and SDS surfactant flooding, where s is the ganglia size, as shown in Figure 12. The P(s) can be obtained by integrating the ganglia size distribution p(s) , and

P (s) = \int_{s}^{\infty} p (x) d x

(Jiang & Tsuji, 2015; Ott et al., 2020). Figure 12 suggests that for both waterflooding and SDS surfactant flooding, most of the NAPL ganglia are smaller than the pore size at all velocities (capillary numbers).…”

Section: Resultsmentioning

confidence: 99%

Effect of Surfactant‐Assisted Wettability Alteration on Immiscible Displacement: A Microfluidic Study

Yang

Brownlow

Walker

et al. 2021

Water Resources Research

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Drainage displacement at unfavorable viscosity ratios is often encountered in oil recovery, CO2 sequestration, and NAPL remediation, which significantly limits recovery of fluids from porous media. Surfactants have been extensively used as wettability modifiers to improve hydrocarbon recovery from rock matrix by imbibition. But little attention has been paid to the effect of surfactant‐assisted wettability alteration on displacement in non‐fractured porous media. In this study, we investigate surfactant‐assisted immiscible displacement in NAPL‐wet microfluidic chips. We find that the change of advancing contact angle by surfactant is velocity dependent. A stable displacement can be achieved at low velocity when wettability‐altering surfactant solution is used as injection fluid. In comparison, fingering occurs at all capillary numbers for water injection, resulting in low NAPL recovery. The generation of NAPL ganglion during waterflooding is significantly different from that during wettability‐altering surfactant flooding. The generation of NAPL ganglion during wettability‐altering surfactant flooding is related to velocity and saturation due to the wettability alteration and interfacial tension reduction. In contrast, the production of NAPL ganglion during waterflooding is only saturation dependent. NAPL ganglia generated during wettability‐altering surfactant flooding are primarily within the pore‐size range and can be easily recovered in subsequent recovery processes. To the best of our knowledge, this study reveals for the first time the pore‐scale mechanism of surfactant‐assisted wettability on the immiscible displacement, which is important for highly efficient NAPL remediation.

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P (s) = \int_{s}^{\infty} p (x) d x

Section: Resultsmentioning

confidence: 99%

Effect of Surfactant‐Assisted Wettability Alteration on Immiscible Displacement: A Microfluidic Study

Yang

Brownlow

Walker

et al. 2021

Water Resources Research

View full text Add to dashboard Cite

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“…Euler characteristic number ( χ ) for a three‐dimensional body is calculated as the linear combination of Betti numbers, χ = b 0 − b 1 + b 2 , where b 0 is the number of isolated objects, b 1 is the number of redundant loops, and b 2 is the number of cavities. Several theoretical (Armstrong et al., 2019; Miller et al., 2019), numerical (McClure et al., 2016, 2018, 2020), and experimental (Armstrong et al., 2016; Herring et al., 2013; Ott et al., 2020; Schlüter et al., 2016) studies have addressed the consideration of the Euler characteristic number as a state variable. Their studies show that Euler characteristic number can provide an improved indication of two‐phase flow and its relevant pore‐scale phenomena.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation of Fluid Connectivity in Two‐Phase Flow in Porous Media During Drainage

Dastjerdi

Karadimitriou

Hassanizadeh

et al. 2022

Water Resources Research

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This study aims to experimentally investigate the possibility of combining two extended continuum theories for two‐phase flow. One of these theories considers interfacial area as a separate state variable, and the other explicitly discriminates between connected and disconnected phases. This combination enhances our potential to effectively model the apparent hysteresis, which generally dominates two‐phase flow. Using optical microscopy, we perform microfluidic experiments in quasi‐2D artificial porous media for various cyclic displacement processes and boundary conditions. Specifically for a number of sequential drainage processes, with detailed image (post‐)processing, pore‐scale parameters such as the interfacial area between the phases (wetting, non‐wetting, and solid), and local capillary pressure, as well as macroscopic parameters like saturation, are estimated. We show that discriminating between connected and disconnected clusters and the concept of the interfacial area as a separate state variable can be an appropriate way of modeling hysteresis in a two‐phase flow scheme. The drainage datasets of capillary pressure, saturation, and specific interfacial area, are plotted as a surface, given by f (Pc, sw, awn) = 0. These surfaces accommodate all data points within a reasonable experimental error, irrespective of the boundary conditions, as long as the corresponding liquid is connected to its inlet. However, this concept also shows signs of reduced efficiency as a modeling approach in datasets gathered through combining experiments with higher volumetric fluxes. We attribute this observation to the effect of the porous medium geometry on the phase distribution. This yields further elaboration, in which this speculation is thoroughly studied and analyzed.

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“…With the development of soil mechanics and frozen soil mechanics, the understanding of soil bodies is getting deeper and deeper (Jiang and Huang, 2016). Soil is a complex multiphase porous medium, and its mechanical properties and equilibrium state are the results of the mutual coupling of the phases in the soil and various environmental effects (Ott et al, 2020;Yan et al, 2022;Guo P. et al, 2021). von Terzaghi (1923) proposed the effective stress principle of saturated soils (Gudehus, 2021), which made soil mechanics independent from general mechanics into an independent discipline and prepared for the improvement of present day soil mechanics (Jiang and Huang, 2018).…”

Section: Introductionmentioning

confidence: 99%

Analysis on “three-box” model of stress-strain in frozen soil porous media based on representative macroscopic Volume

et al. 2022

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In cold regions, the pore space’s composition and phase state can affect the elastic modulus of the media. During the winter, the freezing conditions in the soil results in the release of water from the pore space, which results in significant changes in the media’s distribution and composition. There are a few weaknesses in the current research with respect to the elastic modulus change example of frozen soil. This paper presents that the Representative Macroscopic Volume (RMV) choice strategy is provided for frozen soil with porosity as a typical condition variable. Under the state of freezing, a “three-box” analytical model for stress-strain calculation of frozen soil porous media is established, namely, the black-box model, the gray-box model, and the white-box model. The relevant equations for calculating elastic modulus are presented based on the proposed “three-box” model and the analysis of the stress conduction process. Results show that the discrepancy between the computed and experimental values of the white-box model is slight, and the elastic modulus of frozen soil calculated by the model established in this paper is consistent with the actual state. It can be deduced that the model established in this paper has practicality and the conclusions of the study are of guiding significance for the application of frozen soil.

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Fluid-phase topology of complex displacements in porous media

Cited by 17 publications

References 29 publications

Effect of Surfactant‐Assisted Wettability Alteration on Immiscible Displacement: A Microfluidic Study

Effect of Surfactant‐Assisted Wettability Alteration on Immiscible Displacement: A Microfluidic Study

Experimental Evaluation of Fluid Connectivity in Two‐Phase Flow in Porous Media During Drainage

Analysis on “three-box” model of stress-strain in frozen soil porous media based on representative macroscopic Volume

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