Influence of dynamic factors on nonwetting fluid snap‐off in pores

Deng, Wen; Balhoff, Matthew T.; Cardenas, M. Bayani

doi:10.1002/2015wr017261

Cited by 38 publications

(26 citation statements)

References 32 publications

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“…Numerous studies have shown that dimensionless parameters, such as the capillary number and viscosity ratio, can influence displacement flow patterns and thus capillary pressure and relative permeability functions (Aggelopoulos & Tsakiroglou, ). A sufficiently large local CA can inhibit snap‐off (an important dynamic multiphase flow phenomenon) of multiple fluids (Deng et al, ). The motion of a drop through a constriction is therefore relatively steady, but the flow is clearly unsteady in the pore networks of a medium (Olbricht, ).…”

Section: Introductionmentioning

confidence: 99%

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Li¹,

He²,

et al. 2019

Water Resources Research

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In efforts to reduce uncertainties about effects of minor changes in the pore structure of porous media on dynamic nonequilibrium effects (DNEs), we monitored water saturation‐capillary pressure relationships in both dynamic flow and static states in stepwise drainage processes of a sandy medium. The acquired data were used to detect DNE and their changes with time in each drainage step and construct new parameters to characterize DNE. Effects of factors affecting water flow—including capillary number, water saturation, rate of change of water saturation with time (△Sw/△t), and the maximum value of this rate (RSMAX)—on the magnitude of the DNE were then determined. Results show that entry pressures are considerably larger under dynamic flow conditions than under static flow conditions, and DNE only occurs when the water saturation exceeds a threshold value in a drainage process. During either a smooth drainage or drainage step, the maximum capillary pressure (PMAX) is reached before the minimum water saturation (SMIN). Moreover, in drainage steps RSMAX occurs before the maximum difference between the capillary pressures associated with the static and dynamic states (DPMAX), except when they start from the saturated state. Accordingly, DNEs in a drainage step are mainly reflected in the time between PMAX and SMIN (△t), DPMAX, the average sum of the squares of the difference between capillary pressures of the static and dynamic states (DPAVE), and the dynamic coefficient τ (which is often used to characterize DNE). Furthermore, our results indicate that the water saturation and its rate of change with time are more important parameters than the capillary number for modeling DNE in a drainage process, and we detected no clear correlation between either maximum or minimum values of τ and the timing of the most significant DNE during drainages. τ appears to characterize DNE effectively in smooth drainage processes, while △t, DPAVE, and DPMAX constitute meaningful supplementary parameters for the characterization of DNE in a drainage step of a stepwise drainage.

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Section: Introductionmentioning

confidence: 99%

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Li¹,

He²,

et al. 2019

Water Resources Research

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“…A uniform thickness of the wetting film δ * was considered throughout the capillary wall as an initial condition (see Fig. 1); which was calculated using the fitting made by Deng et al (2015) of Beresnev et al (2011b) experimental data. This fitting was established as a function of the local capillary number as δ * =0.0412log10(Ca)+0.1475, and is valid in the range of 3×10 -4 ≤ Ca ≤ 1×10 -2 .…”

Section: Governing Equationsmentioning

confidence: 99%

“…This fitting was established as a function of the local capillary number as δ * =0.0412log10(Ca)+0.1475, and is valid in the range of 3×10 -4 ≤ Ca ≤ 1×10 -2 . In the simulations presented here, we explored the same ranges of dimensionless geometric variables that Deng et al (2015) did, namely: 2 ≤ L ≤16 and 0.20 ≤ a ≤ 0.50. The maximum dimensionless simulation time was also established in τmax= 2×10 5 .…”

Section: Governing Equationsmentioning

confidence: 99%

“…Recently, in a numerical study Deng et al (2015) prove the existence of an upper limit of the local capillary number in which snap-off is inhibited, even if the geometric breakup criteria are met (for example that of Beresnev et al 2009). Although a broad range of geometries was covered in the study of Deng et al (2015), their analysis has been limited to the study of a system where the viscosity ratio was equal to unity. Furthermore, these authors attribute the snap-off inhibition to the critical conditions that arise due to the presence of fast flow in the pores, related to the local capillary number increases, which prevent the growth of the wetting film in the pore constriction.…”

Section: Introductionmentioning

confidence: 99%

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Snap-Off Criteria for Dynamic Flow Conditions in Constricted Circular Capillaries

Tiznado¹,

Fuentes²,

González-Sosa³

et al. 2018

JAFM

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One of the main mechanisms of emulsion formation in porous media is the snap-off; invasion of the wetting phase flowing adjacent to the pore wall within a constriction mostly occupied by the non-wetting phase, causing breakup into isolated drops of this phase. The current approaches to determine the occurrence of this phenomenon have been formulated for quasistatic flow conditions, where the mechanisms governing the flow are controlled by the geometry of the capillary. However, some studies suggest that the drop breakup does not occur above a capillary number threshold and given a certain viscosity ratio, even if the static breakup criteria are met. In this paper, we extend the current numerical analysis of the capillary number upper limit (Calim), in which the snap-off is inhibited, by considering the effect of viscosity ratio on the dynamics of immiscible two-phase flow through constricted circular capillaries. Based on the results of this study, empirical mathematical expressions that relate the main physical variables of the flow were established as breakup criteria for dynamic flow conditions. The dynamic breakup criteria takes into account, jointly: some aspects of rheology of the two-phase system, such as the viscosity ratio; the dynamic factors of the flow, encapsulated in the local capillary number; and an integral form of the capillary geometry, represented by a parameter that relates both radii and the distance between them.

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“…Accurate estimation of trapped, nonmobile, nonwetting phase fluid in the subsurface is a critical parameter for engineering processes such as enhanced oil recovery, geologic CO 2 sequestration, and contaminant remediation. To this end, many previous studies have attempted to link trapping levels to porous media structural characteristics (e.g., Chatzis & Morrow, 1984;Li & Wardlaw, 1986b;Wardlaw & Li, 1988), in addition to fluid-fluid interactions (e.g., Bennion & Bachu, 2013;Kimbrel et al, 2015;Morrow et al, 1988) and dynamic influences (Deng et al, 2015;Singh et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Topological Persistence for Relating Microstructure and Capillary Fluid Trapping in Sandstones

Herring

Robins

Sheppard

2019

Water Resources Research

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Results from a series of two‐phase fluid flow experiments in Leopard, Berea, and Bentheimer sandstones are presented. Fluid configurations are characterized using laboratory‐based and synchrotron based 3‐D X‐ray computed tomography. All flow experiments are conducted under capillary‐dominated conditions. We conduct geometry‐topology analysis via persistent homology and compare this to standard topological and watershed‐partition‐based pore‐network statistics. Metrics identified as predictors of nonwetting fluid trapping are calculated from the different analytical methods and are compared to levels of trapping measured during drainage‐imbibition cycles in the experiments. Metrics calculated from pore networks (i.e., pore body‐throat aspect ratio and coordination number) and topological analysis (Euler characteristic) do not correlate well with trapping in these samples. In contrast, a new metric derived from the persistent homology analysis, which incorporates counts of topological features as well as their length scale and spatial distribution, correlates very well (R2 = 0.97) to trapping for all systems. This correlation encompasses a wide range of porous media and initial fluid configurations, and also applies to data sets of different imaging and image processing protocols.

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Influence of dynamic factors on nonwetting fluid snap‐off in pores

Cited by 38 publications

References 32 publications

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Snap-Off Criteria for Dynamic Flow Conditions in Constricted Circular Capillaries

Topological Persistence for Relating Microstructure and Capillary Fluid Trapping in Sandstones

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