Velocity‐dependent capillary pressure in theory for variably‐saturated liquid infiltration into porous media

Hilpert, Markus

doi:10.1029/2012gl051114

Cited by 19 publications

(14 citation statements)

References 21 publications

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“…54,55 This dynamic contact angle is velocity dependent during the displacement process and is quite different from its equilibrium value. 54,55 This dynamic contact angle is velocity dependent during the displacement process and is quite different from its equilibrium value.…”

Section: Dynamic Contact Anglementioning

confidence: 99%

“…Moving fluid-fluid interfaces can generate more pronounced dynamic effects, which causes the variation in dynamic contact angle. 54,55 This dynamic contact angle is velocity dependent during the displacement process and is quite different from its equilibrium value. 54,56 There are two typical models to describe the relationship between the moving velocity and the dynamic contact angle: the hydrodynamic model and the molecular kinetic theory.…”

Section: Dynamic Contact Anglementioning

confidence: 99%

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Dynamic capillarity during displacement process in fractured tight reservoirs with multiple fluid viscosities

Luo

et al. 2019

Energy Science & Engineering

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Dynamic capillarity commonly exists for multiphase flow in porous media, during which fluid viscosity varies and has strong influence. Displacement experiments are conducted on water-wet, fractured tight rock at in situ pressure and temperature of an oil reservoir via a specially designed apparatus to investigate the effects of fluid viscosity on the dynamic capillarity. The dynamic effect in the matrix is examined through the measurement and calculation of capillary pressure, the dynamic coefficient, and the fluid flow behavior. The results show that with a higher oil viscosity:(a) both the steady and the dynamic capillary pressures reverse their directions more quickly and behave as larger resistances in the matrix; (b) the difference between the steady and the dynamic capillary pressures becomes around 5%-19% more significant; (c) water saturation changes more slowly corresponding to the lower water relative permeability, while oil relative permeability quickly becomes lower than that during the basic displacement process; and (d) the dynamic coefficient becomes 2-3 times higher, and the dynamic contact angle becomes 10%-25% larger, showing a more variable interface. A contact angle advancement coefficient is proposed to identify the significance of contact angle advancement and the competition between capillary pressure and viscous force. The findings of this study can help for better understanding of multiphase flow in tight reservoirs and enhancing oil recovery.

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Section: Dynamic Contact Anglementioning

confidence: 99%

Section: Dynamic Contact Anglementioning

confidence: 99%

Dynamic capillarity during displacement process in fractured tight reservoirs with multiple fluid viscosities

Luo

et al. 2019

Energy Science & Engineering

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“…In some cases, this disequilibrium (the difference between capillary pressure and phase pressure difference) is refereed to as ''dynamic capillary pressure'' and is known to be a rate dependent effect [44]. For example, Hilpert [29] used this rate dependent effect to model saturation overshoot at an infiltration front.…”

Section: Introductionmentioning

confidence: 98%

Modeling the velocity field during Haines jumps in porous media

Armstrong

Evseev

Koroteev

et al. 2015

Advances in Water Resources

110

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a b s t r a c tWhen nonwetting fluid displaces wetting fluid in a porous rock many rapid pore-scale displacement events occur. These events are often referred to as Haines jumps and any drainage process in porous media is an ensemble of such events. However, the relevance of Haines jumps for larger scale models is often questioned. A common counter argument is that the high fluid velocities caused by a Haines jump would average-out when a bulk representative volume is considered. In this work, we examine this counter argument in detail and investigate the transient dynamics that occur during a Haines jump. In order to obtain fluid-fluid displacement data in a porous geometry, we use a micromodel system equipped with a high speed camera and couple the results to a pore-scale modeling tool called the Direct HydroDynamic (DHD) simulator. We measure the duration of a Haines jump and the distance over which fluid velocities are influenced because this sets characteristic time and length scales for fluid-fluid displacement. The simulation results are validated against experimental data and then used to explore the influence of interfacial tension and nonwetting phase viscosity on the speed of a Haines jump. We find that the speed decreases with increasing nonwetting phase viscosity or decreasing interfacial tension; however, for the same capillary number the reduction in speed can differ by an order of magnitude or more depending on whether viscosity is increased or interfacial tension is reduced. Therefore, the results suggest that capillary number alone cannot explain pore-scale displacement. One reason for this is that the interfacial and viscous forces associated with fluid-fluid displacement act over different length scales, which are not accounted for in the pore-scale definition of capillary number. We also find by analyzing different pore morphologies that the characteristic time scale of a Haines jump is dependent on the spatial configuration of fluid prior to an event. Simulation results are then used to measure the velocity field surrounding a Haines jump and thus, measure the zone of influence, which extends over a distance greater than a single pore. Overall, we find that the time and length scales of a Haines jump are inversely proportional, which is important to consider when calculating the spatial and temporal averages of pore-scale parameters during fluid-fluid displacement.

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“…However, since that theory also predicts an infinite wetting front velocity at t ¼ 0 [Philip, 1959], it can be expected to exhibit inconsistencies similar to the ones in the classical GA approach, particularly during the early stage of infiltration. It would be interesting to test emerging theories for variably saturated two-fluid flow in porous media that account for a dynamic capillary pressure [Gray and Hassanizadeh, 1991;Eliassi and Glass, 2002;Hassanizadeh et al, 2002;Cueto-Felgueroso and Juanes, 2009;Hilpert, 2012] and that can also model saturation overshoot at an infiltration front.…”

Section: Discussion and Summarymentioning

confidence: 99%

Dynamic capillary pressure during water infiltration: Experiments and Green‐Ampt modeling

Pellichero¹,

Glantz²,

Burns³

et al. 2012

Water Resources Research

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[1] In a recent study by Hsu and Hilpert (2011), the Green-Ampt (GA) model for water infiltration was modified to account for a dynamic capillary pressure that depends on the wetting front velocity. In that study, the only transient flow, to which the modified GA approach was compared, was capillary rise. In this paper, transient downward infiltration experiments were performed using three different ponding depths. We demonstrated that infiltration can be effectively modeled using the modified GA approach. The parameters of the dynamic capillary pressure relationship were fitted and independent of the ponding depth. Furthermore, the experimental data could not be described accurately at early times with the classical GA approach. This was particularly evident when plotting the product between the Darcy velocity and the wetting front position against the wetting front position. In these plots, the initial unphysical infinite rate of infiltration, that occurs in the classical GA model, appears to be a primary element of inaccuracy. It was furthermore verified that the limited ability of the classical GA approach to describe the experimental data is not related to inertial forces arising during the initial phase of infiltration.

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Velocity‐dependent capillary pressure in theory for variably‐saturated liquid infiltration into porous media

Cited by 19 publications

References 21 publications

Dynamic capillarity during displacement process in fractured tight reservoirs with multiple fluid viscosities

Dynamic capillarity during displacement process in fractured tight reservoirs with multiple fluid viscosities

Modeling the velocity field during Haines jumps in porous media

Dynamic capillary pressure during water infiltration: Experiments and Green‐Ampt modeling

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