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| Titel |
Interplay between the capillary pressure, saturation and interfacial area: pore-network analysis |
| VerfasserIn |
Vahid Joekar-Niasar, S. Majid Hassanizadeh |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048818
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| Zusammenfassung |
| Based on rational thermodynamics, Hassanizadeh and Gray [1] have suggested that the
non-uniqueness in the capillary pressure-saturation (Pc-Sw) relationship is indeed due to the
absence of specific interfacial area, which is defined as the total interfacial area divided by the
volume. They introduced interfacial area as a separate thermodynamic entities, possessing
mass, momentum, and energy. They proposed the following equation for capillary
pressure:
F(Pc, Sw, anw) = 0
Understanding the behavior of fluid-fluid interfacial area regardless of the theoretical
aspects is of great important to the mass transfer applications such as CO2 sequestration.
A number of computational and experimental works have shown that under a wide range
of drainage and imbibition histories under equilibrium conditions, Pc-Sw-anw surfaces more
or less coincide. However, uniqueness of Pc-Sw-anw surface under non-equilibrium
conditions is an unanswered question.
We employ a dynamic pore-network simulator as a pore-scale physical-based model.
Computational and geometrical details of this DYnamic POre-network SImulator for
Two-phase flow (DYPOSIT) are given in [2, 3]. DYPOSIT model can simulate transient
behaviour of flow for various capillary numbers and viscosity ratios.
In this study, we simulate primary and main drainage, main imbibition and several
drainage and imbibition scanning curves for three pairs of fluids. These pairs of fluids will
have viscosity ratios equal to 0.1, 1, and 10 under dynamic and quasi-static conditions.
For all dynamic and quasi-static conditions we will calculate averaged capillary
pressure (within an REV), and specific interfacial area (anw) for a given saturation
(Sw).
Results of these simulations will provide Pc-Sw-anw data points under different
dynamic conditions. Results obtained from quasi-static simulations will be used to
generate Pc-Sw-anw surfaces for drainage and imbibition separately. The relative error
between these surfaces will be used as a criterion for comparing with the surfaces
obtained from dynamic simulations. Furthermore, Pc-Sw-anw surfaces will be created
for drainage and imbibition data points resulted from dynamic conditions and the
discrepancies between these surfaces and the average quasi-static surface will be calculated.
This statistical analysis will show to what extent the capillary pressure, saturation,
interfacial area surface are directly correlated under equilibrium and non-equilibrium
conditions.
[1] Hassanizadeh, S. M., and W. G. Gray (1993), Toward an improved description of the
physics of two-phase flow., Advances in Water Resources, 16, 53–67.
[2] Joekar-Niasar, V., S. M. Hassanizadeh, and H. K. Dahle (2010), Non-equilibrium
effects in capillarity and interfacial area in two-phase flow: Dynamic pore-network
modelling, Journal of Fluid Mechanics, 655, 38–71.
[3] Joekar-Niasar, V., and S. M. Hassanizadeh (2010), Effect of fluids properties on
non-equilibrium capillarity effects; dynamic pore-network modelling, International Journal of
Multiphase Flow, doi:10.1016/j.ijmultiphaseflow.2010.09.007 |
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