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| Titel |
Modeling of averaged saturation for immiscible displacement on a continuum scale |
| VerfasserIn |
Insa Neuweiler, Diogo Bolster, Marco Dentz, Tycho van Noorden |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042052
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| Zusammenfassung |
| The fluid-fluid interface during immiscible displacement has a strong influence on mass transfer during the flow process in porous media. Interfaces are here meant as transition zones on a continuum scale, where the pore space is averaged out, which are characterized by strong gradients of the variables (in this case fluid content). In heterogeneous media the interface of the displacement front is spread due to the heterogeneous structure. Important criteria to be captured in upscaled models are therefore the front roughness and the averaged saturation at the front. These two measures are not equivalent, as the averaged saturation captures also patches of trapped or immobile displaced fluid, which is not captured in the front roughness.
The roughening of the front has been analyzed in the past using, for example, stochastic averaging of spatial moments of the saturation distribution in horizontal displacement problems. It has been found that the spreading of the front may, depending on the stability of the flow problem, in average be captured by a dispersive term in the mass conservation equation. We will present results for the spreading during vertical displacement with buoyancy forces. We present also a concept to model the influence of trapped or immobile displaced fluid in an upscaled displacement model for a simple heterogeneous medium structure using homogenization theory. The trapping results in a contribution to the flow equation, which is non-local in time (double continuum model). We demonstrate how this approach can be extended to more complex configurations of heterogeneous medium structure. |
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