EU-Project: Trapping Phenomena for Two-Phase Flow in Porous Media and its representation in Upscaling Procedures

Two-phase flows in porous media are of utmost importance forenvironmental engineers trying to remediate sites contaminated withe.g. hydrocarbons in the subsurface. The presence of rockheterogeneities as occurring in most natural formations influence theflow behaviour significantly and hence complicate the computations.
If the medium is heterogeneous, trapping of one phase (DNAPL) mayoccur at interfaces separating two homogeneous layers having differentpermeabilities. This process, which is mainly due to capillarypressure effects, has been revealed by experiments.
The aim of this project is to establish and investigate amulti-dimensional two-phase porous media flow model that includesinterface trapping phenomena. Once the model is clearly stated, asimplified situation will be studied: a lens embedded into ahomogeneous medium (the cell problem).
First we look for steady state solutions where the DNAPL stays trappedat the interface, and in particular we search for a maximal solutionthat would give the maximal amount of trapped DNAPL.
Next we continue our investigations by seeking non-steady solutions ofthe standard cell problem. This knowledge will be used for ahomogenization based upscaling procedure. The main goal is to proposean effective equation for two phase flow in a porous medium thatcontains many lenses. This model should account for the trappingeffects at the micro-scale.
In recent years, the necessity for incorporating time-depedent termsin the saturation--capillary pressure--relationship has beenproposed. Up to now, most of these relationship are establishedthrough experiments and subsequent parameter fitting.
Therefore another aim of this research is to investigate the frameworkin which time dependent terms may occur during a homogenizationprocedure, and do enhance the physical understanding of this terms.

Helmig, Rainer

Eichel, Hartmut

LH2

09/2003  - 12/2004

This research is supported through a European Community Marie Curie Fellowship

The resarch was carried out in cooperation withC. J. v. Duijn and I. S. Pop from the Applied Analysis Group at the TU Eindhoven.