Wettability and capillary pressure direction in TOUGH2
Previous discussions indicate that the direction for Pc is always "pulling" the wetting component toward lower saturation regions. Does TOUGH assume the aqueous phase is always the wetting phase ? If so, do any of the TOUGH modules (or new TOUGH3) have capability for a non-aqueous wetting phase ?
And further, how would you build a simulation in which the choice of wetting component actually actually changes with pressure ?
6 replies
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Buddy,
Yes, water is the wetting phase, NAPL is the intermediately wetting phase, and gas is the non-wetting phase. Not sure what fluid you are dealing with, but oil would be a non-wetting (with respect to water) liquid phase, also in TOUGH2.
Feel free to implement a Pcap function that is positive, and make it pressure dependent.
Stefan
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Late reply for an old post, but I can share an example of an EOS module of TOUGH2 V.2.0 which is able to simulate wettability changes during waterflooding of water-wet oil reservoirs as function of either:
- the concentration of NaCl in the injected water/brine (low salinity waterflooding);
- the concentration of polymer in the injected water/brine (polymer waterflooding).
Wettability alteration from water-wet to oil-wet was implemented in TMGAS (Battistelli and Marcolini, 2009, Intl. J. Greenhouse Gases), the EOS module able to simulate the thermodynamics and compute phase thermophysical properties of water, NaCl, NCGs and hydrocarbons real mixtures to high P&T (1000 bar, 260°C).
Wettability changes are triggered by the concentration of salt or polymer in the injected water/brine. A description of the approach is given in the attached paper by Marcolini et al. (2009, TOUGH Symposium) with reference to the low salinity waterflooding option. This is the only publication made related to the EFIP R&D project sponsored by Eni SpA, the former Italian national oil company.
Alfredo