Are permeability and capillary pressure lookup saturations correct?

[hosein1984]

I was reading through some of the opm-material codes. Some of the lookup saturations that are used in some of the classes (i.e. EclDefaultMaterial and EclStone1Material) seemed a little odd to me. I hoped you could explain why you are using these saturation:

• The lookup saturation that are used for Pcog (and Krg) is So = 1 - Sg. I always thought that for "Krw and Pcow" lookup Sw and for "Krg and Pcog" lookup Sg is used. If my assumption is correct then based on the fact that your gas/oil table are tabulated against So, I think So = 1 - Sg - Swco would be more appropriate.
• In EclStone1Material, So = 1 - Sg - Swco is used for lookup of Krog but in "updateHysteresis" function So = 1 - Sg is used for Krog. I suppose that "updateHysteresis" needs to be updated.
• In EclDefaultMaterial's "updateHysteresis" method Sw = 1 - Sg is used for updating krwSw. IMHO, krwSw = Sw should be used here. Also in this method So_go = 1 + Sw_ow is used where probably So_go = 1 - Sw_ow would be more accurate.

[andlaus]

opm-material uses the concept of "wetting" and "non-wetting" phases for the fluid-matrix interactions. (relative to a hydrophilic medium.) all curves are always tabulated and scaled using the wetting phase, i.e. water for water-oil and oil for oil-gas.