# B: CAPILLARY PRESSURE FUNCTIONS

The new codes retain the same capillary pressure functions for two-phase or three-phase flow problems. Table lookup and interpolation using the user provided table as a new approach has been introduced in the TUGH4 for both relative permeability and capillary pressure function.

&#x20;The three-phase functions from TMVOC and ECO2 start at *ICP* = 31. If one of the two-phase functions is chosen, the gas-NAPL (for TMVOC) or gaseous  $$CO\_{2}$$-liquid  $$CO\_{2}$$ (for ECO2) capillary pressure will be assumed to be zero. The notation used below is:&#x20;

$$P\_{cgn}$$  = $$P\_{l}$$  − $$P\_{g}$$  = gas-NAPL capillary pressure for TMVOC, which is equivalent to $$P\_{cgl}$$  = $$P\_{l}$$  − $$P\_{g}$$  = gaseous CO2-liquid CO2 capillary pressure for ECO2;&#x20;

$$P\_{cgl}$$  = $$P\_{l}$$  − $$P\_{g}$$   = gas-aqueous capillary pressure for TMVOC, which is equivalent to $$P\_{cga}$$  = $$P\_{l}$$  − $$P\_{g}$$   = gaseous CO2-aqueous capillary pressure for ECO2. It should be noted that *Pcnl* is given by $$P\_{cnl}$$  = $$P\_{cgl}$$  − $$P\_{cgn}$$   for TMVOC,&#x20;

and similarly  $$P\_{cla}$$  = $$P\_{cga}$$  − $$P\_{cgl}$$   for ECO2.  $$S\_{l}$$,  $$S\_{g}$$, and  $$S\_{n}$$ are the saturations of aqueous, gas (or gaseous  $$CO\_{2}$$) and NAPL (or liquid  $$CO\_{2}$$) phases, respectively.
