☑️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.

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:

$P_{cgn}$ = $P_{l}$ − $P_{g}$ = gas-NAPL capillary pressure for TMVOC, which is equivalent to $P_{cgl}$ = $P_{l}$ − $P_{g}$ = gaseous CO2-liquid CO2 capillary pressure for ECO2;

$P_{cgl}$ = $P_{l}$ − $P_{g}$ = 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,

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.