# SWFN¶

The SWFN is followed by a table with three columns, in which the first is the water saturation ($$S_w$$), the second is the water relative permeability ($$K_{rw}$$), and the third is the capillary pressure between the gas and water ($$P_{\mbox{cgw}}$$), or between oil and the water phase ($$P_{cow}$$ ). The table must be terminated by a / or END. An example is shown below:

SWFN
0.05 0    0.7
0.22 0    0.48
0.3  0.07 0.27
0.4  0.15 0.2
0.5  0.24 0.17
0.6  0.33 0.14
0.8  0.65 0.07
0.9  0.83 0.03
1    1    0
/

The first saturation entry in the table is the water connate saturation, $$S_{wco}$$ (0.05 in this example). The largest water saturation value for which the water relative permeability is zero is the water residual saturation, $$S_{wcr}$$ (0.22 in this example). The last water saturation entry is the maximum water saturation, $$S_{w,\mbox{max}}$$ (usually 1 as in the example above). $$S_{w}$$ must increase monotonically. $$K_{rw}$$ can be constant or increase as $$S_{w}$$ increases. $$P_{cow}$$ can be constant or decrease as $$S_{w}$$ increases.