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 (\(P_{\mbox{cow}}\)). The table must be terminated by a / or END. The third column is \(P_{\mbox{cgw}}\) when the GAS_WATER or COMP3 modes are used, and is \(P_{\mbox{cow}}\) for all other modes. 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. \(P_{cgw}\) or \(P_{cow}\) can be constant or decrease as \(S_{w}\) increases.