Rock, saturation, hysteresis, and salinity#

This page defines the saturation-function expressions, layer-dependent saturation parameters, rock properties, optional hysteresis, and salinity.

Saturation-function expressions#

krw, krn, and pcap are Python expressions for wetting relative permeability, non-wetting relative permeability, and capillary pressure.

krw = "krw * ((sw - swi) / (1.0 - sni - swi)) ** nkrw"
krn = "krn * ((1.0 - sw - sni) / (1.0 - sni - swi)) ** nkrn"
pcap = "pen * ((sw - swi) / (1.0 - swi)) ** (-(1.0 / npen))"

Saturation properties#

Each safu row contains:

Irreducible wetting saturation, swi.
Residual non-wetting saturation, sni.
End-point wetting relative permeability, krw.
End-point non-wetting relative permeability, krn.
Entry pressure in bar, pen.
Wetting relative-permeability exponent, nkrw.
Non-wetting relative-permeability exponent, nkrn.
Capillary-pressure exponent, npen.
Capillary-pressure evaluation threshold.
Number of saturation-table points.

Provide one drainage row per layer. When hysteresis is enabled, append one imbibition row per layer. The complete 18-row example is retained in Complete annotated TOML configuration.

Rock properties#

Each rock row contains horizontal permeability in mD, vertical permeability in mD, and porosity. Provide one row per layer.

rock = [
    [1013.25, 101.325, 0.25],
    [506.625, 50.6625, 0.20],
    [1013.25, 101.325, 0.25],
    [506.625, 50.6625, 0.20],
    [0.10132, 0.01013, 0.10],
    [101.324, 10.1324, 0.20],
    [202.650, 20.2650, 0.20],
    [101.324, 10.1324, 0.20],
    [202.650, 20.2650, 0.20],
]

Hysteresis#

hysteresis is optional. Its first entry selects Killough or Carlson; the second selects Both, Pc, or Kr. Omitting the variable disables hysteresis. In the complete example, imbibition rows change residual saturation to 0.3 and the non-wetting exponent to 4.

hysteresis = ["Killough", "Both"]

Salinity#

salinity adds salt concentration in units of 1e-3 kg-M/kg.

salinity = 2.92