# Black Oil Model Characteristic curves¶

The black oil model requires the definition of two capillary pressure curves, for the interface between the oil and water phases, and the interface of the oil and gas phases. In addition relative permeabilities for the water, gas and the oil must also be specified.

## Black Oil - saturation properties by tables - example¶

In the example below the tables needed to define $$P_{cow}$$, $$K_{rw}$$, $$K_{rg}$$, $$P_{cog}$$, $$K_{row}$$ and $$K_{rog}$$ have been specified. The oil relative permeability defaults to ECLIPSE model. Keywords such as KRW_TABLE are not needed as each saturation property is defined unequivocally.

CHARACTERISTIC_CURVES bo_sat_prop_table_example
TABLE swfn_table
PRESSURE_UNITS Bar
EXTERNAL_FILE swfn_file.dat
END
TABLE sof3_table
EXTERNAL_FILE sof3_file.dat
END
TABLE sgfn_table
PRESSURE_UNITS Pa
EXTERNAL_FILE sgfn_file.dat
END
END


Where the file “swfn_file.dat” contains the water saturation table:

SWFN
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 file “sgfn_file.dat” contains the gas saturation table:

SGFN
0.00 0.00 0.00
0.04 0.00 0.014
0.10 0.02 0.034
0.20 0.10 0.068
0.30 0.24 0.10
0.40 0.34 0.14
0.50 0.42 0.17
0.60 0.50 0.20
0.70 0.81 0.24
0.78 1.00 0.27
/


The file sof3_file.dat contains the oil permeability table:

SOF3
0    0       0
0.2  0       0
0.38 0.00432 0
0.4  0.0048  0.004
0.48 0.05288 0.02
0.5  0.0649  0.036
0.58 0.11298 0.1
0.6  0.125   0.146
0.68 0.345   0.33
0.7  0.4     0.42
0.74 0.7     0.6
0.78 1       1
/