Gas/Oil Interfacial Tension

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Gas/Oil Interfacial Tension

Gas/Oil Interfacial Tension correlation was published by Baker and Swerdloff in 1956.

Gas/Oil Interfacial Tension correlation in the PVT software at

Math and Physics

 \sigma_{68} =39 - 0.2571 SG_{oAPI}
 \sigma_{100} =37.5 - 0.2571 SG_{oAPI}
 At\ T<68F,\  \sigma_{od}=\sigma_{68}
 At\ 68F<T<100F,\  \sigma_{od}=\frac{\sigma_{68} + (T - 68) * (\sigma_{100} - \sigma_{68})}{ (100 - 68)}
At\ T>100F,\ \sigma_{od}=\sigma_{100}
 \sigma_{o}=\sigma_{od} \times (1-0.24P^{0.45})

The interfacial tension becomes zero at miscibility pressure. 1 dyne/cm is used for calculations, then it becomes less than 1.

 if (\sigma_{o}<1) \sigma_{o}=1


 P = pressure, psia
 SG_{oAPI} = oil specific gravity, °API
 \sigma_{o} = gas/oil interfacial tension, dynes/cm
 \sigma_{od} = gas/oil interfacial tension for dead oil, dynes/cm
 T = temperature, °F

See also

Gas/Oil Interfacial Tension
Gas/Water Interfacial Tension


Baker, O. and Swerdloff, W. 1955. Calculation of Surface Tension 3—Calculating parachor Values. Oil Gas J. (5 December 1955): 141.
Baker, O. and Swerdloff, W. 1956. Calculation of Surface Tension 6—Finding Surface Tension of Hydrocarbon Liquids. Oil Gas J. (2 January 1956): 125.