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Phase Behavior and ThermodynamicsFluid Properties

Baker-Swerdloff Live-Oil Gas-Oil Interfacial Tension Formula

σo=σod(10.024P0.45)\sigma_o=\sigma_{od}\left(1-0.024P^{0.45}\right)

Baker-Swerdloff Live-Oil Gas-Oil Interfacial Tension calculates live-oil gas-oil interfacial tension for fluid properties workflows in phase behavior and thermodynamics.

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How engineers use this formula

Use this formula when the listed inputs (sigma_od, P) are known and the assumptions behind the cited fluid properties relationship match the engineering case being checked.

Assumptions

  • Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
  • The declared units match the field-unit constants used in the formula.
  • The cited formula applies to the selected petroleum engineering workflow.

Limitations

  • The calculation does not replace a full engineering model or operating procedure.
  • Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.

Common mistakes

  • Mixing unit systems without converting the inputs.
  • Using default example values as field recommendations.
  • Applying the formula outside the source assumptions.

Default example

Using the default inputs, sigma_o equals 10.45554 dynes/cm.

sigma_oddynes/cm

29.439

Ppsia

1500

Inputs

sigma_od

dynes/cm

Dead-Oil Gas-Oil Interfacial Tension

P

psia

Pressure

Outputs

sigma_o

dynes/cm

Live-Oil Gas-Oil Interfacial Tension

C_bs_go

dimensionless

Baker-Swerdloff Gas-Oil Pressure Correction Factor

sigma_od

dynes/cm

Dead-Oil Gas-Oil Interfacial Tension

P

psia

Pressure

Source and review

reviewed

Gas/Oil Interfacial Tension, Baker, O., Swerdloff, W., Pengtools

Baker, O. and Swerdloff, W. 1956. Calculation of Surface Tension 6; Pengtools Gas/Oil Interfacial Tension summary.

Source

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