Phase Behavior and ThermodynamicsGas Properties
Generalized Virial Gas Z-Factor Correlation Formula
Generalized Virial Gas Z-Factor Correlation calculates gas compressibility factor for gas properties workflows in phase behavior and thermodynamics.
How engineers use this formula
Use this formula when the listed inputs (P_pr, T_pr, omega) are known and the assumptions behind the cited gas 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, z equals 0.917827 dimensionless.
P_prdimensionless
3
T_prdimensionless
2
omegadimensionless
0.011
Inputs
P_pr
dimensionlessPseudo-Reduced Pressure
T_pr
dimensionlessPseudo-Reduced Temperature
omega
dimensionlessAcentric Factor
Outputs
z
dimensionless
Gas Compressibility Factor
Source and review
reviewedGeneralized virial coefficient correlation summarized in Bello and Musa 2020 comparative gas z-factor study.
Source