Phase Behavior and ThermodynamicsGas Properties
Pseudo-Reduced Gas Properties from Critical Properties Formula
Pseudo-Reduced Gas Properties from Critical Properties calculates pseudo-reduced pressure for gas properties workflows in phase behavior and thermodynamics.
How engineers use this formula
Use this formula when the listed inputs (P, P_pc, T, T_pc) 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, P_pr equals 4.477612 dimensionless.
Ppsia
3000
P_pcpsia
670
T°R
640
T_pc°R
375
Inputs
P
psiaPressure
P_pc
psiaPseudo-Critical Pressure
T
°RTemperature
T_pc
°RPseudo-Critical Temperature
Outputs
P_pr
dimensionless
Pseudo-Reduced Pressure
T_pr
dimensionless
Pseudo-Reduced Temperature
Source and review
reviewedPenn State PNG 301. Natural Gas Properties, Equations 3.58 and 3.59.
Source