Phase Behavior and ThermodynamicsPVT Properties
Van der Waals Critical Pressure from Parameters Formula
Van der Waals Critical Pressure from Parameters calculates critical pressure for pvt properties workflows in phase behavior and thermodynamics.
How engineers use this formula
Use this formula when the listed inputs (a_vdw, b_vdw) are known and the assumptions behind the cited pvt 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_c equals 667 psi.
a_vdwpsi*ft^6/lbmol^2
8569.888074689066
b_vdwft^3/lbmol
0.6898311094452774
Inputs
a_vdw
psi*ft^6/lbmol^2van der Waals Attraction Parameter
b_vdw
ft^3/lbmolvan der Waals Covolume Parameter
Outputs
P_c
psi
Critical Pressure
a_vdw
psi*ft^6/lbmol^2
van der Waals Attraction Parameter
b_vdw
ft^3/lbmol
van der Waals Covolume Parameter
Source and review
reviewedChemistry LibreTexts, Condensation of Gases and the Critical State, critical-constant derivation.
Source