Vasquez-Beggs Saturated Oil Formation Volume Factor Formula
Vasquez-Beggs Saturated Oil Formation Volume Factor calculates saturated oil formation volume factor for pvt properties workflows in phase behavior and thermodynamics.
How engineers use this formula
Use this formula when the listed inputs (R_s, T, API, gamma_gc, A_fvf1, A_fvf2, A_fvf3) 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, B_o equals 1.327545 RB/STB.
569.1641063395102
180
35
0.8
0.000467
0.000011
0.000000001337
Inputs
R_s
SCF/STBSolution Gas-Oil Ratio
T
°FReservoir Temperature
API
APIOil API Gravity
gamma_gc
fractionCorrected Gas Specific Gravity
A_fvf1
dimensionlessVasquez-Beggs A1 Coefficient (4.670e-4 if API > 30; 4.677e-4 if API <= 30)
A_fvf2
dimensionlessVasquez-Beggs A2 Coefficient (1.100e-5 if API > 30; 1.751e-5 if API <= 30)
A_fvf3
dimensionlessVasquez-Beggs A3 Coefficient (1.337e-9 if API > 30; -1.811e-8 if API <= 30)
Outputs
B_o
Saturated Oil Formation Volume Factor
R_s
Solution Gas-Oil Ratio
Source and review
reviewedVasquez and Beggs 1980 oil PVT correlations, as summarized in IHS Harmony / WellTest documentation and PIPESIM fluid-property documentation.
Source