Vasquez-Beggs Undersaturated Oil Formation Volume Factor Formula
Vasquez-Beggs Undersaturated Oil Formation Volume Factor calculates undersaturated 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 (B_ob, c_o, p_b, p) 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 1.31871 RB/STB.
1.327544742813975
0.000013353901772325169
2500
3000
Inputs
B_ob
RB/STBOil Formation Volume Factor at Bubble Point
c_o
1/psiOil Compressibility Above Bubble Point
p_b
psiBubble Point Pressure
p
psiPressure
Outputs
B_o
Undersaturated Oil Formation Volume Factor
B_ob
Oil Formation Volume Factor at Bubble Point
c_o
Oil Compressibility Above Bubble Point
p_b
Bubble Point Pressure
p
Pressure
Source and review
reviewedVasquez and Beggs 1980 oil PVT correlations, as summarized in IHS Harmony / WellTest documentation and PIPESIM fluid-property documentation.
Source