# Undersaturated Oil Formation Volume Factor (B_{o,us})

The oil formation volume factor (Bo) is defined as the ratio of the volume of oil (plus the gas in solution) at the prevailing reservoir temperature and pressure to the volume of oil at standard conditions.

With increasing pressures above the bubble-point pressure, the oil formation volume factor decreases due to the compression of the oil. To account for the effects of oil compression on Bo, the oil formation volume factor at the bubble-point pressure is first calculated, then it is adjusted to account for the effect if increasing the pressure above the bubble-point pressure.

Reference: Reservoir Engineering Handbook, Tarek Ahmed

### Correlations

- 1-Petrosky and Farshad
- 2-Vasquez and Beggs
- 3-Hanafy et al
- 4-Arithmetic Average

### Input Parameters

Name | Input Value - Unit | Converted Value | Validity | Link to Calculation Page | |||
---|---|---|---|---|---|---|---|

Solution Gas/Oil Ratio (R_{s}) Solution GOR at bubble point pressure (scf/STB) More Details | 943 | SCF/STB | Oil Gas Solubility (R_{s}) | ||||

Solution Gas Specific Gravity (R_{s}) More Details | 0.781 | SG | Solution Gas Specific Gravity (ɣ_{g}) | ||||

Temperature | 677.67 | °R | |||||

Pressure | 3200 | psi | |||||

Bubble Point Pressure (P_{b}) More Details | 3045 | psi | Bubble Point Pressure (P_{b}) | ||||

Stock Tank Oil Specific Gravity (ɣ_{o}) | 44.2 | deg API | |||||

Separator Pressure Actual separator pressure (two stage separation) More Details | 200 | psi | |||||

Separator Temperature Actual separator temperature (two stage separation) More Details | 519.67 | °R | |||||

First Stage Flash GOR | 500 | SCF/STB | |||||

Oil Formation Volume Factor (B_{o}) Saturated oil formation volume factor (B _{o,s}) More Details | 1.57 | bbl/STB | Saturated Oil Formation Volume Factor (B_{o,s}) | ||||

Oil Compressibility (C_{o}) Undersaturated oil isothermal compressibility factor (C _{o,us}) | 2.21E-05 | 1/psi | Undersaturated oil isothermal compressibility factor (C | ||||

CALCULATE | |||||||

## Results | |||||||

Correlation | Calculated Value | Warnings | Remarks | ||||

1-Petrosky and Farshad | 1.5783 | bbl/STB | Gulf of Mexico crude oil system | ||||

2-Vasquez and Beggs | 1.5407 | bbl/STB | |||||

3-Hanafy et al | 1.4859 | bbl/STB | Egyptian crude oils | ||||

4-Arithmetic Average | 1.5754 | bbl/STB |