Undersaturated Oil Formation Volume Factor (Bo,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

NameInput Value - UnitConverted ValueValidity CheckLink to Calculation Page
Solution Gas/Oil Ratio (Rs) Solution GOR at bubble point pressure (scf/STB)
More Details

scf/STB

Oil Gas Solubility (Rs)
Solution Gas Specific Gravity (Rs) More Details

SG

Solution Gas Specific Gravity (ɣg)
Temperature

°R

Pressure

psi

Bubble Point Pressure (Pb) More Details

psi

Bubble Point Pressure (Pb)
Stock Tank Oil Specific Gravity (ɣo)

deg API

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

psi

Separator Temperature Actual separator temperature (two stage separation)
More Details

°R

First Stage Flash GOR

scf/STB

Oil Formation Volume Factor (Bo) Saturated oil formation volume factor (Bo,s)
More Details

bbl/STB

Saturated Oil Formation Volume Factor (Bo,s)
Oil Compressibility (Co) Undersaturated oil isothermal compressibility factor (Co,us)

1/psi

Undersaturated oil isothermal compressibility factor (Co,us)- Saturated Oil isothermal compressibility factor (Co,s)

CALCULATE

Results

CorrelationCalculated ValueWarningsRemarks
1-Petrosky and Farshadbbl/STBGulf of Mexico crude oil system
2-Vasquez and Beggsbbl/STB
3-Hanafy et albbl/STBEgyptian crude oils
4-Arithmetic Averagebbl/STB