Saturated Oil Formation Volume Factor (Bo,s)

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.

Bo is always greater than or equal to unity. It should be noted that all the correlations could be used for any pressure equal to or below the bubble-point pressure.

Reference: Reservoir Engineering Handbook, Tarek Ahmed


  • 1-Standing
  • 2-Glaso
  • 3-Marhoun
  • 4-Petrosky and Farshad
  • 5-Vasquez and Beggs
  • 6-Hanafy et al
  • 7-Material Balance

Input Parameters

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


Solution Gas Specific Gravity (ɣg)


Stock Tank Oil Specific Gravity (ɣo)

deg API

Separator Pressure Actual separator pressure (two stage separation)
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Separator Temperature Actual separator temperature (two stage separation)
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First Stage Flash GOR


Oil Density @ (P,T) Density of oil at the specified pressure and temperature
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deg API

Saturated Oil Density (ρo,s)- Saturated Oil Density (ρo,s)



CorrelationCalculated ValueWarningsRemarks
1-Standingbbl/STBCalifornia crude oils and natural gases- Bo range is 1.024 to 2.15 bbl/STB
2-Glasobbl/STBNorth Sea crude oil- Bo range is 1.032 to 2.588 bbl/STB
3-Marhounbbl/STBMiddle Eastern crude oil systems- Bo range is 1.032 to 1.997 bbl/STB
4-Petrosky and Farshadbbl/STBGulf of Mexico crude oil system- Bo range is 1.1178 to 1.6229 bbl/STB
5-Vasquez and Beggsbbl/STBBo range is 1.022 to 2.747 bbl/STB
6-Hanafy et albbl/STBEgyptian crude oils- Bo range is 1.032 to 4.35 bbl/STB
7-Material Balancebbl/STB