Bubble Point Pressure (Pb)

The bubble point pressure (Pb) of a hydrocarbon system is defined as the highest pressure at which a first bubble of gas is liberated from the oil.

The bubble point pressure is mainly a strong function of gas solubility (Rs), gas gravity (γg), oil gravity (API), and temperature (T).

Reference: Reservoir Engineering Handbook, Tarek Ahmed


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

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 Specifc Gravity (ɣg) Weighted average of the separated gas specific gravities from each separator
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Solution Gas Specific Gravity (ɣg)


Stock Tank Oil Specific Gravity (ɣo) More Details

deg API

Saturated Oil Density (ρo,s)
Separator Pressure Actual separator pressure (first stage separator pressure at two stage separation)
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Separator Temperature Actual separator temperature (first stage separator temperature at two stage separation)
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First Stage Flash GOR GOR of 1st separator in two stage separation




CorrelationCalculated ValueWarningsRemarks
1-StandingpsiCalifornia crude oils and natural gases- Pb range is 130 to 7000 Psia
2-GlasopsiNorth Sea crude oil- Pb range is 1800 to 7130 Psia
3-MarhounpsiMiddle Eastern crude oil systems- Pb range is 130 to 3573 Psia
4-Petrosky and FarshadpsiGulf of Mexico crude oil system- Pb range is 1500 to 6500 Psia
5-Velarde et alpsiPb range is 70 to 6700 Psia
6-ValkopsiWorldwide- Pb range is 82 to 6700 Psia
7-Vasquez and BeggspsiPb range is 15 to 6055 Psia
8-Hanafy et alpsiEgyptian crude oils- Pb range is 36 to 5000 Psia