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Phase Behavior and ThermodynamicsPVT Properties

Al-Marhoun Bubble Point Pressure Formula

pb=0.00538088Rsb0.715082γg1.87784γo3.1437(T+459.67)1.32657p_b=0.00538088R_{sb}^{0.715082}\gamma_g^{-1.87784}\gamma_o^{3.1437}(T+459.67)^{1.32657}

Al-Marhoun Bubble Point Pressure calculates bubble point pressure for pvt properties workflows in phase behavior and thermodynamics.

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How engineers use this formula

Use this formula when the listed inputs (R_sb, gamma_g, gamma_o, T) 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, p_b equals 2,511.030937 psi.

R_sbSCF/STB

600

gamma_gfraction

0.8

gamma_ofraction

0.85

T°F

180

Inputs

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

gamma_g

fraction

Gas Specific Gravity

gamma_o

fraction

Stock-Tank Oil Specific Gravity

T

°F

Reservoir Temperature

Outputs

p_b

psi

Bubble Point Pressure

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

Source and review

reviewed

Al-Marhoun, M.A. 1988. PVT Correlations for Middle East Crude Oils, Journal of Petroleum Technology, SPE-13718-PA.

Source

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