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Phase Behavior and ThermodynamicsPVT Properties

Glaso Bubble Point Pressure Formula

pb=101.7669+1.7447log10(pb)0.30218[log10(pb)]2p_b=10^{1.7669+1.7447\log_{10}(p_b^*)-0.30218[\log_{10}(p_b^*)]^2}

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

Calculate

How engineers use this formula

Use this formula when the listed inputs (R_sb, gamma_g, API, 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 2,706.411959 psi.

R_sbSCF/STB

600

gamma_gfraction

0.8

APIAPI

35

T°F

180

Inputs

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

gamma_g

fraction

Gas Specific Gravity

API

API

Oil API Gravity

T

°F

Reservoir Temperature

Outputs

p_b

psi

Bubble Point Pressure

p_b_star

dimensionless

Glaso Bubble Point Correlating Parameter

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

Source and review

reviewed

Glaso, O. 1980. Generalized Pressure-Volume-Temperature Correlations, Journal of Petroleum Technology, SPE-8016-PA.

Source

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