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Phase Behavior and ThermodynamicsPVT PropertiesCalculation record

Vasquez-Beggs Bubble Point Pressure from Solution GOR Calculator

pb=[RsbC1γgexp⁡(C3API/(T+460))]1/C2p_b=\left[\frac{R_{sb}}{C_1\gamma_g\exp(C_3API/(T+460))}\right]^{1/C_2}

Enter the declared phase behavior and thermodynamics inputs below to solve p_b. Variable definitions, units, the default calculation, and the available source trail are included on this page.

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Inputs

Defaults provide a quick field-unit example for the equation.

7 variables

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What is available in this record

This record provides the functioning calculator, formula, declared variables and units, a reproducible default result, and the available citation metadata. A separately written engineering interpretation has not yet been published for this calculation.

Formula reference

Formula, variables, and default calculation

pb=[RsbC1γgexp⁡(C3API/(T+460))]1/C2p_b=\left[\frac{R_{sb}}{C_1\gamma_g\exp(C_3API/(T+460))}\right]^{1/C_2}

Reproducible default result

With the default values shown below, the calculation returns p_b = 2,500 psi. Defaults demonstrate the implementation; they are not recommended field values.

R_sbSCF/STB

569.1641063395102

T°F

180

APIAPI

35

gamma_gfraction

0.8

C_pb1dimensionless

0.0178

C_pb2dimensionless

1.187

C_pb3dimensionless

23.931

Input definitions

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

T

°F

Reservoir Temperature

API

API

Oil API Gravity

gamma_g

fraction

Gas Specific Gravity

C_pb1

dimensionless

Vasquez-Beggs C1 Coefficient (0.0178 if API > 30; 0.0362 if API <= 30)

C_pb2

dimensionless

Vasquez-Beggs C2 Coefficient (1.1870 if API > 30; 1.0937 if API <= 30)

C_pb3

dimensionless

Vasquez-Beggs C3 Coefficient (23.931 if API > 30; 25.724 if API <= 30)

Output definitions

p_b

psi

Bubble Point Pressure

R_sb

SCF/STB

Solution Gas-Oil Ratio at Bubble Point

Source and record status

Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.

reviewed

Vasquez and Beggs 1980 oil PVT correlations, as summarized in IHS Harmony / WellTest documentation and PIPESIM fluid-property documentation.

Open source reference