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Reservoir EngineeringPVT PropertiesCalculation record

Instantaneous Gas-Oil Ratio Calculator

GOR=Rs+krgμoBokroμgBgGOR = R_s + \frac{k_{rg}\mu_o B_o}{k_{ro}\mu_g B_g}

Enter the declared reservoir engineering inputs below to solve GOR. Variable definitions, units, the default calculation, and the available source trail are included on this page.

Tabular solver

Inputs

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

7 variables

Your input values and calculation stay in this browser.

Extended guidance in preparation

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

GOR=Rs+krgμoBokroμgBgGOR = R_s + \frac{k_{rg}\mu_o B_o}{k_{ro}\mu_g B_g}

Reproducible default result

With the default values shown below, the calculation returns GOR = 3,600 SCF/STB. Defaults demonstrate the implementation; they are not recommended field values.

R_sSCF/STB

600

k_rgdimensionless

0.05

k_rodimensionless

0.4

mu_ocP

2

mu_gcP

0.02

B_obbl/STB

1.2

B_gbbl/SCF

0.005

Input definitions

R_s

SCF/STB

Solution Gas-Oil Ratio

k_rg

dimensionless

Relative Gas Permeability

k_ro

dimensionless

Relative Oil Permeability

mu_o

cP

Oil Viscosity

mu_g

cP

Gas Viscosity

B_o

bbl/STB

Oil Formation Volume Factor

B_g

bbl/SCF

Gas Formation Volume Factor

Output definitions

GOR

SCF/STB

Instantaneous Gas-Oil Ratio

R_s

SCF/STB

Solution Gas-Oil Ratio

k_rg

dimensionless

Relative Gas Permeability

mu_o

cP

Oil Viscosity

B_o

bbl/STB

Oil Formation Volume Factor

k_ro

dimensionless

Relative Oil Permeability

mu_g

cP

Gas Viscosity

B_g

bbl/SCF

Gas Formation Volume Factor

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

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 1, Page 16.

Open source reference