Fraction of the total solution gas retained in the reservoir as free gas
Input(s)
\(\mathrm{N}\): Oil in Place \((\mathrm{STB})\)
\(\mathrm{R}_{\mathrm{p}}\): Produced Gas-Oil Ratio (SCF/STB)
\(\mathrm{N}_{\mathrm{p}}\): Cumulative Oil Production (STB)
\(\mathrm{R}_{\mathrm{si}}\): Initial Gas Solubility \((\mathrm{SCF} / \mathrm{STB})\)
\(\mathrm{R}_{\mathrm{s}}\): Gas Solubility \((\mathrm{SCF} / \mathrm{STB})\)
Output(s)
\(\alpha_{\mathrm{g}}\): Retained Gas Volume of the Total Gas (fraction)
Formula(s)
\[
\alpha_{\mathrm{g}}=1-\left(\frac{\mathrm{N}_{\mathrm{p}} * \mathrm{R}_{\mathrm{p}}}{\mathrm{N} * \mathrm{R}_{\mathrm{si}}-\left(\mathrm{N}-\mathrm{N}_{\mathrm{p}}\right) * \mathrm{R}_{\mathrm{s}}}\right)
\]
Reference(s)
Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 4, Page: 314.