Initial gas in place for water-drive gas reservoirs
Input(s)
\(\mathrm{G}_{\mathrm{p}}\): Cumulative Gas Production at Depletion Pressure (SCF)
\(\mathrm{B}_{\mathrm{g}}\): Gas Formation Volume Factor at Depletion Pressure (bbl/SCF)
\(\mathrm{W}_{\mathrm{e}}\): Cumulative Water Influx (bbl)
\(\mathrm{W}_{\mathrm{p}}\): Cumulative Water Production at Depletion Pressure (STB)
\(\mathrm{B}_{\mathrm{w}}\): Water Formation Volume Factor (bbl/STB)
\(\mathrm{B}_{\mathrm{gi}}\): Initial Gas Formation Volume Factor (bbl/SCF)
Output(s)
G: Gas Initially in Place (MSCF)
Formula(s)
\[
\mathrm{G}=\frac{\mathrm{G}_{\mathrm{p}} * \mathrm{~B}_{\mathrm{g}}-\left(\mathrm{W}_{\mathrm{e}}-\mathrm{W}_{\mathrm{p}} * \mathrm{~B}_{\mathrm{w}}\right)}{\mathrm{B}_{\mathrm{g}}-\mathrm{B}_{\mathrm{gi}}}
\]
Reference(s)
Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 207.