Water-drive index for gas reservoirs

Input(s)

$\mathrm{W}_{\mathrm{e}}$: Cumulative Water Influx (bbl)

$\mathrm{W}_{\mathrm{p}}$: Cumulative Water Production $(\mathrm{bbl})$

$\mathrm{B}_{\mathrm{w}}$: Water Formation Volume Factor (rb/STB)

$\mathrm{G}_{\mathrm{p}}$: Cumulative Gas Production at Depletion Pressure (MSCF)

$\mathrm{B}_{\mathrm{g}}$: Gas Formation Volume Factor at Depletion Pressure (bbl/SCF)

Output(s)

WDI: Water Drive Index (dimensionless)

Formula(s)

$$ \mathrm{WDI}=\frac{\mathrm{W}_{\mathrm{e}}-\mathrm{W}_{\mathrm{p}} * \mathrm{~B}_{\mathrm{w}}}{\mathrm{G}_{\mathrm{p}} * \mathrm{~B}_{\mathrm{g}}} $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 211.