Gas drive index in gas reservoirs

Input(s)

$G$: Gas Initially in Place $(\mathrm{SCF})$

$G_{p}$: Cumulative Gas Production (SCF)

$B_{g i}$: Initial Gas Formation Volume Factor $\left(\mathrm{ft}^{3} / \mathrm{SCF}\right)$

$B_{g}$: Gas Formation Volume Factor $\left(\mathrm{ft}^{3} / \mathrm{SCF}\right)$

Output(s)

GDI: Gas (dimensionless)

Formula(s)

$$ G D I=\left(\frac{G}{G_{p}}\right) *\left(1-\frac{B_{g i}}{B_{g}}\right) $$

Reference(s)

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