Oil in place for undersaturated oil reservoirs without fluid injection

Input(s)

$\mathrm{N}_{\mathrm{p}}$: Produced Oil (STB)

$B_{\mathrm{o}}$: Oil Formation Volume Factor (rb/STB)

$\mathrm{B}_{\mathrm{oi}}$: Initial Oil Formation Volume Factor (rb/STB)

$\mathrm{S}_{\mathrm{wi}}$: Initial Water Saturation (fraction)

$\mathrm{c}_{\mathrm{w}}$: Water Compressibility (1/psi)

$\mathrm{c}_{\mathrm{f}}$: Formation Compressibility $(1 / \mathrm{psi})$

$\Delta \mathrm{P}$: Pressure Differential (psi)

Output(s)

$\mathrm{N}$: Oil in Place $(\mathrm{STB})$

Formula(s)

$$ \mathrm{N}=\frac{\mathrm{N}_{\mathrm{p}} * \mathrm{~B}_{\mathrm{o}}}{\mathrm{B}_{\mathrm{o}}-\mathrm{B}_{\mathrm{oi}}+\mathrm{B}_{\mathrm{oi}} *\left(\frac{\mathrm{S}_{\mathrm{wi}} * \mathrm{c}_{\mathrm{w}}+\mathrm{c}_{\mathrm{f}}}{1-\mathrm{S}_{\mathrm{wi}}}\right) * \Delta \mathrm{P}} $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 5, Page: 333 .