Pore volume through squared method in tight gas reservoirs

Input(s)

$\mu_{\mathrm{g}, \text { avg: }} $ Average Gas Viscosity $(\mathrm{cP})$

$\mathrm{z}_{\mathrm{avg}}$: Compressibility Factor (dimensionless)

$\mathrm{q}_{\mathrm{i}}$: Initial Gas Rate (MSCF/day)

$\mu_{\mathrm{gi}}$: Initial Gas Viscosity $(\mathrm{cP})$

$\mathrm{c}_{\mathrm{ti}}$: Initial Total Compressibility $(1 / \mathrm{psi})$

$\mathrm{P}_{\mathrm{i}}$: Initial Pressure (psi)

$\mathrm{P}_{\mathrm{wf}}$: Bottom-hole Flowing Pressure (psi)

$\mathrm{D}_{\mathrm{i}}$: Decline Rate $\left(\mathrm{day}^{-1}\right)$

$\mathrm{T}$: Temperature $\left({ }^{\circ} \mathrm{R}\right)$

Output(s)

PV: Pore Volume (dimensionless)

Formula(s)

$$ \mathrm{PV}=\frac{28.27 * \mathrm{~T} * \mu_{\mathrm{g}, \text { avg }} * \mathrm{z}_{\mathrm{avg}}}{\mu_{\mathrm{gi}} * \mathrm{c}_{\mathrm{ti}} *\left(\mathrm{P}_{\mathrm{i}}^{2}-\mathrm{P}_{\mathrm{wf}}^{2}\right)} *\left(\frac{\mathrm{q}_{\mathrm{i}}}{\mathrm{D}_{\mathrm{i}}}\right) $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 252 .