Time to reach the semi-steady state for a gas well in a circular or square drainage area (1)

Input(s)

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

$\emptyset$: Porosity (fraction)

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

A: Drainage Area $\left(\mathrm{ft}^{2}\right)$

$\mathrm{k}$: Effective Gas Permeability $(\mathrm{mD})$

Output(s)

$\mathrm{t}_{\mathrm{pss}}$: Time (h)

Formula(s)

$$ \mathrm{t}_{\mathrm{pss}}=\frac{15.8 * \emptyset * \mu_{\mathrm{gi}} * \mathrm{c}_{\mathrm{ti}} * \mathrm{~A}}{\mathrm{k}} $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 194.