Dimensionless time for semi-steady state flow in coal bed methane reservoirs
Input(s)
\(k_{g}\): Effective Gas Compressibility (1/psi)
\(\mathrm{t}\): Time (h)
\(\emptyset\): Porosity (fraction)
\(\mu_{g i}\): Gas Viscosity at Initial Pressure \((\mathrm{cP})\)
\(c_{t i}\): Total Compressibility at Initial Pressure \((1 / \mathrm{psi})\)
A: Drainage Area \(\left(\mathrm{ft}^{2}\right)\)
Output(s)
\(t_{D A}\): Dimensionless Time (dimensionless)
Formula(s)
\[
\mathrm{t}_{\mathrm{DA}}=\frac{0.0002637 * \mathrm{k}_{\mathrm{g}} * \mathrm{t}}{\emptyset * \mu_{\mathrm{gi}} * \mathrm{c}_{\mathrm{ti}} * \mathrm{~A}}
\]
Reference(s)
Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 221 .