Total skin in partially depleted wells for a buildup test


\(r_{e w}\): Dimensionless Parameter in terms of Perforated Length and Wellbore Radius (dimensionless)

\(\emptyset\) : Porosity (fraction)

\(\mu\) : Viscosity \((\mathrm{cP})\)

\(c_{t}\): Total Compressibility \((1 / \mathrm{psi})\)

k: Permeability \((\mathrm{mD})\)

\(p_{s}\): Shut-in Pressure at any Shut-in Time (psi)

\(p_{w}\) : Well Flowing Pressure at the Instant of Shut-in (psi)

\(\Delta t\): Shut-in Time (day)

\(\mathrm{m}\) : Slope of Cartesian Pressure Build-up Plot (psi/cycle)


S: Skin (dimensionless)


\[ S=34.7 * r_{e w} *\left(\left(\left(\emptyset * \mu * \frac{c_{t}}{k}\right)\right)^{0.5}\right) *\left(\left(\frac{p_{s}-p_{w}}{m}\right)+\left(\frac{1}{(\Delta t)^{0.5}}\right)\right)-1 \]


Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1, Page: 81 .

An unhandled error has occurred. Reload 🗙