Average permeability in radial systems
Input(s)
\(k_{a}\): Permeability between \(r_{w}\) and \(r_{a}(\mathrm{mD})\)
\(k_{e}\): Permeability between \(r_{e}\) and \(r_{a}(\mathrm{mD})\)
\(r_{e}\): Drainage radius (ft)
\(r_{w}\): Well bore radius (ft)
\(r_{a}\): Radius lesser than \(r_{e}(\mathrm{ft})\)
Output(s)
\(k_{\text {avg }}\): Average Permeability in Radial Systems Series (mD)
Formula(s)
\[
k_{a v g}=\frac{k_{a} * k_{e} * \ln \left(\frac{r_{e}}{r_{w}}\right)}{k_{a} * \ln \left(\frac{r_{e}}{r_{a}}\right)+k_{e} * \ln \left(\frac{r_{a}}{r_{w}}\right)}
\]
Reference(s)
Applied Reservoir Engineering Vol. 1, Smith, Tracy & Farrar, Equation 7-7.