# Skin factor

## Input(s)

\(k_{s}\): Permeability of damaged zone \((\mathrm{mD})\)

\(r_{s}\): Radius of damaged zone \((\mathrm{ft})\)

\(r_{w}\) : Radius of wellbore (ft)

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

## Output(s)

s: Skin (dimensionless)

## Formula(s)

\[
s=\left(\frac{k}{k_{s}}-1\right) * \ln \left(\frac{r_{s}}{r_{w}}\right)
\]

## Reference(s)

Fundamental Principles of Reservoir Engineering, Towler, Page: 62.