# Skin factor due to reduced crushed-zone permeability

## Input(s)

\(h_{p}\): Perforation interval (ft)

\(\mathrm{kd}\) : Damage Zone permeability \((\mathrm{mD})\)

kdp: Crushed Zone Permeability \((\mathrm{mD})\)

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

\(r_{d p}\): Crushed Zone radius \((\mathrm{ft})\)

\(r_{p}\): Perforation Radius \((\mathrm{ft})\)

Lp: Depth of Penetration (ft)

N: Total Number of Perforations (number)

## Output(s)

sc: Skin Factor due to Reduced Crushed-Zone Permeability (dimensionless)

## Formula(s)

\[
s c=\left(\frac{k}{k d p}-\frac{k}{k d}\right) * 12 * \frac{h_{p}}{N * L p} * \ln \left(\frac{r_{d p}}{r_{p}}\right)
\]

## Reference(s)

Horizontal Well Technology, Joshi, Page: 504.