Damaged/undamaged zone productivity comparison (acidizing)
Input(s)
\(F_{k}\): Permeability Ratio (dimensionless)
\(r_{e}\): Drainage Radius (in.)
\(r_{w}\): Wellbore Radius (in.)
\(r_{s}\) : Damaged Zone Radius (in.)
Output(s)
\(J_{s}\): Damaged or Stimulated Formation Productivity Index (STB/day/psi)
\(J_{o}\) : Undamaged Formation Productivity Index (STB/day/psi)
Formula(s)
\[
\frac{J_{s}}{J_{o}}=\frac{F_{k} \log r_{e} / r_{w}}{\log r_{s} / r_{w}+F_{k} \log r_{e} / r_{s}}
\]
Reference(s)
Williams, B. B., Gidley, J. L., & Schechter, R. S. (1979). Acidizing fundamentals. Henry L. Doherty Memorial Fund of AIME, Society of Petroleum Engineers of AIME, Page: 6.