Skin Factor Analysis Calculator

Analyze well damage, flow efficiency, and stimulation potential

Well Test Parameters

Enter pressure test and reservoir data

Total system compressibility

Skin Factor Interpretation

  • S < 0: Stimulated (acidized/fractured)
  • S = 0: Undamaged (ideal)
  • S = 1-5: Slight damage
  • S = 5-10: Moderate damage
  • S > 10: Severe damage

Skin Factor Results

Enter parameters and click Calculate

Formula Reference

Skin Factor Calculation

S = (kh / 141.2qBmu) * (Pr - Pwf) - ln(re/rw) + 0.75 Rearranged from Darcy's radial flow equation: q = kh(Pr - Pwf) / (141.2 * Bo * mu * (ln(re/rw) + S - 0.75))

Pressure Drop Due to Skin

Delta_P_skin = (141.2 * q * Bo * mu * S) / (k * h) This represents the additional pressure drop caused by near-wellbore damage.

Flow Efficiency

FE = J_actual / J_ideal = (Pr - Pwf - Delta_P_skin) / (Pr - Pwf) FE = ln(re/rw) / (ln(re/rw) + S) Where: FE = 1.0 means no damage (S = 0) FE < 1.0 means damaged well (positive skin) FE > 1.0 means stimulated well (negative skin)

Effective Wellbore Radius

r_eff = rw * exp(-S) For stimulated wells (S < 0), r_eff > rw For damaged wells (S > 0), r_eff < rw