Well Productivity Index Calculator

Calculate PI from well test data or reservoir properties

Calculation Method

Select input method for PI calculation

For calculating rate at target pressure

PI Classification (Oil Wells)

  • Excellent: > 2.0 STB/d/psi
  • Good: 1.0 - 2.0 STB/d/psi
  • Fair: 0.5 - 1.0 STB/d/psi
  • Poor: < 0.5 STB/d/psi

Productivity Index Results

Enter parameters and click Calculate

Formula Reference

Productivity Index from Well Test

J = q / (Pr - Pwf) Where: J = Productivity Index (STB/day/psi) q = Production rate (STB/day) Pr = Static reservoir pressure (psi) Pwf = Flowing bottomhole pressure (psi)

Theoretical PI from Reservoir Properties

J = kh / (141.2 * Bo * mu * (ln(re/rw) + S)) Where: k = Permeability (mD) h = Net pay thickness (ft) Bo = Formation volume factor (RB/STB) mu = Oil viscosity (cp) re = Drainage radius (ft) rw = Wellbore radius (ft) S = Skin factor

Absolute Open Flow (AOF)

AOF = J * Pr This is the theoretical maximum rate at zero bottomhole pressure. Actual maximum rate is limited by practical constraints.