Reservoir Pressure Drawdown Calculator

Calculate flowing bottomhole pressure and drawdown for production optimization

Reservoir Parameters

Enter reservoir and well data

Typical: 0.25-0.5 ft

Negative = stimulated

Drawdown Considerations

  • Excessive drawdown may cause formation damage
  • Stay above bubble point pressure
  • Consider sand production limits

Pressure Drawdown Results

Enter parameters and click Calculate

Formula Reference

Darcy's Radial Flow Equation (Steady-State)

q = (kh(Pr - Pwf)) / (141.2 * Bo * mu * (ln(re/rw) + S)) Where: q = Production rate (STB/day) k = Permeability (mD) h = Net pay thickness (ft) Pr = Static reservoir pressure (psi) Pwf = Flowing bottomhole pressure (psi) Bo = Formation volume factor (RB/STB) mu = Oil viscosity (cp) re = Drainage radius (ft) rw = Wellbore radius (ft) S = Skin factor (dimensionless)

Productivity Index

J = q / (Pr - Pwf) = kh / (141.2 * Bo * mu * (ln(re/rw) + S)) Units: STB/day/psi

Pressure Drawdown

Drawdown = Pr - Pwf Drawdown Ratio = (Pr - Pwf) / Pr * 100% Guidelines: - Keep drawdown < 10-15% of Pr for unconsolidated sands - Stay above bubble point to prevent gas breakout - Higher drawdown = higher production but increased risk