Gas Migration Calculator
Calculate gas migration rate, time to surface, and surface pressure buildup
Well Control Parameters
Enter wellbore and kick information
Gas Migration Factors
- Higher MW = Slower migration
- Larger annulus = Faster migration
- Temperature affects gas expansion
- Deviated wells slow migration
Migration Results
Enter parameters and click Calculate
Typical Migration Rates
| Mud Weight | Migration Rate | Conditions |
|---|---|---|
| 9-10 ppg | 1000-1500 ft/hr | Light mud, large annulus |
| 11-13 ppg | 500-1000 ft/hr | Typical conditions |
| 14-16 ppg | 300-600 ft/hr | Heavy mud |
| 17+ ppg | 200-400 ft/hr | Very heavy mud |
Formula Reference
Gas Migration Velocity (Stokes Law Based)
V_mig = K x (rho_mud - rho_gas) x d^2 / mu
Simplified estimation:
V_mig (ft/hr) ~ 12 x (MW - 0.1) x (Dh - Dp) / MW
Where:
V_mig = Migration velocity (ft/hr)
rho = Density
d = Bubble diameter
mu = Mud viscosity
MW = Mud weight (ppg)
Pressure Buildup Rate
dP/dt = 0.052 x MW x V_mig x (1 - rho_gas/rho_mud)
Or approximately:
dP/dt (psi/hr) ~ 0.05 x MW x V_mig
Time to Surface
t_surface = Kick_Depth / V_mig
Note: Migration rate decreases as gas expands
near surface due to reducing pressure
Gas Expansion
Expansion Factor = P_bottom / P_surface x T_surface / T_bottom
V_surface = V_bottom x Expansion_Factor