Production EngineeringInflow Performance
Vogel Inflow Performance Relationship Formula
The Vogel IPR estimates oil well inflow rate under two-phase flow conditions using flowing bottomhole pressure and average reservoir pressure.
How engineers use this formula
Use it for solution-gas-drive oil wells where the inflow curve is nonlinear below bubblepoint pressure.
Assumptions
- The well behavior matches the empirical Vogel oil IPR relationship.
- Reservoir pressure and bottomhole flowing pressure are representative.
- The equation is applied within its intended oil-well inflow context.
Limitations
- Not a gas deliverability equation.
- Not a substitute for a calibrated nodal-analysis model when detailed system behavior is needed.
Common mistakes
- Applying Vogel directly to dry-gas wells.
- Using wellhead pressure instead of bottomhole flowing pressure.
- Forgetting that pressure ratio terms should be dimensionless.
Default example
Using the default inputs, q_o equals 700 STB/day.
q_maxSTB/day
1000
P_wfpsi
1500
P_rpsi
3000
Inputs
q_max
STB/dayMaximum Oil Rate at Zero Flowing Bottom-Hole Pressure
P_wf
psiBottom-Hole Flowing Pressure
P_r
psiAverage Reservoir Pressure
Outputs
q_o
STB/day
Oil Flow Rate
q_max
STB/day
Maximum Oil Rate at Zero Flowing Bottom-Hole Pressure
x
dimensionless
Vogel Pressure Ratio
P_wf
psi
Bottom-Hole Flowing Pressure
P_r
psi
Average Reservoir Pressure
Source and review
reviewedVogel, J.V. 1968. Inflow Performance Relationships for Solution-Gas Drive Wells.
Source