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Vogel Inflow Performance Relationship Calculator

qo=qmax[10.2(PwfPr)0.8(PwfPr)2]q_o = q_{max}\left[1 - 0.2\left(\frac{P_{wf}}{P_r}\right) - 0.8\left(\frac{P_{wf}}{P_r}\right)^2\right]

Enter maximum oil rate, flowing bottomhole pressure, and reservoir pressure. The calculator returns the predicted oil rate.

Tabular solver

Inputs

Defaults provide a quick field-unit example for the equation.

3 variables

Your input values and calculation stay in this browser.

Engineering reference summary

Calculation context and source notes

The Vogel IPR estimates oil well inflow rate under two-phase flow conditions using flowing bottomhole pressure and average reservoir pressure.

Use it for solution-gas-drive oil wells where the inflow curve is nonlinear below bubblepoint pressure. Calibrate maximum rate or a test-point form with representative stabilized pressure and rate data whenever available.

Solves for

q_o (STB/day)

Related source-backed guides

Formula reference

Formula, variables, and default calculation

qo=qmax[10.2(PwfPr)0.8(PwfPr)2]q_o = q_{max}\left[1 - 0.2\left(\frac{P_{wf}}{P_r}\right) - 0.8\left(\frac{P_{wf}}{P_r}\right)^2\right]

Reproducible default result

With the default values shown below, the calculation returns q_o = 700 STB/day. Defaults demonstrate the implementation; they are not recommended field values.

q_maxSTB/day

1000

P_wfpsi

1500

P_rpsi

3000

Input definitions

q_max

STB/day

Maximum Oil Rate at Zero Flowing Bottom-Hole Pressure

P_wf

psi

Bottom-Hole Flowing Pressure

P_r

psi

Average Reservoir Pressure

Output definitions

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

Engineering use, assumptions, and limits

Use it for solution-gas-drive oil wells where the inflow curve is nonlinear below bubblepoint pressure. Calibrate maximum rate or a test-point form with representative stabilized pressure and rate data whenever available.

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.

Source and record status

Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.

reviewedguidance published

Vogel, J.V. 1968. Inflow Performance Relationships for Solution-Gas Drive Wells.

Open source reference

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