Production EngineeringInflow Performance
Straight-Line IPR Rate from Test Point Formula
Straight-Line IPR Rate from Test Point calculates predicted oil flow rate for inflow performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (q_test, P_r, P_wf_test, P_wf) are known and the assumptions behind the cited inflow performance relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, q_o equals 1,000 STB/day.
q_testSTB/day
500
P_rpsi
3000
P_wf_testpsi
2500
P_wfpsi
2000
Inputs
q_test
STB/dayStabilized Oil Test Rate
P_r
psiAverage Reservoir Pressure
P_wf_test
psiFlowing Bottom-Hole Pressure at Test Rate
P_wf
psiTarget Flowing Bottom-Hole Pressure
Outputs
q_o
STB/day
Predicted Oil Flow Rate
J
STB/day/psi
Productivity Index from Test Point
Source and review
reviewedProductivity index and straight-line IPR from test rate and pressure drawdown.
Source