Dimensionless Rate for Radial Flow Constant-Pressure Production Formula
Dimensionless Rate for Radial Flow Constant-Pressure Production calculates dimensionless rate for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (q, B, mu, k, h, p_i, p_wf) are known and the assumptions behind the cited pressure transient analysis 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_D equals 0.169492 dimensionless.
500
1.2
2
50
40
3000
2500
Inputs
q
STB/dayOil Flow Rate
B
RB/STBOil Formation Volume Factor
mu
cPOil Viscosity
k
mDPermeability
h
ftReservoir Thickness
p_i
psiInitial Reservoir Pressure
p_wf
psiFlowing Bottomhole Pressure
Outputs
q_D
Dimensionless Rate
q
Oil Flow Rate
B
Oil Formation Volume Factor
mu
Oil Viscosity
k
Permeability
h
Reservoir Thickness
p_i
Initial Reservoir Pressure
p_wf
Flowing Bottomhole Pressure
Source and review
reviewedLee, J., Rollins, J. B., and Spivey, J. P. Pressure Transient Testing, SPE Textbook Series Vol. 9, Page 9.
Source