Dimensionless Cumulative Production for Radial Flow Constant-Pressure Production Formula
Dimensionless Cumulative Production for Radial Flow Constant-Pressure Production calculates dimensionless cumulative production for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (Q_p, B, phi, c_t, h, r_w, 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_pD equals 476,616.026214 dimensionless.
1000
1.2
0.18
0.00001
40
0.25
3000
2500
Inputs
Q_p
STBCumulative Oil Production
B
RB/STBOil Formation Volume Factor
phi
fractionPorosity
c_t
1/psiTotal Compressibility
h
ftReservoir Thickness
r_w
ftWellbore Radius
p_i
psiInitial Reservoir Pressure
p_wf
psiFlowing Bottomhole Pressure
Outputs
Q_pD
Dimensionless Cumulative Production
Q_p
Cumulative Oil Production
B
Oil Formation Volume Factor
phi
Porosity
c_t
Total Compressibility
h
Reservoir Thickness
r_w
Wellbore Radius
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