Dimensionless Wellbore Storage Coefficient of Radial Flow – Constant-Rate Production Formula
Dimensionless Wellbore Storage Coefficient of Radial Flow – Constant-Rate Production calculates dimensionless wellbore storage coefficient for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (C, phi, c_t, h, r_w) 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, C_d equals 1,654.814815 dimensionless.
0.01
0.2
6e-6
50
0.3
Inputs
C
STB/psiWellbore Storage Coefficient
phi
fractionPorosity
c_t
1/psiTotal Compressibility
h
ftReservoir Thickness
r_w
ftWellbore Radius
Outputs
C_d
Dimensionless Wellbore Storage Coefficient
C
Wellbore Storage Coefficient (rearranged)
phi
Porosity (rearranged)
c_t
Total Compressibility (rearranged)
h
Reservoir Thickness (rearranged)
r_w
Wellbore Radius (rearranged)
Source and review
reviewedLee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of Petroleum Engineers, Page: 8.
Source