Dimensionless Production Time Formula
Dimensionless Production Time calculates dimensionless production time based on drainage area for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (t_D, r_w, A) 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, t_DA equals 0.003125 dimensionless.
500
0.25
10000
Inputs
t_D
dimensionlessDimensionless Time Based on Wellbore Radius
r_w
mWellbore Radius
A
m^2Drainage Area
Outputs
t_DA
Dimensionless Production Time Based on Drainage Area
t_D
Dimensionless Time Based on Wellbore Radius
r_w
Wellbore Radius
A
Drainage Area
Source and review
reviewedRamey Jr., H. J. Reservoir Engineering Assessment of Geothermal Systems, Department of Petroleum Engineering, Stanford University, Page 5.7.
Source