Dimensionless Pressure – Kamal and Brigham Formula
Dimensionless Pressure – Kamal and Brigham calculates dimensionless pressure for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (Q, k, h, B, mu, dP) 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, P_d equals 236.071766 dimensionless.
500
100
50
1.2
0.25
1000
Inputs
Q
STB/dayFlow Rate
k
mDAverage Permeability
h
ftReservoir Thickness
B
bbl/STBFormation Volume Factor
mu
cPViscosity
dP
psiPressure Difference
Outputs
P_d
Dimensionless Pressure
Q
Flow Rate (rearranged)
k
Average Permeability (rearranged)
h
Reservoir Thickness (rearranged)
B
Formation Volume Factor (rearranged)
mu
Viscosity (rearranged)
dP
Pressure Difference (rearranged)
Source and review
reviewedAhmed, T., McKinney, P.D. (2005). Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1, Page: 125.
Source