Reservoir EngineeringPressure Transient Analysis
Permeability from Pressure Transient Semilog Slope Formula
Permeability from Pressure Transient Semilog Slope calculates effective permeability to produced phase for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (q, B, mu, m, h) 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, k equals 48.78 mD.
qSTB/day
500
BRB/STB
1.2
mucP
2
mpsi/cycle
80
hft
50
Inputs
q
STB/dayOil Flow Rate
B
RB/STBOil Formation Volume Factor
mu
cPOil Viscosity
m
psi/cycleSemilog Straight-Line Slope
h
ftNet Pay Thickness
Outputs
k
mD
Effective Permeability to Produced Phase
q
STB/day
Oil Flow Rate
B
RB/STB
Oil Formation Volume Factor
mu
cP
Oil Viscosity
m
psi/cycle
Semilog Straight-Line Slope
h
ft
Net Pay Thickness
Source and review
reviewedAAPG Wiki, Pressure transient testing, semilog permeability equation after W. John Lee.
Source