PetrophysicsRock Properties
Porosity from Neutron Flux Response Formula
Porosity from Neutron Flux Response calculates porosity for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (alpha, beta, N) are known and the assumptions behind the cited rock properties 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, phi equals 0.345918 fraction.
alphadimensionless
0.45
betadimensionless
0.08
Ndimensionless
20
Inputs
alpha
dimensionlessNeutron-Porosity Calibration Intercept
beta
dimensionlessNeutron-Porosity Calibration Slope
N
dimensionlessNeutron Tool Response
Outputs
phi
fraction
Porosity
alpha
dimensionless
Neutron-Porosity Calibration Intercept
beta
dimensionless
Neutron-Porosity Calibration Slope
N
dimensionless
Neutron Tool Response
Source and review
reviewedTheory, Measurement, and Interpretation of Well Logs, Bassiouni, Z. (1994)
Bassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 9, Page 174.
source conflict
Source