Epithermal Neutron Flux Distribution Formula
Epithermal Neutron Flux Distribution calculates epithermal neutron flux for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (N_N, D_e, r, L_e) 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, psi_e equals 419.527875 neutrons/cm2/s.
1000000
2.5
20
15
Inputs
N_N
neutrons/sNeutron Source Emission Rate
D_e
cmEpithermal Neutron Diffusion Coefficient
r
cmDistance from Neutron Source
L_e
cmEpithermal Neutron Diffusion Length
Outputs
psi_e
Epithermal Neutron Flux
N_N
Neutron Source Emission Rate
D_e
Epithermal Neutron Diffusion Coefficient
L_e
Epithermal Neutron Diffusion Length
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 2, Page 39.
Source