PetrophysicsRock Properties
Pair Production Gamma Ray Interactions Formula
Pair Production Gamma Ray Interactions calculates excess energy available after pair production for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (E_c, 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, E_e equals 1.478 MeV.
E_cMeV
2.5
EMeV
1.022
Inputs
E_c
MeVIncident Gamma Ray Energy
E
MeVPair Production Threshold Energy
Outputs
E_e
MeV
Excess Energy Available After Pair Production
E_c
MeV
Incident Gamma Ray Energy
E
MeV
Pair Production Threshold Energy
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 2, Page 33.
Source