PetrophysicsRock Properties
Photoelectric Absorption Cross Sectional Area Formula
Photoelectric Absorption Cross Sectional Area calculates photoelectric absorption cross sectional area for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (Z, E_gamma) 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, alpha_pe equals 0.062084 barn/electron.
Zdimensionless
13
E_gammakeV
100
Inputs
Z
dimensionlessAtomic Number
E_gamma
keVGamma Ray Energy
Outputs
alpha_pe
barn/electron
Photoelectric Absorption Cross Sectional Area
Z
dimensionless
Atomic Number
E_gamma
keV
Gamma Ray Energy
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 2, Page 36.
Source