PetrophysicsRock Properties
Volumetric Photoelectric Absorption Cross Section Formula
Volumetric Photoelectric Absorption Cross Section calculates volumetric photoelectric absorption cross section for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (P_e, rho_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, U equals 7.5 barn/cm^3.
P_ebarn/electron
3
rho_eg/cm^3
2.5
Inputs
P_e
barn/electronEffective Photoelectric Absorption Cross-Section Index
rho_e
g/cm^3Electron Density Index
Outputs
U
barn/cm^3
Volumetric Photoelectric Absorption Cross Section
P_e
barn/electron
Effective Photoelectric Absorption Cross-Section Index
rho_e
g/cm^3
Electron Density Index
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 8, Page 167.
Source