PetrophysicsRock Properties
Larionov Tertiary-Rock Shale Volume from Gamma Ray Index Formula
Larionov Tertiary-Rock Shale Volume from Gamma Ray Index calculates shale volume for tertiary rocks for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (I_GR) 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, V_sh equals 0.148527 fraction.
I_GRfraction
0.4
Inputs
I_GR
fractionGamma Ray Index
Outputs
V_sh
fraction
Shale Volume for Tertiary Rocks
I_GR
fraction
Gamma Ray Index
Source and review
reviewedLarionov, V.V. 1969. Borehole Radiometry; Aptian Technical gamma-ray shale-volume crossplot references.
Source