Relation between concentration of K, Th, or U and recorded total gamma ray signal

Input(s)

$C_{T h}:$ Thorium Concentration (ppm)

$C_{U}$: Uranium Concentration $(\mathrm{ppm})$

$C_{K}$: Potassium Concentration (wt \%)

Output(s)

$\gamma$: Total Gamma Ray (API units)

Formula(s)

$$ \gamma=4 * C_{T h}+8 * C_{U}+C_{K} $$

Reference(s)

Bassiouni, Z., 1994, Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4. Chapter 7, Page: 152.