Determination of Lithology from Induced Gamma-Ray Spectroscopy


C. Flaum, G. Pirie,


The Schlumberger Induced Gamma-Ray Spectroscopy Tool (GST*) measures the relative yields of gamma rays resulting from interactions of neutrons with the different elements (isotopes) present in the formation. In particular, in the continuous (or capture-tau) mode, the tool is sensitive to gamma rays resulting from thermal neutron capture by isotopes of silicon, calcium, hydrogen, chlorine, iron, and sulfur.