Nuclear well logging tool with at least one gamma-ray scintillation detector employing a thallium-based scintillator material

摘要

A subsurface logging tool that is deployable in a wellbore that traverses a formation includes a gamma-ray scintillation detector with a thallium-based scintillator material. The scintillator material is suitable for high-temperature downhole environments (i.e., above 70° C.). As such, the scintillator material improves the performance of oilfield measurement(s) at temperatures above 70° C. and at least up to 175° C., when compared with the use of the other materials. The scintillator material may have an effective atomic number of at least sixty. The scintillator material may have the chemical formula Tl₂LiY_1-xCe_xCl₆, where x is 0 to 1. Lithium (Li) may be partially or completely replaced by another alkali metal or by indium (In). Yttrium (Y) is partially or completely replaced by another rare earth element. Chlorine (Cl) is partially or completely replaced by another halide.