Numerical Simulation on Detector Response in Formation Element Logging

LaBr₃ and BGO scintillators are often used for γ spectra detection to determine element and mineral content in formation element logging, and the crystal scintillator counting efficiency and energy resolution are critical factors for the quality of measuring spectrum and computational accuracy of element content. In this paper, the detector spectrum response characteristics of LaBr₃ and BGO scintillators were compared. The γ response spectra of the two kinds of scintillators were simulated under the formation condition with different kinds of elements and diverse contents by Monte Carlo method, and then the element content was calculated by least square processing method. The calculated results based on different scintillators have less diverse when the formation has the lesser kinds of elements. However, when the formation has more kinds of elements, the γ ray peaks of different elements in the spectrum overlap and influence each other obviously. The more accurate results can be derived by LaBr₃ detector than those by BGO detector. It reflects the element measurement advantage of high resolution scintillator in the formation with complex lithology.