自然γ能谱型测井仪的蒙卡建立

Development of a Gamma Spectrometer by Monka for a Logging Device

针对当前自然γ能谱型测井研究较少,可利用蒙特卡罗方法对自然γ能谱型测井进行更深入的研究。根据实际自然γ能谱型测井仪的几何结构以及实测获得的能量刻度和分辨率系数建立自然γ能谱型测井仪的数值模型。通过将数值模型获得的能谱图与实测能谱图进行比较,以验证数值模型的准确性。选取模拟能谱与标准源(137Cs、60Co)的实测能谱中相同的特征峰半高宽和特征峰峰面积进行比较,其误差<5%,验证了模拟中需要的分辨率系数的准确性。并在相同的铀含量环境中,选取模拟能谱与实测能谱中的铀、钍、钾特征峰能量段以及总能量段进行比较,其误差<3%,验证了利用蒙特卡罗方法建立的数值模型的准确性。该研究结果可为自然γ能谱型测井的后续研究提供理论技术依据。

In view of the fact that there are few studies on natural gamma spectrum logging,the Monte Carlo method can be used to conduct more in-depth research on natural gamma spectrum logging.The numerical model of the natural gamma spectrum logging tool is established according to the geometric structure of the actual natural gamma spectrum logging tool and the measured energy scale and resolution coefficient.The accuracy of the numerical model is verified by comparing the energy spectrum obtained from the numerical model with the measured energy spectrum.Select the simulated energy spectrum and the measured energy spectrum of the standard source(137Cs,60Co)to compare the same characteristic peak half maximum width and characteristic peak area,and the error is less than 5%,which verifies the accuracy of the resolution coefficient required in the simulation.And in the same uranium content environment,the simulated energy spectrum was selected to compare with the energy range of the characteristic peaks of uranium,thorium,potassium and the total energy range in the measured energy spectrum,and the error was less than 3%,which verified that the Monte Carlo method established accuracy of numerical models.The research results provide a theoretical and technical basis for the follow-up research on naturalγ-spectrum logging.