岩性密度测井γ能谱低能段稳谱方法研究  

Study on γ low-energy spectrum stabilization of lithology density logging

作　　者：刘易[1] 方方[1] 陈宝 岳爱忠 

机构地区：[1]成都理工大学核技术与自动化工程学院,四川成都610059 [2]中国石油集团测井有限公司技术中心,陕西西安710077

出　　处：《中国测试》2014年第1期5-8,共4页China Measurement & Test

基　　金：国家863计划项目(2012AA061800)

摘　　要：针对岩性密度测井中单一137Cs稳谱在能谱低能段存在非线性谱漂的问题,运用脉冲数字化采集与处理技术,提出一种利用241Am特征峰进行低能段稳谱的方法。采用α符合测量提取淹没在低能段中的241Am特征峰,结合稳谱源137Cs特征峰,调节放大器的数字增益与数字偏置改变双峰道址,使双稳谱源的特征峰道址与能量具有良好的线性关系,进而采取多能窗稳谱方法进行稳谱,最终实现数字双能段双峰稳谱。实验测试表明,该方法可以很好地解决井下温度引起的低能段谱漂难题。A novel stabilization method, which focuses on low-energy spectrum by using the Am241characteristic peaks, is presented. Combination of this method and digital nuclear pulse processing technology is carried out for solving the problem that the low-energy spectrum nonlinear drift caused by single Cs-137 source. Am-241 energy peak can be identified from the low-energy spectrum segment by using α coincidence measurements. Both Am-241 and Cs-137 peaks＇ positions can be revised to make a good channel-energy linear relationship by adjusting the amplifier＇s gain and bias, and the PMT＇s high voltage of multi-channel system. And a digital double peaks stabilization method can be carried out easily. The results of experiment show that it＇s a good solution to the spectral drift problems caused by temperature.

关 键 词：岩性密度测井 闪烁多道谱仪 符合测量 稳谱 

分 类 号：P631.63[天文地球—地质矿产勘探] TN911.7[天文地球—地质学]