作者：刘易¹, 方方¹, 陈宝², 岳爱忠²

作者单位：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

关键词：岩性密度测井; 闪烁多道谱仪; 符合测量; 稳谱

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。

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

LIU Yi¹, FANG Fang¹, CHEN Bao², YUE Ai-zhong²

1. Institute of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China;
2. Technical Center, China Petroleum Logging Co., Ltd., Xi'an 710077, China

Abstract: A novel stabilization method, which focuses on low-energy spectrum by using the Am-241characteristic 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.

Keywords: litho-density logging; scintillation multi-channel spectrometer; coincidence measurements; spectrum stabilization

2014, 40(1): 5-8  收稿日期: 2013-9-15;收到修改稿日期: 2013-10-28

基金项目: 国家863计划项目(2012AA061800)

作者简介: 刘易(1978-),男,河南信阳市人,博士研究生,主要从事核信号采集与数据处理研究工作。

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