基于CLYC探测器的可控源中子孔隙度测井数值模拟研究  

Numerical simulation of controllable source neutron porosity logging based on CLYC detector

作　　者：周悦 于华伟[2] 王猛[1] 杜本强 刘志杰 ZHOU Yue;YU Huawei;WANG Meng;DU Benqiang;LIU Zhijie(Well-Tech Department,China Oilfield Services Limited,Sanhe 065201,China;China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中海油田服务股份有限公司油田技术事业部,三河065201 [2]中国石油大学(华东),青岛266580

出　　处：《核技术》2021年第4期70-75,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.4167129);国家重点研发计划(No.2016YFC0302800);中央高校基本科研业务费(No.19CX02004A);国家科技重大专项(No.2017ZX05009001)资助。

摘　　要：利用Cs_(2)LiYCl_(6):Ce(CLYC)探测器替代中子孔隙度测井中的3He中子探测器,已成为石油测井仪器发展的新思路。为探究在中子孔隙度测井中使用新型探测器的可行性,通过蒙特卡罗模拟,研究了CLYC探测器在不同^(6)Li纯度和探测器尺寸下的热中子计数通量,同时与不同内部气压下的^(3)He探测器热中子计数结果进行对比;另外根据仪器使用不同探测器时获取的中子孔隙度响应,验证了CLYC探测器的可替换性。研究表明:新型CLYC探测器在^(6)Li纯度高、探测器尺寸大时热中子计数效率高;相比于^(3)He中子探测器,热中子探测效率较低的CLYC探测器经过源距组合分析优化后,得到的中子近远比响应结果与^(3)He中子探测器近似,能够有效应用于地层孔隙度获取。[Background]Using Cs_(2)LiYCl_(6):Ce(CLYC)instead of 3He detector in neutron porosity logging has become a new idea for the development of logging tools.[Purpose]This study aims to investigate the feasibility of using a new CLYC crystal based detector in neutron porosity logging.[Methods]The Monte Carlo simulation method was employed to study the thermal neutron counting flux of ^(6)Li CLYC detector with different purities and sizes.Thermal neutron counting of this new detector was compared with that of ^(3)He detector under different pressures,the replacement of CLYC detector was verified according to the neutron porosity response of different detectors.[Results]The results show that the new CLYC detector has high thermal neutron counting efficiency when its purity of ^(6)Li and size are large.Compared with 3He detector,the CLYC detector with low thermal neutron detection efficiency has a near/far detector ratio similar to that of ^(3)He detector after optimizing the combination of source diatances which can be effectively applied to obtain formation porosity.[Conclusions]This study provides a theoretical basis for the detector selection and replacement of neutron porosity logging tools in the future.

关 键 词：CLYC探测器 ^(3)He中子探测器 热中子 中子孔隙度测井 蒙特卡罗模拟 

分 类 号：P631.81[天文地球—地质矿产勘探]