泵出式密度测井仪长源距岩性MCNP仿真  

MCNP Simulation of Pe Measured by Long-spaced Detector of a Pump-out Density Tool

作　　者：蔡晓波[1] 柏林[1] 吕海泉[1] 程静[1] CAI Xiaobo;BAI Lin;LYU Haiquan;CHENG Jing(The 718th Research Institute of CSIC,Handan,Hebei 056027,China)

机构地区：[1]中国船舶重工集团公司第七一八研究所,河北邯郸056027

出　　处：《测井技术》2018年第3期338-341,共4页Well Logging Technology

基　　金：中国船舶重工集团公司第七一八研究所科技创新基金项目(KJ20150603);国家科技部重点研发计划项目(2016YFF0102700)

摘　　要：泵出式密度测井仪可过钻具被输送至复杂井眼的目的层。与传统密度测井仪相比,由于测井仪外径、探测器伽马射线窗口尺寸等设计的改变,泵出式密度测井仪对地层岩性的灵敏度变差。利用MCNP软件包,建立了泵出式密度测井仪测井模型,模拟了2种不同尺寸的长源距探测器窗口、Al+Fe或Al刻度块条件下的岩性能窗(Lith)、长道低能能窗(LL)、长道高能能窗(LU)计数率及探测器总计数率。适当增大探测器窗口尺寸能提高对岩性的灵敏度及探测效率。模拟结果为优化设计仪器提出了指导性建议。Pump-out density tool can be conveyed through drilling pipes to target layers in a complex hole.Compared with conventional density tools,due to changes in mechanical design of tool＇s outer diameter and size of detector window for gamma-rays easily passing though,the pump-out density tool is less sensitive to formation lithology.A simulation model is set up for logging with the pump-out density tool by using MCNP software package.Count rates of Lith,LL,LU of the long-spaced detector,as well as its total count rate,measured with an Al＋Fe or Al calibration pad,is simulated under the conditions of two different sizes of the detector window.Results show that the lithology sensitivity and detection efficiency can be improved by appropriately increasing size of the detector window.The research results provide guidance for optimal design of the tool.

关 键 词：泵出式测井系统 密度测井仪 模拟 MCNP 岩性 灵敏度 

分 类 号：P631.84[天文地球—地质矿产勘探]