地层界面处双侧向测井视电阻率曲线极化角影响因素分析  

Analysis of influencing factors of polarization angle of dual laterolog apparent resistivity curves at stratigraphic interface

作　　者：倪小威 徐观佑 徐思慧 冯加明[1,2] 别康[3] 刘迪仁[1,2] NI Xiaowei;XU Guanyou;XU Sihui;FENG Jiaming;BIE Kang;LIU Diren(Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Yangtze University,Wuhan City,Hubei Province,430100,China;College of Geophysics and Petroleum Resources,Yangtze University,Wuhan City,Hubei Province,430100,China;Research Institute of Exploration and Development,Tarim Oilfield Company,PetroChina,Korla,Xinjiang,841000,China)

机构地区：[1]长江大学油气资源与勘探技术教育部重点实验室,湖北武汉430100 [2]长江大学地球物理与石油资源学院,湖北武汉430100 [3]中国石油塔里木油田公司勘探开发研究院,新疆库尔勒841000

出　　处：《油气地质与采收率》2018年第2期15-19,共5页Petroleum Geology and Recovery Efficiency

基　　金：国家自然科学基金项目"地层条件下富有有机质页岩电磁响应机理与应用基础研究"(U1562109)

摘　　要：常规双侧向测井视电阻率曲线在地层界面处常会出现极化角现象,造成视电阻率曲线畸变并产生"伪薄层"现象,对准确划分地层及准确求取地层真电阻率造成严重影响。基于有限元数值模拟技术,建立双侧向测井数理模型,研究围岩电阻率、地层厚度、储层各向异性、井径以及井斜角对双侧向测井视电阻率曲线极化角形态及幅值的影响程度。研究结果表明:目的层与围岩电阻率对比度越大,双侧向测井视电阻率曲线极化角现象越明显;地层厚度对极化角的影响比较复杂,当地层厚度小于仪器纵向分辨率时,极化角现象消失;储层各向异性会造成极化角幅值发生变化,但对极化角形态的影响较小;随着井径增大,极化角现象趋于消失;井斜角越大,极化角越平缓。双侧向测井视电阻率曲线极化角是多种因素共同作用的结果,在极化角校正工作时应对各影响因素进行综合考虑。Abstract:The apparent resistivity curves of conventional dual laterolog often present polarization angle at the stratigraphic interface,resulting in distortion of the curve form and occurrence of“pseudo thin layer”phenomenon,which seriously af-fects the accurate division of the stratigraphic interface and the accurate calculation of the true resistivity of the strata.Based on the finite element numerical simulation technique,the mathematical model of dual laterolog was established.The effects of surrounding rock resistivity,layer thickness,reservoir anisotropy,well diameter and well inclination on polariza-tion angle and amplitude of dual laterolog apparent resistivity were studied.The results show that the difference between the resistivity of the target layer and the resistivity of the surrounding rock is larger,and the polarization angle of the dual laterolog is more obvious.The effect of layer thickness on the polarization angle is complicated.When the thickness of the strata is thinner than the thickness resolved by instrument measurement,the polarization angle disappears.The anisotropy of the reservoir will cause the amplitude of the polarization angle to change,but the influence on geometry of the polariza-tion angle is small.As the well diameter becomes larger,the polarization angle tends to disappear.The larger the well incli-nation is,the gentler the polarization angle is.The polarization angle of dual laterolog apparent resistivity curve is the result influenced by many factors.In the work of polarization angle correction,all factors should be considered comprehensively

关 键 词：有限元数值模拟 双侧向测井 视电阻率曲线 极化角 影响因素 

分 类 号：P631.821[天文地球—地质矿产勘探]