各向异性介质井孔瞬变电磁视电阻率和视倾角计算  

Calculation of borehole transient electromagnetic apparent resistivity and dip in anisotropic medium

作　　者：赵宁 张赵墺基 姜黎明 肖占山 胡海涛 ZHAO Ning;ZHANG Zhaoaoji;JIANG Liming;XIAO Zhanshan;HU Haitao(School of Physics&Electronic Information Engineering,Henan Polytechnic University,Jiaozuo 454000,Henan,China;Well Logging Key Laboratory,China National Petroleum Corporation,Xi’an 710077,Shaanxi,China)

机构地区：[1]河南理工大学物理与电子信息学院,河南焦作454000 [2]中国石油集团测井有限公司,陕西西安710077

出　　处：《河南理工大学学报(自然科学版)》2025年第2期81-89,共9页Journal of Henan Polytechnic University(Natural Science)

基　　金：国家自然科学基金资助项目(42474115);河南省自然科学基金资助项目(242300421364);河南省高校基本科研业务费专项资金资助项目(NSFRF230428);河南理工大学科技创新团队项目(XJ2021000701);河南理工大学“双一流”学科创建项目(GCCYJ202407)。

摘　　要：瞬变电磁远探测在探测深度和分辨率方面,填补了常规测井和地震勘探的地质评价尺度空白带。但是,目前建立在各向同性介质基础上的理论模型,与我国大多数地区油气田客观存在的开发环境,即非均质、各向异性地层的事实不符。目的考虑到地下介质的复杂性和非均质性等特点,针对各向异性地层中的井孔瞬变电磁法研究具有重要意义。方法基于井孔瞬变电磁理论,通过研究三轴感应数据,采用解析计算方式推导各向异性地层井孔瞬变电磁视电阻率、视倾角关系表达式,通过建立水平和倾斜各向异性地层模型对视电阻率和视倾角进行计算与分析。结果结果表明:对于均匀各向同性介质模型,视电阻率可以较好反映地层阻值变化情况,视倾角与模型地层倾角基本吻合;对于垂直对称轴横向各向同性(transversely isotropic media with a vertical symmetry axis,VTI)的各向异性介质模型,视电阻率与视倾角能够较好反映各向异性地层的水平、垂直电阻率和倾角。结论井孔瞬变电磁响应能够快速计算出各向异性地层中视电阻率和视倾角,有助于快速分析观测装置附近电性结构,对各向异性介质井孔瞬变电磁领域的快速发展具有重要意义。In the fields of resource exploration and development,as well as geological disaster prevention and control,the electromagnetic method of borehole is an effective tool for monitoring subsurface fluid dis-tribution,particularly in evaluating the effectiveness of hydraulic fracturing and grouting for water control.Transient electromagnetic remote detection fills the gap in geological assessment scale of conventional log-ging and seismic exploration in terms of detection depth and resolution.However,the current theoretical models based on isotropic media do not fully correspond to the actual development environment of most oil and gas fields in China,which is the fact of heterogeneous and anisotropic formations.Objectives Consider-ing the complexity and heterogeneity of subsurface media,it is of great significance to study borehole tran-sient electromagnetic method in anisotropic formations.Methods Based on borehole transient electromag-netic theory,the relationship between apparent resistivity and apparent dip angle of anisotropic formation borehole is derived through analytical calculation by studying the three component induction data.Results The results indicate that for isotropic media models,the apparent resistivity and apparent dip angle effec-tively can better reflect the formation resistivity and dip angle within the model.For anisotropic models with transversely isotropic media with a vertical symmetry axis(VTI),the apparent resistivity and apparent dip angle similarly can better reflect the horizontal and vertical resistivity and dip angle of the anisotropic for-mations.Conclusions The results enable rapid calculation of apparent resistivity and apparent dip angle in anisotropic formations,facilitating quick analysis of the electrical structure near the observation device and significantly contributing to the rapid development of borehole transient electromagnetics in anisotropic media.

关 键 词：井孔瞬变电磁法 各向异性 视电阻率 视倾角 

分 类 号：P631[天文地球—地质矿产勘探]