横向各向同性介质中用于井-地传输的电磁波的准确快速计算  

Accurate and fast simulation of electromagnetic waves for well-to-ground transmission in transverse isotropic media

作　　者：梁朋飞 真齐辉 云喆 付长民[1,2,3] 王若 底青云[1,2,3] LIANG PengFei;ZHEN QiHui;YUN Zhe;FU ChangMin;WANG Ruo;DI QingYun(CAS Engineering Laboratory for Deep Resources Equipment and Technology,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院深地资源装备技术工程实验室,中国科学院地质与地球物理研究所,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球物理学报》2023年第1期122-130,共9页Chinese Journal of Geophysics

基　　金：中国科学院A类战略性先导科技专项(XDA14050102,XDA14020101)资助.

摘　　要：井-地电磁传输系统是解决随钻测量(MWD)中观测的各种参数(井斜、井周速度、电导率、孔隙度)和井场的指令在井-地间实时传输问题的新思路,应用潜力巨大,受到了相关研究人员的广泛关注.本文提出了一种在横向各向同性介质中精确、快速地模拟井-地电磁传输中电磁波传播、分布的方法,为井-地电磁传输系统的设计、开发提供必要的支持.该方法利用矩量法将沿钻杆分布的电流离散,并基于钻杆上电流分布与格林函数的乘积的积分对散射电磁场进行计算,经过与基于有限元法的COMSOL软件模拟结果对比,验证了该方法的有效性.同时还讨论了钻杆电导率、工作频率、横向各向同性异常层、目标层电导率等参数对电磁场的影响.研究发现高电导率的钻杆能提高电磁波的辐射能力,钻杆上电流分布、地面接收的电压信号对地层模型横向电导率的变化较电导率垂向分量变化更敏感.Electromagnetic telemetry systems have attracted considerable attention owing to their increasing applications in measurement-while-drilling.In simulations,the long,thin drill string of the telemetry system is simplified as an antenna penetrating a layered medium,and,typically,there is a source segment near the drill bit to induce excitations.In this study,a method to accurately and efficiently simulate an electromagnetic telemetry system within a transversely isotropic medium was proposed.The method of moments was utilized to discretize the current distributed along the drill string,and then we estimated the current distribution.Subsequently,the scattering field was analytically simulated through the integration of the product of the solved current distribution and Green′s function.The proposed method does not require complex numerical simulations for the integration and is verified through comparisons with that from the COMSOL commercial software,which is based on the finite element method.The effects of the conductivity of the drill string,operation frequency,transversely isotropic anomaly,target anomaly layer were also estimated using different models with the transversely isotropic medium.It reveals that the high conductivity of the drill string could improve the radiation efficiency of the source.The current distribution along the drill string and the voltage signals received on the ground are more sensitive to variations of transverse components of conductivity than its vertical components.

关 键 词：矩量法 积分方程 井-地传输 电磁法 快速模拟 

分 类 号：P631[天文地球—地质矿产勘探]