基于数值仿真对介电测井中单线导波进行定量分析  

Quantitative analysis of single wire guided wave in dielectric logging based on numerical simulation

作　　者：黄子轩 王斌[1] 邢兰昌[1] HUANG ZiXuan;WANG Bin;XING LanChang(The College of Control Science and Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)控制科学与控制工程学院,青岛266580

出　　处：《地球物理学进展》2022年第1期192-200,共9页Progress in Geophysics

基　　金：国家自然科学基金(41704124,42174141);中国石油科技创新基金项目(2018D-5007-0214);山东省自然科学基金项目(ZR2019MEE095);中央高校基本科研业务费专项资金项目(20CX05005A);中石油重大科技项目(ZD2019-184-001)联合资助。

摘　　要：在地球物理勘探中,介电测井与井眼雷达是重要的地层评估方法,更好地了解电磁波在目标地层中的传播特性,对于优化勘探工具以及提高反演准确率有着重要作用.本文对介电测井中沿金属钻杆传播的单线导波进行了数值模拟和分析,提出了一种对介电测井中的导波进行定量分析的新方法.采用三维的时域有限差分(FDTD)方法计算了不同饱和度下井眼周围的波场,通过监视沿金属钻杆的总体波场的传播情况,在确定导波的强度和损耗因子后,结合从发射天线发射的总功率,可进一步定量计算出导波的耦合效率.仿真结果表明,侧向波衰减远大于导波,且能量耗尽距离随地层水饱和度增加而降低,导波的耦合效率受地层含水饱和度和频率的双重影响,通过在发射天线附近安装斜坡结构,可以降低耦合到导波的能量,提高工具侧向波辐射能力.In geophysical exploration, dielectric logging and borehole radar are important methods of formation evaluation. Better understanding of the propagation characteristics of electromagnetic wave in the formation plays important role in optimizing design of exploration tools and improving the accuracy of inversion. In this paper, numerical simulation and analysis of guided wave propagating along the metallic drilling collar in dielectric logging are carried out, and a novel method for quantitative analysis of guided wave in dielectric logging is proposed. The 3-D Finite-Difference Time-Domain(FDTD) method is used to calculate the wave field around the borehole at different saturation. By monitoring the propagation of the wave field along the metallic drilling collar, the intensity of the guided wave and loss factor can be determined. Furthermore, by monitoring the total energy emitted by the transmitting antenna, the coupling efficiency of the guided wave can be obtained. The simulation results show that the lateral wave attenuation is much greater than that of the guided wave, and the energy depletion distance decreases with the increase of the formation water saturation. The coupling efficiency of the guided wave is affected by the formation water saturation and frequency. By installing a slope structure near the transmitting antenna, the energy coupled to the guided wave can be reduced, and the tool’s lateral wave radiation ability can be improved.

关 键 词：介电测井 导波 侧向波 时域有限差分(FDTD) 单线波导 

分 类 号：P631[天文地球—地质矿产勘探]