基于频移的煤岩介质电磁波衰减数值模拟  

The numerical simulation of electromagnetic wave attenuation using the centroid frequency downshift method

作　　者：于师建[1] 

机构地区：[1]山东科技大学矿山灾害预防控制实验室,青岛266590

出　　处：《地球物理学进展》2013年第6期3270-3275,共6页Progress in Geophysics

基　　金：山东省自然科学基金(ZR2011DM014)项目资助

摘　　要：以煤岩介质中存在高电阻率或低电阻率电性地质异常体为实际背景建立物理模型，采用有限差分法对电磁波波动方程进行二维正演数值模拟，并对模拟结果分别计算基于场强的衰减吸收系数和基于频移的衰减吸收系数.数值模拟结果表明，对ρ2/ρ1=1~0.01，利用形心频移计算出的吸收系数变化率为47%，利用场强峰值计算出的吸收系数变化率为36%;对ρ2/ρ1=1~100，利用形心频移计算出的吸收系数变化率为17%，利用场强峰值计算出的吸收系数变化率为13%.无论煤岩中存在低电阻率还是高电阻率地质异常体，利用电磁波信号的频谱漂移参数研究吸收衰减作用均比利用电磁场强度参数研究吸收衰减作用要敏感.This paper takes the abnormal geological objects with high or low resistivity in the coal medium as the background to establish the physical model. 2D forward numerical simulation for electromagnetic wave equation is implemented by the finite-difference scheme. According to the simulative results, the attenuation-absorption coefficient are calculated respectively based on field intensity and frequency downshift parameter. The numerical simulation results indicate： if ρ2/ρ1=1~0.01, the absorption coefficient change rate calculated by center frequency shift is 47%, and the absorption coefficient change rate calculated by field intensity peak value is 36%. If ρ2/ρ1=1~100, the average absorption coefficient change rate calculated by center frequency downshift is 17%, and the average absorption coefficient change rate calculated by field intensity peak value is 13%. Thus it can be seen, either the high or the low resistivity geological objects in coal face, using the electromagnetic wave signal frequency downshift parameter to research the attenuation function is more sensitive than using the electromagnetic field intensity parameter.

关 键 词：电磁波 衰减 频移 数值模拟 

分 类 号：P631[天文地球—地质矿产勘探]