导电围岩对井中三维瞬变电磁响应的影响规律研究  

Influence laws of conductive host on borehole 3D transient electromagnetic responses

作　　者：杨怀杰[1] 潘和平[1] 孟庆鑫 郭博[1] 

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074 [2]河北地质大学勘查技术与工程学院,河北石家庄050031

出　　处：《石油物探》2016年第2期288-293,302,共7页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金项目(4107408)资助~~

摘　　要：简要设计地质模型,应用时域有限差分法对模型空间进行非均匀网格剖分,选取磁偶源和不同阶廖氏边界条件,实现了井中均匀全空间和含低阻体的三维瞬变电磁场数值模拟,获得了不同电阻率目标体在导电围岩内电磁场的传播特征以及不同导电围岩对瞬变电磁响应的影响规律。数值模拟结果表明:围岩电阻率越大,电磁总场的极大值出现的时刻越早,随时间衰减越快,且衰减到后期,总场不受围岩电阻率的影响,衰减值几乎相同。The geological model is designed simply and is non-uniform meshed by using the finite difference in time domain,the magnetic dipole source and different-order Liao absorbing boundary are selected,to simulate the 3-D transient electromagnetic field in borehole uniform whole space with a low resistivity body.Meanwhile,the propagation characteristics of the electromagnetic field,which contain different resistivity targets in the surrounding rock,are simulated;and the rules of influence of different conductive surrounding rock on the transient electromagnetic response are analyzed.Numerical simulation results show that when the host is more conductive,appearing time of the total field is earlier and the attenuation is faster along with time.The total field of target body appears to be independent from the conductivity of the host at the later period,and the decay value is almost the same.

关 键 词：瞬变电磁法 有限差分 导电围岩 异常场 廖氏吸收边界 

分 类 号：P631[天文地球—地质矿产勘探]