摘要
频率域井地电磁方法是指在井中供以交流电在地面接收电磁响应的一类电磁勘探方法。本文提出一种层状介质模型的井地电磁响应的推导方法,首先推导地表水平电偶极源在层状介质中垂向电磁场的响应公式,再沿垂直导线方向进行积分,根据互换原理得到地下垂直有限长导线电流源的井地电磁响应的解析公式。对于地下层状介质中任意深度和长度的垂直有限长线电流源的井地电磁响算法应该均可计算,在保证计算精度的前提下,具有计算量小、计算速度快的优点。论文给出采用不同方法计算均匀半空间模型的井地电磁响应的模拟结果的验证及计算精度和计算速度的对比,算例结果表明利用互换原理推导的井地电磁响应公式正确。
Borehole-surface electromagnetic（BSEM） method is an electromagnetic exploration wayto measure the EM response on the ground excited by an alternating current source in borehole.In this paper,it puts forward an analysis way for BSEM response through a layered medium.At first,the analytical formula of the electromagnetic responses are obtained by integrating the time-harmonic response of the horizontal electric dipole（VED） whose analysis formula is derived by using coefficient recursion relations and from the tangential components continuity;and then the algorithm can calculate the BSEM responses of vertical finite length linear current source with arbitrary length or depth,and the formula is brief and fast.This paper proposes different methods to calculatethe simulation resultsofthe borehole-surface electromagnetic responses in homogeneous half-space model and makes comparison of the calculating accuracy and speed;it is proved that the BSEM response formula derived by the principle of reciprocity is correct.
出处
《工程地球物理学报》
2010年第5期579-583,共5页
Chinese Journal of Engineering Geophysics
关键词
互换原理
井地电磁
一维正演
频率域
principle of reciprocity
borehole-surface electromagnetic
one-dimension forward
frequency domain
