电磁测深数据地形影响的快速校正

地形起伏会对电磁法的数据产生一定影响,尤其会影响浅部地层电性结果的准确性.本文通过对地形影响基本规律、经典比值校正原理的分析,认为可以用实测标准电阻率替代数值模拟中均匀半空间电阻率,提出一种新的地形影响快速校正方法,即采用小极矩直流电阻率法获得无地形影响的表层电阻率值,作为地形校正的标准电阻率,以此构造一个新的校正公式.分别对CSAMT和TEM仿真和实际测量资料进行地形校正处理,效果较好.说明新的比值校正公式,是一种快速、有效和实用的校正算法.

A fast topographic correction method for electromagnetic data

Topography generally affects the electromagnetic data and will mislead the results of shallow layer's resistivity. In this paper, by analyzing the basic law of topography effect and classic ratio correction principle, it is feasible to replace the resistivity of uniform half space from numerical simulation by standard measured resistivity. We proposed a new fast method to correct the topographic effect in electromagnetic data. We obtain the surface resistivity without topography by using a small DC configuration, and then take it as standard resistivity to construct a new correction formula. Both synthetic and field data of CSAMT and TEM were processed using this method. Results show that the new method is a fast, effective and practical tool for topographic correction of electromagnetic data.