钻井-地表电极联合电阻率观测装置的异常特征研究

本文利用有限单元法对多种钻井-地表电极联合电阻率观测装置在球体、直立板和水平板体等典型地质体模型上的异常响应进行正演计算，并分析其异常特征和分布规律.计算结果表明利用井中和地表电极的联合观测方式进行地下介质探测，可在兼顾地质体的水平分辨能力的同时，提高电阻率测深在垂向上分辨率.就水平分辨率而言，四极（偶极）装置对地质体的水平定位能力最强，井-地三极装置次之，地-井三极的分辨能力最差.就垂向分辨能力来说，各种观测装置的分辨率相差不大.

A study on anomaly of borehole-to-ground joint resistivity surveying system

Borehole-ground joint pole resistivity surveying system, which is one of the normal method in engineering prospecting, can detect the bodies in many bearings and close range. In order to study the anomalous feature of several hole-ground joint pole resistivity surveying array, the numerical modeling using FEM on some typical geologic bodies, such as sphere, vertical plate, horizontal plate, was done in this paper. The results show that hole-ground joint pole resistivity surveying system can improve vertical and horizontal resolution. As far as horizontal resolution is concerned, dipole-dipole array is the best one, hole-to-ground pole-dipole is better than ground-to-hole pole-dipole. There is little different to every hole-ground array in terms of vertical resolution. It is essential to distinguish the distinct configuration of apparent resistivity anomaly of every array in practice.