层状介质井中电测数值计算及其应用研究

采用Gauss Laguerre求积公式对层状介质井中电测地-井方式的ΔV1（电位梯度）、ρa参数进行了理论计算.大量的正演数据揭示在层状介质情况下，井中电测地-井方式观测可以获得台阶异常，与相应的地电层相对应；低阻覆盖层和中间低阻层对井中电测影响很大，厚层覆盖区对地-井方式观测不利；水槽模拟和应用实例表明，分析实测资料时，要考虑层状介质ΔV1、ρa的正常场特征，对实测数据进行正常场改正，分析正常场改正后的ΔV″1异常效果较好.

Numerical calculation of borehole electrical survey in layered media and its applications

The integral formula of Gauss Laguerre has been imployed to theoretically calculate ΔV1 (potential gradient) and ρa of the surface borehole method of borehole electric exploration. Lots of forward calculation data show that the survey of surface borehole method can obtain step anomalies under the layered media condition，which correspond to geo electric layers. Over burden low resistivity layers and sandwich low resistivity layers have large influence on borehole electric survey results. Heavy overburden is harmful to this kind of the working method. When interpreting field dada, the normal field feature of ΔV1 and ρa must be considered. Analysis of the abnormal field ΔV″1 from the corrected normal field can achieve good effects.