CSAMT电场单分量视电阻率定义在地热资源勘探中的应用

Single Component Apparent Resistivity of CSAMT Defined by Electric Field in the Application of the Geothermal Resource Exploration

可控源音频大地电磁法(CSAMT)是目前地热资源勘探中主要的地球物理方法之一,通过计算相互垂直的电磁场分量的比值来定义卡尼亚视电阻率,进而实现远场情况下的中、深部目标体的探测。但是,对于强干扰地区,当电场分量和磁场分量受到的干扰差别较大时,卡尼亚视电阻率会引起较大的计算误差。利用电场或磁场单分量定义视电阻率能更准确地解释地下的电性结构。从理论模型和野外实践两方面证明单分量视电阻率定义的可行性,取得了理想的效果。

CSAMT is one of the major geophysical methods in the geothermal resource explol：ation. The far-field large-depth exploration is realized using the Cagniard resistivity, which is defined through calculating the ratio of the orthogonal horizontal components. However, large error will be caused for the different sensitivities of electric or magnetic field to the noise. Single-component apparent resistivity based on the formulas of electric field or mag- netic field will reduce the error greatly. In this paper, single-component resistivity is proven feasible by theoretical models and field example, which achieves the desired results.