高密度电阻率法比值参数基于阻尼最小二乘反演

三电位电极系中装置的探测精度和数据处理方法的研究一直是地球物理工作者研究的一个热点,同时也存在很大的争议。利用正演模拟结果讨论了岩溶地区几种可能存在的地质条件下三种装置的探测精度,发现β装置和γ装置的探测效果明显优于α装置;然后利用正演计算得到的数据合成比值参数(T),对合成数据T进行最小二乘反演,发现T值反演结果和视电阻率反演结果一致,并在噪声影响较大的区域,T值反演结果优于T值等值线图,可作为判断异常体特征的一个依据,也可验证视电阻率的反演结果,弥补由于噪声对某种单一装置探测效果的影响。以义马某地的水文地质勘察为例,T值最小二乘反演结果表明,在含水低阻区域T值也呈现小值异常,且显示的异常体边界准确,结构特征明显。利用T值反演对数据处理具有重要的意义,应予以重视。

The least squares inversion of high-density resistivity method ratio parameter based on smooth constraint

The detection accuracy of the array and the study of data processing methods about the three-potential observation system always constitute a hot spot for geophysicists,and there are also many controversies. In this paper,forward modeling results are used to discuss the detecting accuracy of three devices under several possible geological conditions in karst area. It is found that β array and γarray are significantly more precise than wenner α array;then,the ratio parameter( T) is composed of forward’s result. With leastsquares inversion on the data of T,the authors found that the result of T’s least-squares inversion is consistent with the inverse result of apparent resistivity,and the result of inversion result is better than the T contour map in an area where the noise is large. For the result of the T’s least-squares inversion,it can be used as a basis for judging the anomalous body characteristics and the inverse result of apparent resistivity,and it can also be used to make up the effect of noise on a single device. Taking the hydrogeological survey of a certain place in Yima as an example,the authors found that the result of the T’ least-squares inversion in the low-water-resistance region is small,the abnormal bodies’ boundaries are accurate,and the structural features are obvious. It is shown that the result of the T leastsquares inversion is very useful for data processing and interpretation,and therefore researchers should pay attention to it in future.