三分量定源瞬变电磁解释技术及其在金属矿区的实验

Three-component interpretation technique of fixed source TEM and its experimental application in metallic ore district

目前的瞬变电磁仪器已经为三分量瞬变电磁解释提供了硬件基础,但瞬变电磁的实用解释技术仍局限于对垂直分量的解释或一些简单近似技术。为充分利用三分量数据,进一步提高定源瞬变电磁方法的分辨率,针对定源瞬变电磁装置给出三分量全域视电阻率定义和三分量联合一维反演的方法。在进行全域视电阻率定义时,利用迭代求取反函数值的方法替代直接求取反函数的过程;引入三分量瞬变电磁数据的权重以构建联合三分量数据的目标函数,利用可行域法实现三分量联合一维瞬变电磁反演;最后将三分量解释算法分别应用在模型计算和金属矿的实际勘查资料上,以检验其有效性。模型试验和实际资料处理结果表明,三分量解释方法能够利用更多的瞬变电磁数据,获得更高分辨率的处理结果,且具有较快的计算速度。

The TEM instruments have provided a hardware foundation for three-component TEM interpretation; nevertheless,the practical interpretation technology is still confined to the vertical component or simple approximation techniques. To make full use of the three-component data and improve the resolution of the fixed source TEM,this paper put forwards the three component full domain apparent resistivity definition and one-dimensional three-component joint inversion method. For the full domain apparent resistivity definition,the authors use the iterative method to calculate the inverse function value instead of directly calculating the inverse function. The authors introduce the three-component weights of TEM data to build the joint objective function,and use the feasible region method to implement three-component joint inversion. Finally,the three-component interpretation algorithm is applied to the model calculation and the actual exploration data of the metallic mine to verify its effectiveness. Model test and actual data processing results show that the three-component interpretation method can use more TEM data and obtain processing results with higher resolution,thus achieving a fast calculation speed.