论文部分内容阅读
本文利用偶极子合成回线方式计算了回线源一维瞬变电磁场.首先推导了水平电偶极子和垂直磁偶极子合成方回线源瞬变电磁场的计算公式,并对部分计算过程做了改进.然后将这两种算法在方回线中心点计算结果分别与面积相同的圆回线中心点解作对比,并分析了积分方式和回线框大小对计算精度的影响,得到下述三点认识:(1)在早期道,偶极子合成回线正演相对误差较大,但随着测量时间道的增加,相对误差减小;(2)对于电偶极子合成方回线的正演,一般采用高斯-勒让德5点求积便可达到最高精度,对于磁偶极子合成方回线正演,一般回线框越大,便需要更精细的积分才能达到最高精度;(3)偶极子合成方回线中心点正演在早期存在较大的误差并非由计算方法导致,而是等效面积相等的方回线和圆回线激发的二次磁场本身存在差异所致.最后利用偶极子合成回线正演方式可以较准确的计算回线框内外任意一点的瞬变电磁场,将为回线源瞬变电磁全区勘探和一维反演提供理论指导.
In this paper, the dipole synthesis loop was used to calculate the one-dimensional transient electromagnetic field.Firstly, the formula for calculating the transient electromagnetic fields of the horizontal line dipole and the vertical magnetic dipole was deduced, Then the two algorithms are respectively compared with the center point of the circular loop with the same area in the center line and the influence of the integral method and the size of the loopback box on the calculation accuracy is obtained, The following three points are recognized: (1) In the early stage, the relative error of the dipole synthesis return forward is larger, but the relative error decreases as the measurement time increases; (2) For the dipole synthesis side Loop forward, the general Gaussian - Legendre 5 points product will be able to achieve the highest accuracy, for the magnetic dipole synthesis side line forward, the general return line frame, you need more elaborate points to achieve The highest accuracy; (3) dipole synthesis square loop center point forward in the early existence of a larger error is not caused by the calculation method, but the equivalent area is equal to the square loop and circular excitation of the secondary magnetic field itself There is a difference caused by the last dipole synthesis loop back forward mode Which can accurately calculate the transient electromagnetic field at any point inside and outside the wireframe and provide theoretical guidance for the whole area transient electromagnetic exploration and one-dimensional inversion of the loop source.