基于快速拟线性积分方程法的大地电磁三维正演研究

Three dimensional magnetotelluric forward study based on fast quasi-linear integral equation method

三维大地电磁测深正演所用的时间长与占用的内存大的缺陷是如今国内外学者一直致力研究的问题.本文首先开展基于拟线性积分方程的大地电磁三维正演研究,通过压缩格林系数矩阵减少了庞大的计算量,达到了快速生成系数矩阵的目的,实现了快速拟线性近似的方法.然后,本文设计了不同背景的理论模型,对理论模型进行了快速拟线性积分方程法和积分方程法的正演模拟试算.正演模拟结果表明:采用快速拟线性积分方程法的正演视电阻率曲线与积分方程法求得的视电阻率曲线结果基本相同,表现出较高的准确性,并且快速拟线性积分方程法具有更快的计算速度,特别当地下剖分块数增大时,正演计算效率更为明显.

It is a problem that domestic and foreign scholars have been devoting to studying now that the defects of long time and occupied memory of three dimensional magnetotelluric forward are.In this paper,firstly,the study of three dimensional magnetotelluric forward modeling based on quasi-linear integral equation is carried out. By compressing Green ＇s coefficient matrix,a huge amount of calculation is reduced,and a fast coefficient matrix generation is achieved. A fast quasi-linear approximation method is achieved.Then, this paper designs a theoretical model with different backgrounds and conducts a forward modeling test of the fast quasilinear integral equation method and the integral equation method for the theoretical model. The forward simulation results show that the apparent resistivity curve obtained by forward quasi-linear resistivity curve and integral equation method using fast quasi-linear integral equation results are basically the same,showing higher accuracy,and the quasi-linear integral equation method With faster calculation speed,especially when the number of local subdivisions increases,forward calculation efficiency is more obvious.