二维频率测深边界单元法正演计算

BOUNDARY ELEMENT METHOD FOR FORWARD SOLUTION OF TWO DIMENSIONAL FREQUENCY ELECTROMAGNETIC SOUNDING

在二维层状介质中含有横向非均匀体的地电断面情况下，对电偶源的偶极长度作了延长，并选取了适当的基本解及无穷远边界条件，因而将相应的含源谐变电磁场的边值问题转化为较简单的边界积分方程．用边界单元法求出了相应的电磁场分量，进而计算阻抗视电阻率，并对这一算法作了相应的检验．

The boundary element method is used to calculate the impedance apparent resistivity in frequency electromagnetic sounding for the model of layered medium which contains a two-dimensional inhomogeneous body.In the modelling,the line source of harmonic-varying current is taken,and proper fundamental solution and infinite boundary condition are selected,so that the boundary value problem of the electric field of line source could be converted into a set of boundary integral equations that could be easily solved By the Boundary Element Method.Then the corresponding electromagnetic field and the impedance apparent resistivity could be calculated.Finally,some tests and comparisons of the results by Finite Element Method and Boundary Element Method are made.