电导率分块线性变化的二维高频大地电磁法有限元正演模拟

THE FINITE ELEMENT METHOD FOR MODELING 2-D HIGH-FREQUENCY ELECTRO MAGNETIC WITH CONTINUOUS VARIATION OF CONDUCTIVITY WITHIN EACH BLOCK

为了适应电性参数在水平方向和垂直方向是连续变化的实际需要,这里采用矩形剖分,线性插值的有限元法研究了电导率分块线性变化的高频大地电磁高精度,快速正演模拟。首先给出了二维高频大地电磁测深的变分问题以及电导率分块线性变化时的有限元数值解法,编制了相应的有限元程序。利用该程序对层状模型进行了计算,并与解析解的结果做了对比分析,证明了程序的正确性和有效性,然后对典型电导率随深度线性变化的模型和典型地堑模型进行了正演模拟,结果表明能够有效地解决电导率在水平和垂直方向分块线性变化的高频大地电磁正演问题。

In order to meet the actual needs of the electrical parameters' continuously changes in the horizontal direction and vertical direction,this paper studies high-frequency electromagnetism's high precision of piecewise linear variable conductivity and its fast forward modeling.First,given the two-dimensional high-frequency electromagnetic variation problems,the finite element method to simulate logging when conductivity is piecewise linear variable,and developed a corresponding finite element program.Calculating a layered model with this procedure,and comparing it with the analytical results,it proves the correctness and effectiveness of the program.Then the conductivity with depth for a typical linear model and a typical rift valley model are forward modeling,the results show that the conductivity in the horizontal and vertical direction can be effectively solved in piecewise linear variable electromagnetic forward modeling problem.