多源全波形瞬变电磁虚拟波场三维Born近似反演与有限元逆时偏移成像

为了发挥多源地空瞬变电磁的工作优势，实现深部矿产资源的电阻率成像与构造反演，保障国家矿产资源供给。本项目首先利用多源等效导电平面法进行瞬变电磁数据近似解释，实现虚拟波场速度建模；采用全波形波场变换方法，将多源瞬变电磁数据转换成多源虚拟波场数据；在波动方程条件下利用Born近似实现波动方程参数反演构建虚拟波场三维速度模型与地下介质电阻率；在已知虚拟波场震源子波函数情况下，利用有限元波场延拓方法与多源偏移成像技术基于互相关成像原理, 实现多源虚拟波场有限元逆时偏移，完成地下矿产资源的构造反演，为深部找矿提供构造特征与电阻率信息。最后将本项目研发的多源瞬变电磁偏移成像解释方法应用与实际的矿产资源探测，通过与地质资料进行对比，验证方法的稳定性与有效性。

In order to play to the advantages of multi-source semi-airborne transient electromagnetics method, realizing the resistivity imaging and structural inversion of deep mineral resources. This project first uses the S-inversion method for the approximate interpretation of the transient electromagnetic data. Next, adopts the full waveform wave field transformation method to convert the multi-source transient electromagnetic data into multi-source virtual wave field data. Then, uses Born approximate inversion to realize wave equation parameter inversion to construct a virtual wavefield three-dimensional velocity model and underground medium resistivity. When the virtual wavefield source wavelet function is known, the finite element wavefield continuation method and multi-source migration imaging technology are used to realize the multi-source virtual wave field finite element reverse time migration, based on the mutual interaction relevant imaging principle, and provides structural characteristics and resistivity information for deep prospecting. Finally, the application of the multi-source transient electromagnetic migration imaging interpretation method developed by this project is applied to the actual mineral resource detection, and the stability and effectiveness of the method are verified by comparison with geological data.