瞬变电磁多分辨全域波场变换算法研究

项目名称： 瞬变电磁多分辨全域波场变换算法研究

项目编号： No.41304114

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 戚志鹏

作者单位： 长安大学

项目金额： 25万元

中文摘要： 将瞬变电磁满足的扩散方程转变为波动方程，然后利用地震类成像方法实现瞬变电磁虚拟波场成像，是实现瞬变电磁三维反演的有效手段之一。波场变换是典型的不适定问题，如何根据瞬变电磁数据求取稳定高分辨的虚拟波场成为电磁成像领域的研究难点与瓶颈。本课题针对波场变换的不适定性，以及经典正则化反变换中存在的问题，提出了预条件多参数正则化迭代方法实现多分辨的波场变换。首先，根据核函数性质进行数值离散，依据系数矩阵数学性质构造合理的预条件矩阵，选择合适的迭代算法。然后，利用多维L曲线方法实现多正则化参数的求取。预条件处理可以有效降低方程的病态性，多正则参数迭代能够保证获得稳定多分辨的全域波场。最后，通过模型对算法进行验证，并给出波场分辨特性分析，利用实测数据对算法实用性进行检验。总之，项目研发的波场反变换算法将促进瞬变电磁拟地震的发展，为获得准确的地质解释提供基本保障。

中文关键词： 瞬变电磁；波场变换；正则化；扫时；延拓成像

英文摘要： The wavefield conversion is a useful way to achieve pseudo-seismic interpretation for Transient Electromagnetic Method (TEM). Wavefield transformation is typecally ill-posed problem. To deal with the problem, realized the Full-domain wavefield transformation from diffusion equation to wave equation, and acquired the stable fictitious wave are the hot issue and bottleneck of TEM 3D imaging. This project is aimed at realizing full-domain multi-resolution wavefield transformation by combining Pre-conditioned and adopting multi-parameter regulerization. Pre-conditioned Multi-parameter Regularized iterative algorithm has been proposed in this items, so that the TEM full-domain multi-resolution wavefield transformation could be executed.After the numerical discretization,we can construct the preconditioned matrix, choose the suitable iterative algorithm based on the mathematical properties of coefficient matrix, and acquire the multi regularization parameter with multidimensional L curve method. The pre-conditioned process effectively reduces the condition number of the coefficient matrix, while multi-parameter Regularization iterative Method helps run the inverse transformation of wavefield in full-domain.Through the sythtical data to validate the algorithm and analyse the wavefield distinguish characteristics. With

英文关键词： transient electromagnetic method；wavefield transform；regularization；time sweep；migration imaging