有限差分法大地电磁多参数偏移成像

提出一种改进的有限差分法进行大地电磁场偏移成像,通过保留波数对水平方向的一阶导数项,使差分方程精度和成像分辨率得到了提高,并采用快速近似反演结果作为对背景电导率的客观估计,对两种极化模式联合成像以及多参数和再次成像进行了研究,通过模型试验和实例说明有限差分法大地电磁多参数成像技术解决复杂问题的能力,证明了该方法的有效性和实用性.

MULTI-PARAMETER MIGRATION IMAGING OF MAGNETOTELLURIC DATA USING FINITE DIFFERENCE METHOD

Based on systematic study of EM imaging techniques, this paper summarizes the achievements carried out by former researches and points out the limitations of simple model tests. The paper puts forward the migration imaging technique of magnetotelluric data by introducing an improved finite difference method and using the experience of Zhdanov for reference, which increases the accuracy of the difference equation and the imaging resolution by preserving the first order derivative of wave number in horizontal direction. Moreover, the paper also makes further researches on selecting of the suitable conductivity background by adopting the rapid approximate inversion result, joint imaging of two polarizaed modes, multi parameters and second process imaging. Based on the results of the synthetic and the real field observed MT data, the provided multi parameter migration imaging technique has been tested as a more accurate and effective measures for MT data imaging, especially for the study of complicated geological problems.