频率域全波形反演中关于复频率的研究

Studies on complex frequencies in frequency domain full waveform inversion

Laplace-Fourier域全波形反演可以利用简单的初始模型,从缺失低频信息的地震数据中得到长波长速度模型.Laplace-Fourier域全波形反演等价于本文的复频率全波形反演,但二者的实现方式不同,因此研究复频率全波形反演,可以为二者的对比研究并发展更有效的方法奠定重要基础.本文首先比较用线性增加模型作为初始模型时几个包含不同高低频成分的频率组的反演效果,再比较结合复频率之后各个频率组的反演效果,从简单模型和复杂模型的测试中都可以看出这种复频率+频率反演的方式对反演效果有明显改善.

Based on a simple starting model, Laplace-Fourier domain full waveform inversion （FWI） can recover a long wavelength velocity model from seismic data lacking low-frequency information. Although Laplace-Fourier domain FWI is equivalent to complex-frequency FWI, their implementation details are different from each other. Therefore, studies on complexfrequency FWI can lay a good foundation for comparison between the two and for developing a more efficient approach. In this paper, we first compare frequency domain inversion results of different frequency groups from an initial velocity model that increases linearly with depth （let＇s call it linear complex freq lncrea ueneles sing velocity model later）. Then we combine these frequency groups with to do FWI and also compare the inversion results, tests on simple and complex velocity model both show that this complex-frequency-plus-frequency inversion style helps improve the inversion results.