纵横波分离的多震源弹性波全波形反演

Multi-source elastic full waveform inversion based on P-wave and S-wave separation

弹性波全波形反演(EFWI)具有获取高精度纵、横波速度和地层密度的潜力,但计算成本高。纵、横波耦合会引起串扰噪声,降低反演精度。多震源编码技术能大大提高EFWI的计算效率,但会增加波场的复杂度,致使非线性问题更严重。为此,提出一种基于纵、横波分离的多震源弹性波全波形反演(ES_SEFWI)方法,通过动态震源随机编码技术压制多震源串扰噪声,同时采用波场分离技术缓解纵、横波耦合引起的串扰效应。纵、横波速度结构相关的Marmousi模型和纵横波速度结构不相关的Marmousi-Ⅱ模型测试结果表明,所提反演方法能有效压制串扰噪声并提高计算效率。

The elastic wave full waveform inversion(EFWI)can obtain high-accuracy P-wave and Swave velocity,and density,but the computational cost is rather high.The P-wave and S-wave coupling causes crosstalk noise and decrease inversion accuracy.Multi-source coding can greatly improve EFWI calculation efficiency,but increasing the wavefield complexity,leading to more serious nonlinear problems.In this paper,a multi-source elastic wave full waveform inversion method based on P-wave and S-wave separation is proposed.The method uses dynamic random coding to suppress multi-source crosstalk noise,and uses wavefield separation to mitigate crosstalk effects caused by the P-wave and S-wave coupling.The proposed method is tested on the Marmousi model with consistent P-wave and S-wave velocity structures and on the Marmousi-II model with uncorrelated P-wave and S-wave velocity structures.The results show that the inversion method can effectively suppress crosstalk noise and improve computational efficiency.