横向各向同性介质中的地震波传播特性

在各向异性介质中 ,地震波的传播特性随传播方向而变化 ,常表现为地震波传播的相角和群角、相速度和群速度的不一致性。应用理论模型计算方法研究了具有垂直对称轴的横向各向同性介质中P波、SV波的传播规律和Thomsen参数对P波相速度的影响。计算表明 ,横向各向同性介质中的P波与SV波的相速度曲线不再是各向同性介质中的圆形。就相速度而言 ,在垂直方向附近 ,SV波的速度变化要比P波明显得多 ;Thomsen参数vS0 对P波相速度的影响非常小。研究结果对各向异性介质中的弹性参数反演、速度反演、NMO、DMO及时间域的偏移有着重要意义。

Propagation characteristics of seismic waves in transverse isotropic medium

The propagation characteristic of seismic wave In anisotropic media varies with the propagation direction. It usually shows that the phase angle (or phase velocity) of the seismic wave differs from that of the group angle (or group velocity). On the basis of Thomsen's parameters, the features of P wave and SV wave, and the effects of Thomsen's parameters on their features are studied using theoretical models and calculation method. The results show that the curves of the phase velocities of P wave and SV wave in vertical transvers isotropic media are not circular shaped. In the horizontal direction, the phase velocity of SV wave changes more obviously than that of P wave.The contribution of parameter v S 0 for the P wave phase velocity can be negligible, which is very important for the elastic parameter inversion, velocity inversion, normal moveout correction, dip moveout removal and migration in time domain.