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作为声波阻抗的广义形式,当前地震勘探领域所应用的弹性阻抗描述了在地震纵波非垂直入射的情况下地层对反射纵波的阻抗特征,因此能够反映地层的横波速度信息.但是,根据其理论公式的推导,传统的弹性阻抗实质是反射波的一个衍生标量属性,且存在诸如弱阻抗差、小入射角和相邻地层纵/横波速度比恒定等假设条件.因此在相应的反射系数重构、地震反演与解释过程中不可避免地存在误差.通过分析各向同性弹性介质中速度场与应力场之间的关系,给出了弹性阻抗张量的精确公式表征.弹性阻抗张量能够表示每个应力分量与速度分量间的关系,因此完备地描述了介质的弹性力学特性.文章通过理论模型和实际数据应用证明了导出的弹性阻抗张量表达式较经典的弹性阻抗公式有更高的精度和适用范围.
As a generalized form of acoustic impedance, the elastic impedance applied in the current seismic exploration field describes the impedance characteristics of the formation to the reflected P-wave when the seismic longitudinal wave is not perpendicularly incident and thus can reflect the information of the S-wave velocity in the formation. However, according to its theoretical formula , The traditional elastic impedance is essentially a derivative scalar property of the reflected wave, and there are some assumptions such as weak impedance difference, small incident angle and constant ratio of adjacent longitudinal / transverse wave velocity. Therefore, after the corresponding reflection coefficient reconstruction, There is an inevitable error in seismic inversion and interpretation process.Through the analysis of the relationship between velocity field and stress field in isotropic elastic medium, the exact formula of elastic impedance tensor is given.The elastic impedance tensor can be expressed as The relationship between the stress component and the velocity component, so a complete description of the elastic properties of the medium.Through the theoretical model and the actual data application shows that the derived elastic impedance tensor expression than the classical elastic impedance formula has a higher accuracy And the scope of application.