弹性地层井眼中伪瑞利波的群速度

本文介绍了弹性地层中伪瑞利波的频散方程，对伪瑞利波的频散特性作了详细分析。文中 了给定条件下各支伪瑞利波的相速度起点，证明了在起点不存在伪瑞利波的群速度。并给出了从第三支群速度曲线开始出现的若干条鱼钩状曲线，推演说明在弹性地层的井眼中，伪瑞利波不可能以横波速度传播，但其群与横波速度可以非常接近。

Group velocity of pseudo Rayleigh wave in the borehole penetrating elastic formations

The frequency dispersion equation of pseudo Rayleigh wave in elastic formation is presented here, and its frequency dispersion characteristics are analysed in detail. Initial point of phase velocity of each pseudo Rayleigh wave in a given condition is determined theoretically, and it is proved that there is no group velocity of pseudo Rayleigh wave at initial point. Some "fishhook" curves are also given which appear from the third group velocity curve. Theoretical deduction says that in a borehole penetrating elastic formations,pseudo Rayleigh wave does not take shear-wave ve-locity, but its group velocity may be very close to shear-wave velocity.