Based on the reported physical parameters for hexagonal system solids,we have calculated the effects of anisotropy on polarization of plane P-wave propagation.Herein we report the results of calculations and the newly observed physical phenomena.It is found that,for a given propagation,if the polarization is parallel to the wave vector,so also to the Poynting vector.In such a case,the phase velocity is identical to the energy velocity;the quasi P-wave degenerates to a pure P-wave along the propagation.It is also noted that if the polarization is parallel to the Poynting vector but not to the wave vector,the propagating wave cannot be a pure P-wave.Furthermore,the polarization in a quasi P-wave may deviate from the wave vector for more than 45°,but the deviation from the Poynting vector is always less than 45°.The energy velocity of a quasi SV-wave can be larger than that of the quasi P-wave in some propagation directions,even though the phase velocity of a quasi SV-wave may never be larger than either the phase velocity or energy velocity of the quasi P-wave.Finally,in case of parameters ε=0 and δ*≠0,the polarization of a quasi P-wave has an observed symmetry at a 45°phase angle.The anisotropy of a hexagonal system solid determines if a pure P-wave can be created and what the propagation direction is for a plane wave propagating inside such a hexagonal system solid.
FA LinZHAO MeiShanLIU YongChangWANG LeiWANG YanQiangSUN JiGang
Based on an acoustic logging transmission network and the engineering pattern of a sliding wave in acoustic logging, analysis and calculations have been performed in a study of the effects of the electric-acoustic and acoustic-electric conversions of the transducers on the acoustic logging signal. The results show that acoustic-electric conversion through the transducer can cause not only a serious disturbance in the signal amplitude, but also an apparent transmission delay. For engineering applications, the amplitude variation and transmission delay must be accounted for in a practical analysis of the acoustic logging signal in rocks. The results also show that with enhanced understanding and proper justification, the error caused by the acoustic-electric conversion can be significantly reduced in evaluation of the cement bond quality of a cased well, and the accuracy of rock porosity calculated using the measured acoustic velocity can be increased.
FA LinXIE WenYanTIAN YongZHAO MeiShanMA LiDONG DaQun
