弯曲模式声波在充液井孔中的传播
Propagation of flexural modal waves in a fluid-filled borehole
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摘要: 本文由波动方程讨论了充液井孔中,弯曲模式声波在弹性和非弹性、无限大井壁介质以及有限大井壁介质情况下沿井轴方向的传播。数值计算了它们的相速度频散曲线和井孔的频率响应特性,计算了衰减正弦信号在井孔中激励的波形。利用PZT压电晶片的弯曲振动模式,制作了偶极子测井换能器,在混凝土浇注的人工模拟井中进行了测试,试验结果与理论计算结果作了对比。Abstract: The propagation of multipole modal waves along the well-axis in a fluid-filled borehole surrounded respectively by elastic and nonelastic, infinite and finite formations is analyzed from the wave equations. The phase velocity dispersions and the exicitation curves are numerically calculated. The waveforms excited by attenuating bursts are also calculated. Measurements with long-spacing dipole transducers made of PZT thin diske vibrating in bending mode are carried out in a concrete model well and the experimental results are compared with the theoretical results.