中文摘要：

采用有限元法数值仿真了处于充液井孔中多根钻杆和接箍组成的钻柱系统中纵波的传播特性，并给出了纵波的声衰减曲线。研究结果表明：处于充液井孔中周期性钻柱系统具有的通带和阻带特性与理想钻柱系统相似，因钻柱周围流体介质的阻尼作用，会使钻柱中传播纵波的幅度减小，衰减增大。当沿钻柱传播的声载波频率位于通带内时，可降低声衰减量，提高信噪比，有利于提高随钻数据的传输速率。

英文摘要：

The finite element method is simulated the compressional wave propagation in the drill string system, assembled from drill pipes and threaded tools , in the fluid-filled borehole. And the decrement curve of the compressional wave is presented. The result shows that periodic drill string in the fluid-filled borehole has stop band and pass band , the same character as the perfect drill string system. Because of the damping effect of the fluid medium around the drill string, the acoustic wave propagation through the drill string has a amplitude decrease and a attenuation increase. When the sound carrier frequency is located within the passband, the attenuation can be reduced and the signal to noise ratio can be improved. This will help improve data transfer rate of logging while