中文摘要：

采用有限差分方法研究钻井液黏滞阻尼、地层阻尼系数及弹性系数、钻杆数量及钻铤的存在对钻柱中通带声波传播特性的影响，分析声波时域及频域分布。结果表明：钻井液黏滞阻尼影响声波在钻柱中传输的时域分布，但对声信号幅值及频域分布影响较小；地层阻尼系数影响大振幅声信号幅值及小振幅声信号分布，地层阻尼系数越大．大振幅声信号振幅略有减小，地层阻尼系数越小，小振幅声信号振动增多，振动杂乱；地层弹性系数影响声信号振动幅值，地层弹性系数越大，声信号幅值越大；钻杆数量影响声波的时域分布，钻杆数量越多，接收到的声信号幅值越小：在不考虑衰减的情况下，钻铤不影响声波的传播特性；钻柱结构对载波频率的选择起主要作用，其他因素及钻柱结构对中继装置的分布有影响。

英文摘要：

Using the finite difference method, the transmission characteristics of the acoustic wave in the passband transmitting through the drill string were researched, and the influences of the viscous damping of the drill fluid, the formation damping co- effieient and elastic coefficient, the number of drill pipes and the existence of the drill collar were analyzed. The wave time do- main and frequency domain distributions were analyzed. The results show that the drilling fluid viscous damping has effect on a- eoustie wave time domain distribution, and has little effect on the acoustic wave signal amplitude and frequency domain distri- bution. Formation damping coefficient has effect on amplitude of the large amplitude acoustic wave and time domain of small amplitude acoustic wave. The amplitude of large amplitude acoustic wave is slightly smaller when the formation damping coeffi- cient is big, and vibration of small amplitude acoustic signal becomes messy when the formation damping coefficient is small. Formation elastic coeffieient has effect on vibration amplitude of acoustic wave, and the vibration amplitude of acoustic wave in- creases with the formation elastic coefficient increasing. Drill pipe quantity has effect on acoustic wave time domain distribu- tion, but has no effect on the frequency domain distribution. With the drill pipe quantity increasing, the received acoustic wave amplitude reduces. The drill eollar has no effect on acoustic transmission properties in drill string without eonsidering the atten- uation. The drill string structure plays a major role for the seleeted carrier frequency, and the other faetors and drill string structure have effect on the distribution of relay device.