分别采用传递矩阵法和有限差分法数值模拟了由多根钻杆和接箍组成的钻柱中的纵波的传输特性,得到了钻柱脉冲响应的频谱曲线。结果表明:可以根据钻柱具有的通带和阻带的传输特性来选择发射信号的频率,使声波信号通过钻柱传输或者被衰减掉;当钻柱较长时,传递矩阵法比有限差分法计算的结果更可靠。
Transfer matrix method and finite difference method were used to get frequency spectra of impulse response to simulate the transmission characteristics of longitudinal wave traveling through the drill string composed of multiple drill pipes and collars. The results show that the emission signal frequency can be selected according to the transmission characteristics of pass bands and stop bands, so as to make acoustic waves propagate or attenuate through the drill string. The transfer matrix method is more reliable than the finite difference method when the drill string is long.