材料期刊网

Acoustic telemetry along the drill string helps to know the physical and chemical characteristics of the formation and drilling fluid. A time-domain algorithm is developed for the propagation of one-dimensional axial stress waves with the inner and outer viscous fluid. The algorithm simulates the passbands, stopbands and spikes due to the presence of the discontinuous boundaries of drill string. Then the effects of transmitted pulses and transceivers on acoustic transmission are analysed. The simulated results show that the raised cosine pulses and optimal placements of transceivers improve system performance. Moreover, dual PZT receivers can exclude signals propagating in a direction opposite to the transmitted signals.It is obvious that the uses of the available modeling and signal processing techniques can make the drill string as a waveguide for transmitting information at high data rates.