相控线阵声波辐射技术在反射声波测井中的应用探讨

The Effectivity of Applying Linear Phased Array Transmitter in Borehole Acoustic Reflection Logging

采用有限元方法对相控线阵声波辐射技术在反射声波测井中的应用进行探讨 ,从信号的幅度、能量和损耗等角度考察了相控线阵声波辐射器的相位加权和幅度加权对在井孔中接收到的反射纵波的影响。结果表明使用相控线阵声波辐射器可以明显提高在井孔中接收到的有用信号的信噪比 ;应用相控辐射器的相位加权和幅度加权技术 ,即调节相控线阵声波辐射器的相邻阵元间激励信号的延迟时间和信号幅度 ,可使各个阵元辐射的声波信号在介质的传播过程中某个给定方向上的能量最大 ,从而使反射纵波信号得到明显增强。

The effectivity of applying linear phased array transmitter in borehole acoustic reflection logging is investigated using the finite element method(FEM). The influence of phase weighing and amplitude weighing technique on the reflected waves from the borehole is discussed from the aspects of amplitude, energy and attenuation. Numerical results show that the ratio of signal to noise can be obviously improved when applying linear phased array transmitter. While adopting the technique of phase weighing and amplitude weighing, that is, regulating the fire delay time and signal amplitude between the neighbouring elements, the energy of the received waveforms in the borehole can be maximal in certain direction. As a result, the energy of the received reflected wave will increase. The technique presented provides a better theoretic base for the applications of linear phased array transmitter in borehole acoustic reflection logging.