阵列声波测井传输网络指向性及互易性分析

在声波测井中声束导向的效率除受换能器的几何参数及阵列声波发射单元的激励延迟时间或阵列接收器接收的各道声波信号偏移时间的影响外 ,还受换能器的形状和尺寸的影响。一般声波测井仪是由一维阵列声源和单接收器或由单声源和一维阵列接收器组成。换能器为薄圆管形压电换能器。采用相应的声波测井传输网络理论和指向性权系数的概念 ,计算了换能器的形状及大小对声束导向信号所造成的影响 ,并论证了声波测井仪中阵列声源和阵列接收器的互易性。通过调整声束导向参数和阵列接收器接收到的声波信号的时间偏移量 ,可使得接收首波幅度 (阵列声源 )和叠加波首波幅度 (阵列接收器 )最大。此外 ,运用数值模拟和实验对文中提出的最佳设计方案进行了验证

On Directivity and Reciprocity of Array Sonic Logging Transmission Network.

The shape and size of transducers, array geometry and excitation delay of source array and the shifting time of acoustic signals received by receiver array affect the efficiency of acoustic beam steering in acoustic logging. The transducers in acoustic logging tool are usually cylindrical piezoelectrical transducers and their acoustic radiation and acceptance have preferred directivity. Utilizing a corresponding acoustic logging transmission network and the concept of directivity weight coefficient, we have calculated the effect of both the shape and size of transducer and the array geometry on the acoustic beam steered logging signal and verified the reciprocity between a source array logging tool (which consists of a source array and a single receiver) and a receiver array logging tool (which consists of a single source and a receiver array). By adjusting the excitation delay and the shifting time, the source array logging tool and the receiver array logging tool can increase the received and stacked acoustic logging signal amplitudes respectively. The double array logging tool (which consists of a source array and a receiver array) can improve the processing preciseness of acoustic logging signal parameter for the same processing algorithm and increase the amplitude of the logging signal greatly compared with above two kinds of single array acoustic logging tool. Experimental data qualitatively validate the optimal design method for the logging tool presented in this paper.