Experimental research on acoustic array sonde in borehole azimuthal reflection logging tool

Abstract

Phased combined arc array technology was adopted when designing acoustic sonde to enhance 3D detection capability and resolution in borehole azimuthal reflection logging tool. After constructing experimental measurement system, horizontal and vertical radiation characteristics of the transmitter with different phased excitation delays were tested in a 5 m*5 m*4 m water tank as well as consistency and phased combined effects for 80 array elements in 10 stations of the receiver. Also, this tool was placed in an open waters to explore the response of reflector including size, placed radial distance, and azimuth with optional phased excitation delay. Experimental results show that when the phased excitation delay is 30 us, the main lobe direction of vertical radiation energy of the transmitter could be up-deflected by 150 and less side lobe energy. The −3 dB width of main lobe is obviously narrowed using 3 array elements combination in receiver. This tool possesses the ability of recognizing a 2 m*1 m*0.05 m aluminum plate at 10 m radial distance which means about 40 m in real formation, the reflected wave energy intensity distributes symmetrically in eight directions. This work is helpful for acquiring performance of the tool and data processing.