Abstract:

According to the current situation in borehole imaging, the parameter of the cylindrical linear phased array (CLPA) transducer is selected and optimized on the basis of simulation of acoustics radiation field of CLPA transducer. A down-hole system for borehole imaging based on CLPA transducer is designed and manufactured. The system includes an acoustics cartridge, a circuit cartridge and ground control system. The acoustics cartridge is composed by the CLPA transducer to avoid mechanical rotation of the probe as the traditional ultrasonic borehole imaging device. The circuit cartridge is composed by a transmitter receiver module in high level of integration and a digital signal processing module based on FPGA and DSP architecture, completing the magnitude and the time information extraction of echo signal of borehole wall, and ultimately displaying real-time borehole imaging. Scanning and imaging experiments are carried out in test wells for different size of defects using this system. It is shows that the basic location and size information of the defects can be reflected in the borehole imaging by the ultrasonic phased array system designed and the CLPA has a good imaging ability.

Key words: borehole imaging, electronic scanning, ultrasonic phased array