Experimental simulation of obtaining the reflector azimuth using azimuthal acoustic reflection tool in the underwater environment

Abstract

The azimuth and distance of reflector from the logging tool can be obtained by downhole azimuthal acoustic reflection measurements and the supporting reflection logging tool was developed. The special azimuthal acoustic receiver sonde of the tool results in azimuthal acoustic data, permitting the evaluation of the reflector location by reflected P-waves. Eight transducers distributed evenly across the receiver can record acoustic waves independently. Each receiver can be considered as belonging to an eight-element arcuate phased array, which allows us to adopt the beamforming method. To evaluate the feasibility of reflector azimuth measurements and the effectiveness of beamforming in azimuth acoustic data, an experimental simulation was conducted in a deep lake. Experimental results reveal that the reflector azimuth can be easily determined with the maximum amplitude value of reflected P-waves. Furthermore, the relationship between the amplitude value of beamformed reflection and azimuth suggests a higher measuring accuracy of azimuth. The results also show that the azimuths of double reflectors arranged opposite to each other can be obtained. The consistency between measured and actual values reveals the reliability of data processing. This work shows a promising prospect in the downhole application of determining the reflector azimuth using this tool in the future.