Sensor design and characterization method for new multimode downhole sonic measurements

Downhole sonic measurements provide compressional and shear wave propagation speeds of formations for hydrocarbon exploration purposes. We developed a new logging-while-drilling (LWD) tool that provides shear speed measurements in oil wells that are drilled in slow formations, where shear head waves are not excited using the conventional monopole source. To provide quality multimode measurements, azimuthally distributed transmitter and receiver elements of good output or sensitivity matching are required. We designed such devices, characterized them in-house, and tested them in the oil wells. This paper introduces our downhole sonic tool development method, focusing on receiver characterization and results.