“…This work aims to explore an ultrasound Doppler method which can be directly applied to existing LWD tools used for imaging the borehole wall. Publications on LWD field measurements from leading drilling companies indicate the use of ultrasonic transducers in a frequency range of 100 kHz-1 MHz (Shrivastava et al, 2019;Blyth et al, 2021;Maeso et al, 2018;Longo et al, 2012;Leonard, 2016). These publications also suggest the use of unfocused transducers, although focused transducers have also been reported in some papers.…”