CHARACTERIZATION OF CAPACITIVE MICROMACHINED ULTRASOUND TRANSDUCER (CMUT) FOR TARGETED APPLICATIONS IN HARSH ENVIRONMENTS

Acoustic borehole televiewers commonly employ piezoelectric transducers for borehole imaging in exploration projects. However, conventional transducers are large and under harsh environmental conditions, such as high temperature geothermal explorations, have thermal limitations. This work investigates the feasibility of using CMUT, which can operate at high temperatures (intrinsically due to its non-piezo based structure) for borehole applications. We designed a transducer housing that would comply with the conditions of borehole probes and characterized the transducer individually for transmit and receive performances. The results indicate that a CMUT can deliver measurable signals through drilling mud and can be adapted for use in borehole imaging.