Abstract: A method for measuring the thickness of casing in a wellbore and/or analyzing the inner surface of the cased or non-cased wellbore. The method includes an positioning an untethered logging tool in a drill string, receiving the logging tool in a catcher positioned within the drill string, positioning a plurality ultrasonic transducers with the average distance between the outer surface of the plurality of transducers and an interior surface of the catcher sub being less than 0.8 mm, and moving the drill string and the logging tool toward a mouth of the borehole while transmitting acoustic waves through the catcher sub toward the wellbore casing and receiving acoustic waves back to the logging tool after the acoustic waves interact with the wellbore casing and reflect through the catcher.