Abstract: In preferred embodiments described herein, a transducer head is affixed to the lower end of a wireline borne scanner sub for rotation thereby. The transducer head includes a pair of transducers which may be adjusted radially inward or outward with respect to the head so that optimum standoff may be achieved without the need for numerous transducer heads of various sizes. In a described exemplary embodiment, the transducers are adjusted by means of an indexing system which permits fine control over the amount of adjustment for the transducers.

Abstract: An apparatus for logging a borehole comprises a non-rotating component and a rotating component that is flexibly attached to the non-rotating component and includes a logging head. The rotating component is centralized independently from the non-rotating component such that the rotating component remains centralized as it rotates, regardless of whether the non-rotating component is centralized. The logging head includes at least one signaling device, a hydrostatic pressure balancing system, a sealed, variable-volume fluid reservoir in fluid communication with said transducer, and a motor housed in said logging head for rotating the rotating component. The apparatus can further include a second non-rotating component suspended below the rotating component.