Abstract: A transverse-wave logging tool consists of a plurality of sets of transducers mounted around a cylindrical mandrel. The transducer active faces are characterized by two orthogonal dimensions, one of which dimensions is a half-wavelength long relative to the acoustic excitation energy applied to a transmitter transducer and the transverse-wave formation velocity. Receiver transducers detect converted-compressional waves resulting from transverse waves that were generated by the acoustic excitation energy.

Abstract: A method for monitoring the relative goodness of a cement bond to a borehole casing by observing the relative change in amplitude of a converted-compressional wave as a function of depth in the borehole.

Abstract: An improved transducer for generating and receiving acoustic energy. A transducer core is constructed by bonding together a plurality of concentric cylinders to provide a ferromagnetic core. A magnetic vector is established circumferentially about the core by passing a current through an electrical winding, wound torridially about the core. A pulsed current source connected across the core provides a high-magnitude, short-duration pulse output establishing current flow from one end to the other end of all of the concentric cylinders. Current flow within the magnetic field causes a force vector and magnetic vector creating a pressure wave.

Abstract: Method and apparatus are provided for measuring acoustic signals having amplitudes of widely varying magnitude during one traversal of the borehole corresponding to indications of cement bonding along a casing as well as acoustic travel time through an increment of the formation. Variable attenuators are provided associated with acoustic receivers disposed within the logging sonde wherein attenuation may be automatically adjusted as a function of acoustic transmitter-receiver trigger pulses transmitted downhole, depending upon whether a cement bond or other log of acoustic signal information having a substantially different magnitude is desired.

Abstract: Apparatus for aiding a well logging instrument in traversing highly deviated boreholes including a plurality of extensible arms mounted in the elongated logging instrument, each arm terminating in a pad member which includes a toothed wheel or gear mounted therein but extending outside the pad. When the arms are extended, moving the pad members outward and away from the logging instrument toward the borehole wall, the toothed wheels engage the mud cake or the borehole wall. A motor is effectively connected to the toothed wheels through a plurality of shafts, universal joints and interconnecting gears for rotating the toothed wheels to move the logging instruments up or down the borehole length. By mounting the toothed wheels within the pad members at an angle other than parallel to the axis of the borehole such that an auger-like movement of the logging instrument is produced, the drive force exerted on the logging instrument is amplified.