MONOPOLE ACOUSTIC TRANSMITTER RING COMPRISING PIEZOELECTRIC MATERIAL

摘要

A monopole acoustic transmitter for logging-while-drilling comprising as a ring that comprises one or more piezoelectric arc segments. The ring is oriented in a plane whose normal is essentially coincident with the major axis of a logging tool in which it is disposed. The ring disposed within a recess on the outer surface of a short, cylindrical insert. The insert is inserted into a drill collar, rather than into the wall of the collar. The ring can comprise a continuous ring of piezoelectric material, or alternately arc segments or active ring segments of piezoelectric ceramic bonded to segments of other materials such as alumina to increase the frequency or heavy metals such as tungsten to reduce the frequency. The material and dimensions of the material used in-between the piezoelectric segments is chosen to alter the frequency of the ring.

主权项

1. A LWD logging tool acoustic transmitter comprising:
a transmitter ring comprising a single, continuous arc segment of piezoelectric material upon which bands of electrode material have been applied to a surface of the single arc segment of piezoelectric material; wherein
the ring is disposed within a transmitter ring assembly that is disposed within an insert comprising a flow conduit, is disposed within a drill collar rather than into a wall of the drill collar of the logging tool;the normal of said ring is essentially coincident with the major axis of the logging tool; andthe single, continuous arc segment of piezoelectric material is polarized and configured electrically to emit a pressure pulse perpendicular to the normal upon application of a voltage to at least one of the bands of electrode material.