DIPOLE LOGGING TOOL

摘要

A logging tool having a tool body, which can be positioned in a fluid-filled borehole, including a receiver section and a dipole transmitter; wherein the dipole transmitter includes a transducer with a shell having a reaction mass and a motor located therein, the motor operatively connecting the shell and the reaction mass such that only an outer surface of the shell is in contact with the fluid in the borehole. This new type of dipole source for well logging involves shaking all or part (axially) of a dipole tool body to produce a pure, broadband acoustic dipole signal while at the same time coupling as little energy as possible into the tool body. Important variations on this idea include a linear phased array of shaker sources, and active cancellation of tool borne noise.