ABSTRACT
Acoustic energy is mechanical energy in wave (or pulse) form in the "acoustic" frequency range (usually presumed to be about 10 to 105 Hertz). It is transmitted through a material by mechanical oscillatory movement of the molecules of the material. The velocity of a wave type through a single material is characteristic of that material and its physical environment. The velocity of a particular wave type in a multi-mode material is a function of the sum of the partial velocities of the material. In usual borehole geophysical logging practice, a mechanical pulse is put into the borehole fluid from a transducer. When the pulse contacts the wall of the hole, its velocity changes and the pulse continues in the solid formation material as several different types of waves, each at a different velocity. The velocity will depend upon the average physical parameters of the formation material and upon the type of wave being considered.
