© 2003 - 2007 WELLOG All Rights Reserved PART II, PAGE 2 The
interaction of acoustic waves in a rock matrix affect velocity
and attenuation of the acoustic signal. Rock density, porosity,
saturation and fracturing have different affects that contribute
to a very complex acoustic signal which contains an abundance of
information. Acoustic tools are designed to generate an acoustic
signal (sound wave) having significant energy that will travel
through the borehole fluid, rock formation and back through the
borehole fluid to an acoustic receiver. Acoustic transmitters
may be piezoelectric crystal or magnetostrictive. Both types of
transmitters convert electrical energy into mechanical energy.
The mechanical energy in the form of an acoustic wave travels
into the surrounding formation and is received by an acoustic
receiver usually of the piezoelectric type. Acoustic waves
traveling in an elastic media are subject to stress and strain.
Most of the interaction of acoustic waves in a rock formation
can be described