A record of a well-logging measurement of one or more specific characteristics of acoustic waves propagated in and around the liquid-filled wellbore.
(1) The interval transit time, usually of the compressional wave, is recorded on such logs as the sonic log, continuous velocity logs, and borehole compensated sonic and Acoustilogs.
(2) The amplitude of part of the propagated acoustic wave, such as the compressional wave or shear wave is the measurement recorded on other well logs. These are the amplitude log, cement bond log, and fracture logs.
(3) The acoustic wave train of the propagated acoustic wave is displayed in the amplitude-time mode on full wave train logs such as signature logs or character logs; whereas the wave train is shown in the intensity modulated-time mode on variable density logs, variable intensity logs, 3-D Velocity Logs, or Micro-Seismogram Logs.
(4) Includes logs resulting from the measurements of travel time and amplitude of reflected acoustic energy. Tools making such measurements are the borehole televiewer and sonar caliper.
(5) Also includes logs produced by devices which detect and measure the amplitude of sound waves in the audible frequency range. Audible sound might emanate from liquid or gas movements in the wellbore environment. Tools developed to make such measurements are used in audio or noise logging techniques.