Description
: a sonic log measures the interval travel time (delta t) of compression sound waves moving through one foot of a formation (milliseconds/ft). If matrix velocity is known, porosity can be calculated since sound waves travel slower in porous media (travel slower in less dense materials such as fluids). Sonic logs are used for porosity determination, pressure determination in shale, as a correlation log, and a gas detector.
Source :
Vterm research team