The sonic tool uses the parameters of sound transmission in the rock formations. An acoustic source produces a pressure pulse that is transmitted to the fluid in the hole and subsequently to the rock formations.
The receivers record the arrival of the different types of waves, which, allow to calculate the inverse of the propagation velocity of the compression waves (P), shear waves(S) and Stoneley waves(St). The instrument is operative in boreholes filled by a fluid and it needs to be centralizated.
♦ Fractures and cavities identification;
♦ Determination of Vp and Vs of the rock formations in open holes;
♦ Information on lithology, porosity and fracturing state of the rock formations;
♦ Calculation of the elastic properties of the rocks;
♦ Cementation quality check of metal casing and PVC pipes (cement bond log CBL).