The video shows the processing sequence applied to VSP data recorded with a hydrophone.

The VSP shows a strong attenuation of the down going wave field which can be compensated by a function of normalization in depth. After normalization, we can notice that the first arrival which is the down going P wave is strongly attenuated at 60 m depth. At that depth, the P-wave is partly converted to a down going Stoneley wave which is reflected at the bottom of the well. The down going Stoneley mode can be extracted by a velocity filter, the velocity being the apparent velocity of the Stoneley wave. A narrow band wave number filter applied after velocity correction is equivalent to a velocity filter in the f, k domain. To determine the value of the velocity, a scan in velocity is down. For a given value of velocity, the Stoneley wave is extracted and the residue, difference between the initial VSP data and the estimated down going Stoneley wave, is computed. The selected velocity is the velocity for which the foot print of the the Stoneley wave is minimum in the residue. The apparent velocity of the Stoneley mode is of the order of 1300 meters per second. The same procedure is applied to extract the up going Stoneley wave, but the apparent velocity is negative. The down going and up going Stoneley wave fields can be added to create the total Stoneley wave field. A second residue, difference between the initial VSP data and the total Stoneley wave field, is computed. It mainly shows a weak down going P wave field and noise.