The quality of the seismic processing depends on the quality of the acquisition. In VSP, the seismic quality depends on both the repetitiveness of the seismic source and the coupling of the VSP tool to the formation. To evaluate the repetitiveness of the seismic source, in time and amplitude, a geophone is located at the surface near the source at a fixed position. The data recorded by the reference geophone are used to do corrections in time and amplitude of the data recorded by the VSP tool.

The video shows the records obtained by the reference geophone and the 3 borehole geophones of the VSP tool. On can notice a time shift on the records obtained by the reference geophone. The time shift is due to a displacement of the seismic source. The time shift will be compensated latter on by a static correction applied to different records . On the horizontal components, we can notice low frequencies due to a poor coupling of the VSP tool at some depth positions. The low frequencies will be filtered latter on by a low cut frequency filter.