Seismic applications > Processing of a 3D shot point

The animation shows the processing sequence of a 3D shot point step by step:

  • Step 1: Description of the acquisition spread. It is a cross spread composed of 48 traces. The source is situated in the middle of the recording spread with a lateral offset of 45m

  • Step 2: Display of the shot point before and after band pass filtering. In the upper part, we can see the refracted wave, the high frequency air wave and the low frequency surface wave. In the lower part, after filtering the air waves and surface waves are attenuated.

  • Step 3: Display of the shot point after amplitude recovery and band pass filtering: one can see refracted waves in first arrivals and guess a reflected wave after 0.1s.

  • Step 4: Display of the shot point after amplitude recovery, band pass filtering and deconvolution. The deconvolution increases the vertical resolution and facilitates the wave separation.

  • Step 5: Extraction of refracted waves by SVD filter.

  • Step 6: Computation of the first residual section: in the F_K diagram one can see events with wavenumbers close to 0 and frequencies ranging between 50 Hz up to 200 Hz. One can also see events with low frequencies and wavenumber ranging between -0.1 and 0.1 c/m.

  • Step 7: Extraction of seismic waves with low apparent velocities by F-K filter.

  • Step 8: Computation of the second residual section: one can mainly see reflected waves.

  • Step 9: Reflected waves after static corrections

  • Step 10: NMO correction with time variant velocity model. The reflected waves are flattened. We can see seismic horizons between 0.04 and 0.12 s.

  • Step 11: Time variant velocity model used for the NMO correction

  • Step 12: Time to depth conversion of the seismic section. On the upper of the figure, we have the depth versus time law. On the seismic section, we can see a continuous layer above 60 m. The layers below 60 m are situated in the bed rock.