Methodology for attenuating the multiples

The methodology to attenuate the multiples consists of four basic steps: prestack migration of the data with a migration velocity $V_{\mbox{mig}}$ such that $V_{\mbox{mul}} < V_{\mbox{mig}} < V_{\mbox{prim}}$. Estimation of the multiples and the primaries by tapered mute of the SODCIGs to eliminate the primaries and the multiples, respectively. Adjoint migration of the estimated primaries and multiples and adaptive subtraction of the estimated multiples from the original data with the estimated primaries used as a weighting function to restrict the adaptive subtraction to the multiples only. I will now illustrate each of these steps with one gather of the synthetic dataset.

 

sodcigs1
Figure 4 SODCIG migrated with the correct velocity (a) and with 90% of the correct velocity (b).

 

• Prestack depth migration
• Muting the primary and multiple reflections
• Adjoint migration
• Adaptive subtraction