PP results

Figure  shows the migration result. Figure  shows three angle gathers. Observe the residual moveout in these angle gathers. This indicates errors in the velocity model.

 

ppmiga Figure 1 PP migration result with the original P-velocity model

 

ppmigb
Figure 2 Three angle domain common image gathers for the migration result of Figure . They corresponds, from left to right, to a lateral position of 2500m, 4500m and 6500m. Observe the residual curvature.

I perform Stolt residual migration Sava (1999) over this migration result. There is not a single value of $\rho_p$ that fixes the whole section. Figure  shows the same three angle domain common image gathers, as in Figure . Moreover, each angle domain common image gather corresponds to a different value of $\rho_p$, from left to right, $\rho_p=0.98$ $\rho_p=0.99$ and $\rho_p=1.02$. Note how different events correct better for different $\rho_p$ values.

 

ppsrm2
Figure 3 Angle domain common image gathers after Stolt residual migration. They corresponds to the same position as the angle gathers in Figure . Moreover, from left to right they also correspond to $\rho_p=0.98$ $\rho_p=0.99$ and $\rho_p=1.02$

By updating the velocity model with different $\rho_p$ values at different depths and lateral positions, I perform a new migration. Figure  shows this final migration result. Figure  shows again the same different angle domain common image gathers for the migration result of Figure .

 

finalpp Figure 4 Migration result after updating the P velocity model with different values of $\rho_p$ at different depth and lateral locations.

 

finalcag
Figure 5 Angle domain common image gathers for the migration result of Figure  at the same position of Figure .