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Velocity analysis and residual statics strategy

A problem encountered in residual statics estimation is the coupling of velocity and statics. Changing the medium wavelength statics (0.5 to 3 spread length) will change the medium wavelength stacking velocity. The classic approach to this problem is to repeat the velocity analysis and residual static estimation sequence. Incorporating rapid lateral variation in the initial stacking velocity will prevent the medium wavelength estimation by residual statics. The undesirable rapid velocity variation is locked into the final velocity field. I used the strategy described on page 236 of Mike Cox' statics book (Cox, 1999). I ran velocity analysis and statics twice. On the first iteration, I used single function velocity function for moveout before residual static estimation. If the line was longer I might have run a coarsely sampled set of velocity analyzes. After the first pass of residual statics, I ran velocity analysis every 48 CDPs (2640 ft or 0.5 spreadlength). I did not notice improvement when I compared the stack with the first pass of residual statics and the velocity field from the 48 CDP velocity analysis with the results after two passes of residual statics. The next sections step through the velocity analysis and residual static processes.


next up previous [pdf]

Next: First Pass Velocity analysis Up: Schleicher: Alaska Previous: cdp sort and mute

2012-01-29