Difference between revisions of "Common-offset migration of DMO-corrected data"

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This technique for [[migration]] [[velocity analysis]] is the basis for the most common sequence used for prestack time [[migration]] ([[prestack time migration]]). A flowchart for the method is shown in Figure 5.4-4.
 
This technique for [[migration]] [[velocity analysis]] is the basis for the most common sequence used for prestack time [[migration]] ([[prestack time migration]]). A flowchart for the method is shown in Figure 5.4-4.
  
[[file:ch05_fig4-4.png|thumb|{{figure number|5.4-4}} A flowchart of an algorithm for common-offset migration of DMO-corrected data.]]
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[[file:ch05_fig4-4.png|left|thumb|{{figure number|5.4-4}} A flowchart of an algorithm for common-offset migration of DMO-corrected data.]]
  
 
# Starting with prestack data ''P''(''y'', ''h'', ''t'') in coordinates of midpoint ''y'', offset ''h'', and two-way event time ''t'' in the unmigrated position, apply NMO correction using an initial velocity field with minimal dip effect.
 
# Starting with prestack data ''P''(''y'', ''h'', ''t'') in coordinates of midpoint ''y'', offset ''h'', and two-way event time ''t'' in the unmigrated position, apply NMO correction using an initial velocity field with minimal dip effect.

Latest revision as of 14:26, 25 September 2014

Seismic Data Analysis
Seismic-data-analysis.jpg
Series Investigations in Geophysics
Author Öz Yilmaz
DOI http://dx.doi.org/10.1190/1.9781560801580
ISBN ISBN 978-1-56080-094-1
Store SEG Online Store


This technique for migration velocity analysis is the basis for the most common sequence used for prestack time migration (prestack time migration). A flowchart for the method is shown in Figure 5.4-4.

Figure 5.4-4  A flowchart of an algorithm for common-offset migration of DMO-corrected data.
  1. Starting with prestack data P(y, h, t) in coordinates of midpoint y, offset h, and two-way event time t in the unmigrated position, apply NMO correction using an initial velocity field with minimal dip effect.
  2. Sort the normal-moveout corrected data P(y, h, tn) to common-offset sections P(y, tn; h).
  3. To each common-offset section P(y, tn; h), apply DMO correction P(y, τ0; h).
  4. Migrate each of the common-offset sections using a zero-offset migration algorithm (migration) and the velocity field based on the flat-event velocity picks from step (a).
  5. Sort the migrated common-offset data P(y, τ; h) back to CMP gathers P(y, h, τ) and apply inverse NMO correction using the flat-event velocities from step (a).
  6. Perform velocity analysis at frequent intervals as needed to derive an optimum velocity field which is used for the subsequent migration of the data.

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Common-offset migration of DMO-corrected data
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