HOCIGs and VOCIGs via Two-way Reverse Time Migration

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HOCIGs and VOCIGs via Two-way Reverse Time
Migration
William Symes, Fuchun Gao Rice
University
TRIP Oct 29, 2004
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Outline

• Common image gathers (offset domain)
• 1. Theory
• 2. HOCIGs and VOCIGs--- examples
• Conclusions

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Two-way Reverse Time Migration

• 1. Forward propagation finite difference
  solution to
• acoustic equation by
• where
• impedance
  matrix.
• seismic wave field vector.
• source vector.
•  

Pratt et al.(1998)
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Two-way Reverse Time Migration

• 2. Back-propagation of data
• 3. Horizontal offset image (frequency domain)
• Vertical offset image (frequency domain)
• Common image gathers (time domain)
• where
• recorded wave fields.
  back-propagated waves
• source location.
  image location

( complex conjugate)
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Example 1
No. of source 51 No. of receiver 51 Source
interval 10m Receiver interval10m
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Frequency domain CIGs
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Frequency domain CIGs, tapered
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time domain CIGs
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Example 2
No. of source 101 No. of receiver 101 Source
interval 1.5m Receiver interval1.5m
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Time domain
Frequency domain HOCIGs
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Example 3
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VOCIGs
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Filtered HOCIG
HOCIG