hocigs and vocigs via two-way reverse time migration
DESCRIPTION
HOCIGs and VOCIGs via Two-way Reverse Time Migration. William Symes, Fuchun Gao Rice University. TRIP Oct 29, 2004. Outline. Common image gathers (offset domain) 1. Theory 2. HOCIGs and VOCIGs--- examples Conclusions. Two-way Reverse Time Migration. - PowerPoint PPT PresentationTRANSCRIPT
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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.
MωCiωKS 2
fuS s
su
f
,fSus1
Pratt et al.(1998)
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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
*1dSur
),,,(),,,(),,,,( zhxxuzhxxuhzxxI srsss
d
sx
Two-way Reverse Time Migration
ddxhzxxIhzxI ss ),,,,(),,(
),,,(),,,(),,,,( hzxxuhzxxuhzxxI srsss
zx,
ru
( : complex conjugate)*
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Example 1
No. of source = 51
No. of receiver = 51
Source interval =10m
Receiver interval=10m
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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 interval=1.5m
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Time domainFrequency domain HOCIGs
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Example 3
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VOCIGs
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Filtered HOCIGHOCIG