Transcript Amplitude-preserved common image gathers by wave

Angle-domain
common-image gathers
Paul Sava*
Sergey Fomel
Stanford University
UT Austin (UC Berkeley)
paul@sep.stanford.edu
Common Image Gathers
• Representations of the seismic events
sorted by their location in the subsurface
• Image domain
– offset-domain
– angle-domain
• Classes of methods
– Kirchhoff
– Wave-equation
• S-G migration
• shot-profile migration
paul@sep.stanford.edu
Agenda
Definitions
Common-image gathers
Offset vs. angle
Computational space
ADCIG methodology
Examples
paul@sep.stanford.edu
Offset-Domain Common Image Gathers
Kirchhoff
Wave-equation
h
h
flat events
z
focused events
z
paul@sep.stanford.edu
Angle-Domain Common Image Gathers
Kirchhoff
Wave-equation
g
g
flat events
z
flat events
z
paul@sep.stanford.edu
Example
paul@sep.stanford.edu
Agenda
Definitions
Common-image gathers
Offset vs. angle
Computational space
ADCIG methodology
Examples
paul@sep.stanford.edu
Reflection scheme
Source
Receiver
V(x,y,z)
2h
g g
a
g g
v
paul@sep.stanford.edu
Wave-equation ADCIG methods
IMAGE space
z
tan g  
h
DATA space
x-domain
(slant-stack)
Reflection angle (g)
kh
tan g  
kz
t
ph 
h
Offset ray-parameter (ph)
k-domain
(RTT)
ph 
kh

paul@sep.stanford.edu
Agenda
Definitions
Common-image gathers
Offset vs. angle
Computational space
ADCIG methodology
Examples
paul@sep.stanford.edu
Wave-equation CIGs: example
ODCIG
ADCIG
paul@sep.stanford.edu
ADCIG: g vs. ph
paul@sep.stanford.edu
Summary
• CIG domains
– offset or angle
• CIG concepts
– flatness: Kirchhoff
– focusing: wave-equation
• Wave-equation ADCIG
– data space
– image space
paul@sep.stanford.edu