Transcript No Slide Title

Migration Accuracy vs $$$
Full-Wave
Ray-Beam
Kirchhoff
Wavefront
Beam
Phase-Shift
Fewer Approxs.
Multiple Arrival
Anti-aliasing
Expense
Most Kirchhoff Tricks for Kirchhoff
Generalized
Kirch.
Migration
Reverse
Time
Migration
Migration
can be
Implemented
for RTM
w ,r,s
Calc.
Green’s
Func.
By FD
solves
Expensive
to store
Calc.
Green’s
Func.
By FD solves
Trial image pt x
G(s|x)* [G(x|r)* d(r) ]=
m(x)
Generalized
= dot
dot product
product data
data with
with hyperbola
hyperbola
Generalized Kirchhoff
Kirchhoff Kernel
Kernel =
Direct wave
T=0
T=0
s
Backpropagated
traces
r
x
r
RTM can now enjoy:
Anti-aliasing filter
Obliquity factor
Angle Gathers
UD Separation
Decomplexify back&forward
felds according 2 taste
Etc. etc.
Gen.
Kirch.
Mig.Migration
Workflow
Reverse
Time
Step 1: Compute G(s|x) by FD for s and x
Step 2: Compute G(x|r) by FD for r and x
*]d(r) =
*
[
G(s|x)
G(x|r)
w ,r,s
Step 3:
m(x)
Standard RTM vs Filtered GKM
Min Zhou (2003)
Summary
• RTM = Gen. Diffraction Stack Migration
• Kirchhoff-like Filtering of Focusing Kernels
G(s|x) G(x|r)
• Expensive Storage-More Suited for Target RTM
• Decomplexify back and forward fields
as needed
• Memory Cost is Issue