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SOURCE/RECEIVER SPACINGS AND THEIR INFLUENCE ON TOMOGRAMS. Zhiyong Jiang. Geology and Geophysics Department University of Utah. Outline. Motivation Forward Modeling Refraction Tomography Optimal S/R Spacings Conclusions. Goal: Find the Optimal S/R Spacings. Interfaces. 220. - PowerPoint PPT Presentation
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SOURCE/RECEIVER SPACINGS SOURCE/RECEIVER SPACINGS AND THEIR INFLUENCE ON AND THEIR INFLUENCE ON
TOMOGRAMSTOMOGRAMS
Zhiyong JiangZhiyong Jiang
Geology and Geophysics Department Geology and Geophysics Department University of UtahUniversity of Utah
OutlineOutline• MotivationMotivation
• Forward ModelingForward Modeling
• Refraction TomographyRefraction Tomography
• Optimal S/R Spacings Optimal S/R Spacings
• ConclusionsConclusions
220220
1301303290m3290m 3360m3360m
InterfacesInterfacesE
leva
tio
n (
m)
Ele
vati
on
(m
)
X (m)X (m)
Goal:Goal:
Find the Optimal S/R SpacingsFind the Optimal S/R Spacings
0m0m
100m100m0m0m 590m590m
V (m/s)V (m/s)
00
45004500
INCO Velocity ModelINCO Velocity ModelD
epth
(m
)D
epth
(m
)
X (m)X (m)
OutlineOutline• MotivationMotivation
• Forward ModelingForward Modeling
• Refraction TomographyRefraction Tomography
• Optimal S/R Spacings Optimal S/R Spacings
• ConclusionsConclusions
00 590590X (m)X (m)
00
Tim
e (s
)T
ime
(s)
0.30.300 590590X (m)X (m)
Source at (200m, 3.003m)Source at (200m, 3.003m) Source at (400m, 0.427m)Source at (400m, 0.427m)
00 590590X (m)X (m)
00T
ime
(s)
Tim
e (s
)
0.150.15
First Arrivals Auto PickedFirst Arrivals Auto Picked
OutlineOutline• MotivationMotivation
• Forward ModelingForward Modeling
• Refraction TomographyRefraction Tomography
• Optimal S/R Spacings Optimal S/R Spacings
• ConclusionsConclusions
The schedules for dg=4m and ds=8mThe schedules for dg=4m and ds=8m
Smoothing Size (in grid points)Smoothing Size (in grid points) IterationsIterations Grid Size (m)Grid Size (m)
Schedule 1: 48*24Schedule 1: 48*24 1111 0.50.5
Schedule 2: 32*16Schedule 2: 32*16 1111 0.50.5
Schedule 3: 16*8Schedule 3: 16*8 1111 0.50.5
Dynamic SmoothingDynamic Smoothing
dg=4m, ds=8m Schedule 1dg=4m, ds=8m Schedule 1
0m0m
120m120m0m0m 590m590m
V (m/s)V (m/s)
00
45004500
dg=4m, ds=8m Schedule 2dg=4m, ds=8m Schedule 2
0m0m
120m120m0m0m 590m590m
V (m/s)V (m/s)
00
45004500
dg=4m, ds=8m Schedule 3dg=4m, ds=8m Schedule 3
0m0m
120m120m0m0m 590m590m
V (m/s)V (m/s)
00
45004500
dg=4m, ds=8m Schedule 1dg=4m, ds=8m Schedule 1
0m0m
120m120m0m0m 590m590m
Num. of Num. of RaysRays
00
40004000
dg=4m, ds=8m Schedule 2dg=4m, ds=8m Schedule 2
0m0m
120m120m0m0m 590m590m
Num. of Num. of RaysRays
00
40004000
dg=4m, ds=8m Schedule 3dg=4m, ds=8m Schedule 3
0m0m
120m120m0m0m 590m590m
Num. of Num. of RaysRays
00
40004000
Residual vs. Iteration NumberResidual vs. Iteration Number
0000 3535Iteration NumberIteration Number
0.0140.014R
esid
ual
Res
idu
al
Sche 1Sche 1
Sche 2Sche 2Sche 3Sche 3
OutlineOutline• MotivationMotivation
• Forward ModelingForward Modeling
• Refraction TomographyRefraction Tomography
• Optimal S/R Spacings Optimal S/R Spacings
• ConclusionsConclusions
S/R Spacings Tested S/R Spacings Tested
dg (m)dg (m) ds (m)ds (m)
11 2, 42, 4
22 2, 42, 4
44 4, 84, 8
88 8, 168, 16
1212 12, 2412, 24
2424 24, 4824, 48
dg=1m, ds=2mdg=1m, ds=2m
0m0m
120m120m0m0m 590m590m
dg=1m, ds=4mdg=1m, ds=4m
0m0m
120m120m0m0m 590m590m
dg=2m, ds=2mdg=2m, ds=2m
0m0m
120m120m0m0m 590m590m
dg=2m, ds=4mdg=2m, ds=4m
0m0m
120m120m0m0m 590m590m
dg=4m, ds=4mdg=4m, ds=4m
0m0m
120m120m0m0m 590m590m
dg=8m, ds=8mdg=8m, ds=8m
0m0m
120m120m0m0m 590m590m
dg=12m, ds=12mdg=12m, ds=12m
0m0m
120m120m0m0m 590m590m
dg=12m, ds=24mdg=12m, ds=24m
0m0m
120m120m0m0m 590m590m
dg=24m, ds=24mdg=24m, ds=24m
0m0m
120m120m0m0m 590m590m
dg=24m, ds=48mdg=24m, ds=48m
0m0m
120m120m0m0m 590m590m
dg (m)dg (m) ds (m)ds (m)
11 2, 42, 4
22 2, 42, 4
44 4, 84, 8
88 8, 168, 16
1212 12, 12, 2424
2424 24, 4824, 48
High Res.High Res.
Intermediate Res.Intermediate Res.
Poor Res.Poor Res.
S/R Spacings CategorizedS/R Spacings Categorized
dg=2m, ds=2m High Res.dg=2m, ds=2m High Res.
0m0m
120m120m0m0m 590m590m
dg=12m, ds=12 m Interm Res.dg=12m, ds=12 m Interm Res.
0m0m
120m120m0m0m 590m590m
dg=24m, ds=24m Poor Res.dg=24m, ds=24m Poor Res.
0m0m
120m120m0m0m 590m590m
Zoom View, X: 0~200m Zoom View, X: 0~200m
dg=2m, ds=2m High Res.dg=2m, ds=2m High Res.
0m0m
120m120m0m0m 200m200m
dg=12m, ds=12m Interm Res.dg=12m, ds=12m Interm Res.
0m0m
120m120m0m0m 200m200m
dg=24m, ds=24m Poor Res.dg=24m, ds=24m Poor Res.
0m0m
120m120m0m0m 200m200m
Zoom View, X: 200~400m Zoom View, X: 200~400m
dg=2m, ds=2m High Res.dg=2m, ds=2m High Res.
0m0m
120m120m200m200m 400m400m
dg=12m, ds=12m Interm Res.dg=12m, ds=12m Interm Res.
0m0m
120m120m200m200m 400m400m
dg=24m, ds=24m Poor Res.dg=24m, ds=24m Poor Res.
0m0m
120m120m200m200m 400m400m
Zoom View, X 400m~590mZoom View, X 400m~590m
dg=2m, ds=2m High Res.dg=2m, ds=2m High Res.
0m0m
120m120m400m400m 590m590m
dg=12m, ds=12m Interm Res.dg=12m, ds=12m Interm Res.
0m0m
120m120m400m400m 590m590m
dg=24m, ds=24m Poor Res.dg=24m, ds=24m Poor Res.
0m0m
120m120m400m400m 590m590m
OutlineOutline• MotivationMotivation
• Forward ModelingForward Modeling
• Refraction TomographyRefraction Tomography
• Optimal S/R Spacings Optimal S/R Spacings
• ConclusionsConclusions
When ds, dg <= 12m, tomograms When ds, dg <= 12m, tomograms acceptable, resolution high acceptable, resolution high
When ds, dg > 24m, resolution very When ds, dg > 24m, resolution very poor poor
Recommend using ds, dg between Recommend using ds, dg between 1~4 m for good vertical and horizontal 1~4 m for good vertical and horizontal resolutionresolution
ConclusionConclusion
AcknowledgementsAcknowledgements
We thank Utah Tomography and We thank Utah Tomography and Modeling/Migration ConsortiumModeling/Migration Consortium
sponsors for their financial supportsponsors for their financial support