1. Direct detection of near-surface faults by migration of back-scattered surface waves
Han Yu, Bowen Guo*, Sherif Hanafy, Fan-Chi Lin**, Gerard T. Schuster
King Abdullah University of Science and Technology
Center for Subsurface Imaging and Fluid Modeling (CSIM)
** The University of Utah
October 29, 2014

2. Outline Motivation: Near-surface fault detection
Methodology : Migrate back-scattered surface waves
Numerical results: Synthetic and field data
Future Work

3. Outline Motivation: Near-surface fault detection
Methodology : Migrate back-scattered surface waves
Numerical results: Synthetic and Aqaba data
Future Work

4. Motivation: detect near-surface fault by migrating surface waves
2.8 km/s
Depth (m)
0.3 km/s 50
300
Distance (m)
P Wave Velocity Tomogram

5. Outline Motivation: Near-surface fault detection
Methodology : Migrate back-scattered surface waves
Numerical results: Synthetic and Aqaba data
Future Work

6. Methodology: migrate back-scattered surface wave
Why surface waves?
Strong amplitude.
Traveling near-surface.
No need for surface
wave velocity for
migration for dense
source and receiver
distribution

7. Methodology: migrate back-scattered surface wave
Src: s
Rec: g
xf: Fault Position
Back-scattered Surface Waves
Fault
Source and Receiver Positions
Geometrical spreading from the scatter location to receiver
Back-scattered Reflection Coefficient

8. Methodology: migrate back-scattered surface wave
s: source
g: receiver
x: Trial Image Point
Fault
Direct surface wave from s to x
Direct surface wave from x to g
Back scattered surface wave
De-dispersion term

9. Methodology: migrate back-scattered surface wave
No need for surface wave velocity
s: source
g: receiver
x: Trial Image Point
Fault

10. Work flow
Step 0: mute body wave Step 1: filter out back-scattered surface wave Step 2: migrate back-scattered surface wave

11. Outline Motivation: Near-surface fault detection
Methodology : Migrate back-scattered surface waves
Numerical results: Synthetic and Aqaba data
Future Work

12. Synthetic Example (Guo et al., 2014)

13. Field Example 3 4 1 2 a). Common Shot Gather #20
c). Prestack Migration Images
Shot Number
0.8 1
Not very clear back-scattered surface wave
Time (s)
120
0.0
297
297
Stacked Migration Image
b). F-K Filtered Shot Gather #20
0.8
d). Tomogram and COG
Depth (m)
2.7 km/s
Time (s) 3 4 1 2 50
0.3 km/s
Time (s)
0.0
297
0.08
X (m)
297

14. Outline Motivation: Near-surface fault detection
Methodology : Migrate back-scattered surface waves
Numerical results: Synthetic and Aqaba data
Future Work

15. Future Work More robust way to filter out back-scattered surface wave
Extension to 3D case

16. Thanks to the 2014 sponsors of the CSIM consortium
Thanks to the 2014 sponsors of the CSIM consortium. Thanks to the HPC center of King Abdullah University of Science and technology .
Thank you !