Transcript Wavelet Extraction using Interferometry

Wavelet Extraction using
Seismic Interferometry
C. Boonyasiriwat and S. Dong
November 15, 2007
Outline


Theory
Numerical Results

Synthetic Data Test



Field Data Test



10-Layer Model
Model with Mapleton Topography
Mapleton Data
Conclusion
Future Work



Field Data Test on North Sea Data
VSP -> VSP Case
Statics Estimation for SSP -> SSP Case
Theory

SSP-to-SSP Transform
X
A
B
Theory

SSP-to-SSP Transform
X
A

B
Theory

SSP-to-SSP Transform
X
A
B
Theory

SSP-to-SSP Transform
X
A

B
Theory

SSP-to-SSP Transform
X
A
B
Theory

Virtual CSG
Pvirt ( ) | S ( ) | G( )

Real CSG
Preal ( )  S ( )G( )

Extracted Wavelet
2
 Pvirt ( ) P ( ) 
S ( )  

*
 Preal ( ) Preal ( )   
*
real
*
Numerical Results

Synthetic Data Test
10-Layer Model
 Model with Mapleton Topography


Field Data Test

Mapleton Data
10-Layer Model
Original CSG vs. Virtual CSG
Virtual Shot Gather
0
0
0.2
0.2
0.4
0.4
0.6
0.6
Time (seconds)
Time (seconds)
Original Shot Gather
0.8
1
1.2
0.8
1
1.2
1.4
1.4
1.6
1.6
1.8
1.8
2
0
1000
2000
Offset (meter)
2
0
1000
2000
Offset (meter)
True Source vs. Extracted Source
True Source Signature versus Extracted Source Signature
1
Extracted Source
True Source
0.8
0.6
Amplitude
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0
0.1
0.2
0.3
Time (seconds)
0.4
0.5
Model with Mapleton Topography
Original CSG vs. Virtual CSG
Virtual Shot Gather
0
0
0.05
0.05
0.1
0.1
Time (seconds)
Time (seconds)
Original Shot Gather
0.15
0.2
0.25
0.15
0.2
0.25
0
10
Offset (meter)
20
0
10
Offset (meter)
20
True Source vs. Extracted Source
True Source Signature versus Extracted Source Signature
1
Extracted Source
True Source
0.8
0.6
Amplitude
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0
0.01
0.02
0.03
0.04
Time (seconds)
0.05
0.06
0.07
Mapleton Data


Surface wave has relatively lower frequency than
the P-wave signal.
The extracted wavelet has low peak frequency
and narrower bandwidth compared to those of
the data.

The strong surface wave affected the extracted
wavelet.
Conclusion


Seismic interferometry (SSP -> SSP case) can be
utilized to extract a source signature from a data
set itself without velocity information.
Further test will be done on the North Sea data.
Future Work


Wavelet extraction in VSP -> VSP case.
Statics estimation using SSP -> SSP transform.