Wavelet Extraction Wavelet Extraction usingusing

Seismic Seismic InterferometryInterferometry

C. Boonyasiriwat and S. DongC. Boonyasiriwat and S. DongNovember 15, 2007November 15, 2007

OutlineOutline TheoryTheory Numerical ResultsNumerical Results

Synthetic Data TestSynthetic Data Test 10-Layer Model10-Layer Model Model with Mapleton TopographyModel with Mapleton Topography

Field Data TestField Data Test Mapleton DataMapleton Data

ConclusionConclusion Future WorkFuture Work

Field Data Test on North Sea DataField Data Test on North Sea Data VSP -> VSP CaseVSP -> VSP Case Statics Estimation for SSP -> SSP CaseStatics Estimation for SSP -> SSP Case

TheoryTheory

SSP-to-SSP TransformSSP-to-SSP Transform

X A B

TheoryTheory

SSP-to-SSP TransformSSP-to-SSP Transform

X A B

TheoryTheory

SSP-to-SSP TransformSSP-to-SSP Transform

X A B

TheoryTheory

SSP-to-SSP TransformSSP-to-SSP Transform

X A B

TheoryTheory

SSP-to-SSP TransformSSP-to-SSP Transform

X A B

TheoryTheory

Virtual CSGVirtual CSG )(|)(|)( 2 GSPvirt

Real CSGReal CSG )()()( GSPreal

Extracted WaveletExtracted Wavelet

*

*

*

)()(

)()()(

realreal

realvirt

PP

PPS

Numerical ResultsNumerical Results

Synthetic Data TestSynthetic Data Test 10-Layer Model10-Layer Model Model with Mapleton TopographyModel with Mapleton Topography

Field Data TestField Data Test Mapleton DataMapleton Data

10-Layer Model10-Layer Model

Original CSG vs. Virtual Original CSG vs. Virtual CSGCSG

Offset (meter)

Tim

e (

seco

nd

s)Original Shot Gather

0 1000 2000

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Offset (meter)

Tim

e (

seco

nd

s)

Virtual Shot Gather

0 1000 2000

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

True Source vs. True Source vs. Extracted SourceExtracted Source

0 0.1 0.2 0.3 0.4 0.5-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (seconds)

Am

plit

ud

eTrue Source Signature versus Extracted Source Signature

Extracted SourceTrue Source

Model with Mapleton Model with Mapleton TopographyTopography

Original CSG vs. Virtual Original CSG vs. Virtual CSGCSG

Offset (meter)

Tim

e (

seco

nd

s)Original Shot Gather

0 10 20

0

0.05

0.1

0.15

0.2

0.25

Offset (meter)

Tim

e (

seco

nd

s)

Virtual Shot Gather

0 10 20

0

0.05

0.1

0.15

0.2

0.25

True Source vs. True Source vs. Extracted SourceExtracted Source

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (seconds)

Am

plit

ud

eTrue Source Signature versus Extracted Source Signature

Extracted SourceTrue Source

Mapleton DataMapleton Data Surface wave has relatively lower Surface wave has relatively lower

frequency than the P-wave signal.frequency than the P-wave signal. The extracted wavelet has low peak The extracted wavelet has low peak

frequency and narrower bandwidth frequency and narrower bandwidth compared to those of the data.compared to those of the data. The strong surface wave affected the The strong surface wave affected the

extracted wavelet.extracted wavelet.

ConclusionConclusion Seismic interferometry (SSP -> SSP Seismic interferometry (SSP -> SSP

case) can be utilized to extract a case) can be utilized to extract a source signature from a data set source signature from a data set itself without velocity information.itself without velocity information.

Further test will be done on the Further test will be done on the North Sea data.North Sea data.

Future WorkFuture Work Wavelet extraction in VSP -> VSP Wavelet extraction in VSP -> VSP

case.case. Statics estimation using SSP -> SSP Statics estimation using SSP -> SSP

transform.transform.