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Comparison of Poststack MD Depth SlicesPowerPoint Presentation

Comparison of Poststack MD Depth Slices

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Presentation Transcript

Numerical Tests

- X (km)

- 10

- 10

- 8

- 8

- 6

- 6

4

4

- 6

- 6

- Y (km)

- Y (km)

- 8

- 8

- Kirchhoff Image

- MD Image

- 4

- 6

- 6

- 8

- 8

- 10

- 10

- 1

- 1

- Depth (km)

- Depth (km)

- 4

- 4

- X (km)

- Prestack Kirchhoff Migration Image of
- a North Sea Data Set

- X (km)

- MD Image

Outline

- Methodology
- Theory and implementation
- Numerical Tests
- Synthetic and field data tests
- Conclusions

Modeling and Migration

Forward Modeling:

Model Space

Green’s Function

Reflectivity

Wavelet

Seismic data

Migration:

Data Space

Migrated Image

Seismic Data

Model Space

Where:

Data Space

Denote

as the migration Green’s Function

Reflectivity Modulated by Migration Green’s Function

Model Space

Migration Deconvolution

Model Space

Model

Space

--- reference position of migration Green’s function

Migration

Green’s function

MethodologyCalculate migration Green’s function

Recording geometry &

migrated image dimension

+

Velocity Model

filter to the stacked prestack

migration image

RTM

RTM

6

6

5

5

1

1

2

2

Depth (km)

Depth (km)

3

3

Offset(km)

Offset(km)

MethodologyDeconvolved Image

Migration Image

5

Pseudo-Convolution

migrated image dimension

+

Prestackmigration

Green’s function

Difference between Poststack MD and Prestack MDZero-offset trace location &

migrated image dimension

+

Velocity Model

Traveltime Table

Poststackmigration

Green’s function

MD Scheme for 3-D Land Survey

Partitioned

Image Cube

Smaller Traveltime Table

Computing Nodes

Problem: Lose Far-Offset Traces

Subdivide the migration image area and use multi-

reference migration Green’s function to account for

lateral velocity variation and far-field artifacts

Multi-Reference migration Green’s function

Lateral Velocity VariationOutline

- Methodology
- Numerical Tests
- Conclusions

Numerical Tests

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set (Canadian Foothills)
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

5 X 5 Sources; 21 X 21 Receivers

Wavelet frequency 50 Hz

(0, 1km)

(0, 0)

(1km, 1km)

(1km, 0)

Point scatterer

Numerical Tests

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set (Canadian Foothills)
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

5 X 5 Sources; 21 X 21 Receivers

Wavelet frequency 50 Hz

(0, 1 km)

(0, 0)

(1 km,1 km)

(1 km, 0)

A river channel

Numerical Tests

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set (Canadian Foothills)
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

20 km

0 km

4 km

- Prestack Migration Image

X(km)

0 km

- 20 km

0 km

Depth (km)

4 km

- Deconvolved Migration Image

X(km)

Depth (km)

3

3

7

7

X (km)

X (km)

2

2

Depth (km)

Depth (km)

3

3

4

4

Prestack KM

Prestack MD

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set (Canadian Foothills)
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

Numerical Tests

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

X (km)

8

8

11

11

0

0

2

2

4

4

Depth (km)

KM Crossline (X,97) Section

MD Crossline (X,97) Section

Y (km)

Y (km)

5

5

8

8

8

8

X (km)

X (km)

11

11

KM

MD

Y (km)

5

8

Y (km)

5

8

8

8

600 m

X (km)

X (km)

11

11

800 m

Numerical Tests

- 3-D point scatterer model
- 3-D meandering stream model
- 2-D SEG/EAGE overthrust model
- 2-D Husky data set
- 3-D SEG/EAGE salt model
- 3-D West Texas data set

Outline

- Methodology
- Numerical Tests
- Conclusions

the problems in MD for 3-D

land prestack data

Standard post-migration

processing procedure ?

ConclusionsWorks well on 2-D land and 3-D

synthetic marine prestack data

Acknowledgement

- Thank 1999 UTAM sponsors for their financial support

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