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X (km). X (km). 10. 10. 8. 8. 6. 6. 4. 4. 6. 6. Y (km). Y (km). 8. 8. Comparison of Poststack MD Depth Slices. Kirchhoff Image. MD Image. 4. 4. 6. 6. 8. 8. 10. 10. 1. 1. Depth (km). Depth (km). 4. 4. Comparison of Prestack Migration and MD Images. X (km).

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Comparison of poststack md depth slices

  • X (km)

  • 10

  • 10

  • 8

  • 8

  • 6

  • 6

4

4

  • 6

  • 6

  • Y (km)

  • Y (km)

  • 8

  • 8

Comparison of Poststack MD Depth Slices

  • Kirchhoff Image

  • MD Image


Comparison of prestack migration and md images

  • 4

  • 6

  • 6

  • 8

  • 8

  • 10

  • 10

  • 1

  • 1

  • Depth (km)

  • Depth (km)

  • 4

  • 4

Comparison of Prestack Migration and MD Images

  • X (km)

  • Prestack Kirchhoff Migration Image of

  • a North Sea Data Set

  • X (km)

  • MD Image


Prestack migration deconvolution
Prestack Migration Deconvolution

Jianxing Hu

University of Utah


Outline
Outline

  • Methodology

  • Theory and implementation

  • Numerical Tests

  • Synthetic and field data tests

  • Conclusions


Modeling and migration
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
Reflectivity Modulated by Migration Green’s Function

Model Space


Migration deconvolution
Migration Deconvolution

Model Space

Model

Space

--- reference position of migration Green’s function


Methodology

Traveltime Table

Migration

Green’s function

Methodology

Calculate migration Green’s function

Recording geometry &

migrated image dimension

+

Velocity Model


Methodology1

Apply migration deconvolution

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)

Methodology

Deconvolved Image

Migration Image

5

Pseudo-Convolution


Difference between poststack md and prestack md

Recording Geometry &

migrated image dimension

+

Prestackmigration

Green’s function

Difference between Poststack MD and Prestack MD

Zero-offset trace location &

migrated image dimension

+

Velocity Model

Traveltime Table

Poststackmigration

Green’s function


Md implementation
MD Implementation

Entire Migrated

Image Cube

Division Parts

Image Layers

Y

X

Z


Md scheme for marine survey
MD Scheme for Marine Survey

Partitioned

Image Cube

Smaller Traveltime Table

Computing Nodes


Md scheme for 3 d land survey
MD Scheme for 3-D Land Survey

Partitioned

Image Cube

Smaller Traveltime Table

Computing Nodes

Problem: Lose Far-Offset Traces


Lateral velocity variation

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 Variation


Outline1
Outline

  • Methodology

  • Numerical Tests

  • Conclusions


Numerical tests
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


Recording Geometry

5 X 5 Sources; 21 X 21 Receivers

Wavelet frequency 50 Hz

(0, 1km)

(0, 0)

(1km, 1km)

(1km, 0)

Point scatterer




Numerical tests1
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


Recording Geometry

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


Meandering River Model

X (m)

0

1000

0

Depth (m)

1000


Kirchhoff migration image

X (m)

0

1000

0

Depth (m)

1000

Kirchhoff Migration Image


Md image

X (m)

0

1000

0

Depth (m)

1000

MD Image


Numerical tests2
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)


Zoom View of KM and MD

3

3

7

7

X (km)

X (km)

2

2

Depth (km)

Depth (km)

3

3

4

4

Prestack KM

Prestack MD


Numerical tests3
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


Husky prestack migration image

X(km)

10

0

5

0

2

Depth (km)

6

Husky Prestack Migration Image

4


Velocity model for husky data

X(km)

10

0

5

0

2

Depth (km)

6

Velocity Model for Husky Data

7000

Velocity (m/s)

3200


Md with 3 reference positions

X(km)

10

0

5

0

2

Depth (km)

6

MD with 3 reference positions


Md with 20 reference positions

X(km)

10

0

5

0

2

Depth (km)

6

MD with 20 reference positions


KM Image

MD Image

3 references

MD Image

20 references


Md with 20 reference positions1

X(km)

10

0

5

0

2

Depth (km)

6

MD with 20 reference positions

A


5

9

X(km)

1

KM

Depth (km)

3

5

X(km)

9

1

MD

Depth (km)

3


Md with 20 reference positions2

X(km)

10

0

5

0

2

Depth (km)

6

MD with 20 reference positions

B


11

14

X(km)

1

KM

Depth (km)

3

11

X(km)

14

1

MD

Depth (km)

3


Md with 20 reference positions3

X(km)

10

0

5

0

2

Depth (km)

6

MD with 20 reference positions

C


10

X(km)

14

2

KM

Depth (km)

5

10

X(km)

14

2

MD

Depth (km)

5


10

X(km)

14

2

KM

Depth (km)

Whitening &

Bandpass

5

10

X(km)

14

2

MD

Depth (km)

5


Numerical tests4
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



Y (km)

5

8

0

0

Depth (km)

2

2

4

4

Y (km)

5

8

KM Inline (97,Y) Section

MD Inline (97,Y) Section


X (km)

X (km)

8

8

11

11

0

0

2

2

4

4

Depth (km)

KM Crossline (X,97) Section

MD Crossline (X,97) Section


Depth Slices

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 tests5
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


Velocity model for west texas data
Velocity Model for West Texas Data

X (kft)

0

15

0

20

Velocity (kft/s)

Depth(kft)

14

6


West texas data
West Texas Data

X (kft)

0

10

4

8

Depth (kft)

KM Inline

Section (X,93)

12

16


West texas data1

X (kft)

0

10

4

8

Depth (kft)

12

16

West Texas Data

KM Crossline

Section (93,Y)


KM

MD

X(kft)

0

3

4

4

Depth (kft)

6

6

8

8

X(kft)

0

3


KM

MD

X(kft)

X(kft)

4

4

2

2

4

Depth (kft)

6

8

4

6

8


Outline2
Outline

  • Methodology

  • Numerical Tests

  • Conclusions


Conclusions

More work is needed to remedy

the problems in MD for 3-D

land prestack data

Standard post-migration

processing procedure ?

Conclusions

Works well on 2-D land and 3-D

synthetic marine prestack data


Acknowledgement
Acknowledgement

  • Thank 1999 UTAM sponsors for their financial support


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