Reverse Time Migration of Multiples for OBS Data

Dongliang ZhangKAUST

Outline

Conclusions

MotivationWider illumination, no footprint artifacts

Numerical ExampleTest on Marmousi model and field data

TheoryReverse time migration of multiples

Outline

Conclusions

MotivationWider illumination, no footprint artifacts

Numerical ExampleTest on Marmousi model and field data

TheoryReverse time migration of multiples

Motivation

Migration Image of Primary

No footprint artifacts Wider illumination

Migration Image of Multiples

reciprocity

Outline

Conclusions

MotivationWider illumination, no footprint artifacts

Numerical ExampleTest on Marmousi model and field data

TheoryReverse time migration of multiples

Primary RTM of Streamer Data

time MultiplePrimary

Multiples RTM of Streamer Data

ReceiverSource

1st- order multiple

2nd- order multiple

……

primary image artifact artifact

1st- order multiple

artifact image artifact

2nd- order multiple

artifact artifact image

……

time MultiplePrimary

Data

Multiples

Multiples RTM of Streamer Data

ReceiverSource

primary 1st- order multiple

2nd- order multiple

……

primary artifact image artifact artifact

1st- order multiple

artifact artifact image artifact

2nd- order multiple

artifact artifact artifact image

……

time MultiplePrimary

Data

Data

Up-going wave

Down-going wave

Combine up-going & down-going waves

Multiples RTM of OBS Data

Up-going wave

Down-going wave

Combine up-going & down-going waves

Multiples RTM of OBS Data

Up-going Wavereciprocity

Up-going wave

Down-going wave

Combine up-going & down-going waves

Multiples RTM of OBS Data

Down-going Wave

reciprocity

Up-going wave

Down-going wave

Combine up-going & down-going waves

Multiples RTM of OBS Data

• Don’t need to separate up-going and down-going wave

• Same procedure as up-going and down-going wave

Illumination of Primary for One Shot

Illumination of Multiples for One Shot

Illumination: Primary vs Multiples

Image of Primary Image of Multiples

Footprint Artifact

Sparse Receivers (Sources)

Outline

Conclusions

MotivationWider illumination, no footprint artifacts

Numerical ExampleTest on Marmousi model and field data

TheoryReverse time migration of multiples

1.5

k

m/s

5.5

True Velocity Model

0 X (km) 9

3.5

Z

(km

)

0

Marmousi Model

Full Data

6

T (

s)

0

0 X (km) 9

Direct Wave & Primary

0 X (km) 9

Multiples

0 X (km) 9

Image of Primary Vs Multiples3.

5

Z (

km)

0

Primary Image with R.I. 50 m Multiples Image with R.I. 50 m

0 X (km) 9

3.5

Z

(km

)

0

0 X (km) 9

Primary Image with R.I. 100 m Multiples Image with R.I. 100 m

Image of Primary Vs Multiples3.

5

Z (

km)

0

Primary Image with R.I. 200 m Multiples Image with R.I. 200 m

0 X (km) 9

3.5

Z

(km

)

0

0 X (km) 9

Primary Image with R.I. 400 m Multiples Image with R.I. 400 m

Field Data

Receivers: 9 Interval: 400m

Sources: 124Interval: 75m

Water Depth: 40m

12

T

(s)

0

0 X (km) 9

Common Receiver Gather

Field Data6

Z (

km

)

0

0 X (km) 9 0 X (km) 9

Image of Primary Image of Multiples

best

Outline

Conclusions

MotivationWider illumination, no footprint artifacts

Numerical ExampleTest on Marmousi model and field data

TheoryReverse time migration of multiples

Conclusions

Wider illumination

No footprint artifact

FWI of OBS data

Thank you!