Overview of Utah Tomography and Modeling/Migration (UTAM)

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Overview of Utah Tomography and Modeling/Migration(UTAM)

Chaiwoot B., T. Crosby, G. Jiang, R. He, G. Schuster,

J. Sheng, J. Yu, M. Zhou and Xiang Xiao

2004 UTAM Consortium

($24 K/year)

Aramco

BP-Amoco

BGP

Geotomo

Chevron-Texaco

Conoco-Phillips

IMP

INCO

Sisimage

Unocal

Veritas

Western-Geco

UTAM

- Started 1988

- Goal: Innovative Imaging/Modeling

- 10-18 sponsors/year

- $24,000/year membership

- Benefits: Yearly meeting: Feb. 3-4

Annual+midyr Report

Software

Interferometric Imaging below Salt

And Overburden

Jianhua Yu, Min Zhou

Gerard T. Schuster

University of Utah

Outline

Motivation

Interferometric Imaging

Synthetic Data

Conclusions

Outline

Motivation

Interferometric Imaging

Synthetic & Field Data

Conclusions

Salt v(x,y,z) not known

Static errors

?

Problems with VSP or CDP Salt Imaging Quality?

Outline

Motivation

Interferometric Imaging

Synthetic & Field Data

Conclusions

How do you remove kinematic effects of propagating

through unintersting parts of medium?

Uninteresting Part of Medium

Pick Direct Arrival Time T and shift all

Traces by T

T

M

{

M

M

M

T

M

{

Shifting Traces Removes Kinematic Effects

Of Propagating through Uninteresting Parts of Medium

M

Shifting Traces Removes Kinematic Effects

Of Propagating through Uninteresting Parts of Medium

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Shifting Traces Removes Kinematic Effects

Of Propagating through Uninteresting Parts of Medium.

.

Source Moved to Depth

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Can replace time-shifted traces by crosscorrelograms

M

Eliminates source statics and uninteresting parts of the medium.

Lower source to be near target.

Eliminates source+rec statics and uninteresting parts of the medium.

Lower source+rec. to be near target.

Reference layer

Outline

Motivation

Interferometric Imaging

Synthetic CDP Data & Field Data

Conclusions

X (km)

3

0

0

Depth (km)

Shots: 280

Shot interval: 10 m

Receivers: 300

Receiver interval: 10 m

Temporal interval:1ms

1.8

Salt model

X (km)

0

3

0

Depth (km)

1.8

True velocity model

X (km)

0

3

0

Pick Traveltime

Subsalt Reference

Reflection

Time (s)

3

CSG 100

X (km)

0

3

0

Depth (km)

1.8

Kirmig with inaccurate salt dome boundary

X (km)

0

3

0

Depth (km)

1.8

RT migration with inaccurate salt dome boundary

X (km)

X (km)

X (km)

3

3

3

0

0

0

0

Depth (km)

1.8

Standard mig

Correct velocity

Standard mig

Incorrect velocity

RT mig

Outline

Motivation

Interferometric Imaging

Synthetic HSP Data & Field Data

Conclusions

HSP Interferometric Imaging

Salt Model

HSP Shot Gather

0 km

0 km

1.2 km

1.2 s

0 km

5 km

Mig. Image+Corr. Vel.

0 km

0 km

0 km

5 km

1.2 km

1.2 km

0 km

1.2 km

0 km

1.2 km

HSP Interferometric Imaging

Salt Model

HSP Shot Gather

0 km

0 km

1.2 km

1.2 s

0 km

5 km

Mig. Image+Corr. Vel.

0 km

0 km

0 km

HSP Interferometric Imaging

5 km

1.2 km

1.2 km

0 km

1.2 km

0 km

1.2 km

HSP Interferometric Imaging

Salt Model

HSP Shot Gather

0 km

0 km

1.2 km

1.2 s

0 km

5 km

Mig. Image+Corr. Vel.

HSP Image

0 km

0 km

0 km

5 km

1.2 km

1.2 km

0 km

1.2 km

0 km

1.2 km

HSP Interferometric Imaging

Salt Model

HSP Shot Gather

0 km

0 km

1.2 km

1.2 s

0 km

5 km

Mig. Image+Corr. Vel.

HSP Image

SWI-HSP Image

0 km

0 km

0 km

Garbage

5 km

1.2 km

1.2 km

0 km

1.2 km

0 km

1.2 km

HSP Interferometric Imaging

Salt Model

HSP Shot Gather

0 km

0 km

1.2 km

1.2 s

0 km

5 km

Mig. Image+Corr. Vel.

HSP Image

SWI-HSP Image

0 km

0 km

0 km

No Need for V

Garbage

5 km

1.2 km

1.2 km

0 km

1.2 km

0 km

1.2 km

Outline

Motivation

Interferometric Imaging

Synthetic VSP Data & Field Data

Conclusions

VSP Data

Image Below Salt Without

Knowing Salt Velocity

0 km2 km

0 km 3 km

Interferometric Image

X (m)

1000

1400

950

Depth (m)

1950

Well

256 Sources

V = 1.5 - 3.0 km/s

0

Depth (km)

SEG/EAGE Model

2

0

X (km)

3

X (km)

1.4

2.4

Xcross 60

X (km)

0

2.4

0

Time (s)

CRG 60

3

Xcorr Mig (45)

Xcorr. Mig(15’)

Kirchh Mig (45)

0.5

Depth (km)

2.0

0.5

2.5

0.5

2.5

0.5

2.5

X (km)

Outline

Motivation

Interferometric Imaging

Synthetic VSP Data & Field Data

Conclusions

Depth (ft)

30

900

0

Raw Data(CRG15)

Time (s)

0.3

Depth (ft)

30

900

0

Ghosts

Time (s)

0.3

X (ft)

X (ft)

0

400

0

400

200

Standard mig

Xcorr. mig

Depth (ft)

1300

Salt + Overburden

- Interferometric Tomography

- Interferometric Imaging: Kinematically equivalent to sources-receivers below datum

- True wave equation statics w/o V(x,y,z)

- HSP, VSP and CDP data

- Interferometric Tomography

- Interferometric Imaging: Kinematically equivalent to sources-receivers below datum

- True wave equation statics w/o V(x,y,z)

- HSP, VSP and CDP data

Salt + Overburden

Increased illumination coverage in the VSP image. VSP ->CDP

Eliminate the static errors in the well

No need to know source (RVSP) or receiver location (VSP)

Half sensitivity to velocity migration errors than mult. migration by “mirrors”.

Crosscorrelogram Migration Conclusions

Xcorr

Kirchhoff

Be careful about virtual multiple

Ghost is weaker than primary

Extra summation compared to KM

vs

Narrow Angle

Wide Angle

Conclusions

Loss of some lateral resolution?

Outline

Motivation

Crosscorrelation Migration

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Well

256 Sources

V = 1.5 - 3.0 km/s

0

Depth (km)

SEG/EAGE Model

2

0

X (km)

3

Acquisition Parameters:

Well location: (1.5 km, 0 km)

Source interval: 10 m

Source number: 256

Receiver interval: 10 m

Receiver depth range: 0.1 -1 km

Receiver number: 91

Sample interval: 1 ms

Recording length: 3 s

Well

0

1 km

Depth (km)

2

0

X (km)

3

Depth (km)

0.2

0.9

0

CSG 160

Time (s)

3

Depth (km)

0.2

0.9

0

Ghosts (CSG 160)

Time (s)

3

X (km)

1.4

2.4

Xcross 60

X (km)

0

2.4

0

Time (s)

CRG 60

3

Xcorr Mig (45)

Xcorr. Mig(15’)

Kirchh Mig (45)

0.5

Depth (km)

2.0

0.5

2.5

0.5

2.5

0.5

2.5

X (km)

0

Well Depth (m)

900

50

Raw Data

Static errors (ms)

-50

Static Errors at Well

Kirchhoff Migration

Static Error: 25 ms

Static Error: 50ms

2.5

X (km)

Static Error: 0

0.5

Depth (km)

2.0

0.5

2.5

0.5

2.5

0.5

Crosscorrelation Migration

Static Error: 25ms

Static Error: 50 ms

2.5

X (km)

Static Error: 0

0.5

Depth (km)

2.0

0.5

2.5

0.5

2.5

0.5

Velocity Model

Primary vs Multiple Image

0

Depth (km)

11

16

16

0

0

X (km)

X (km)

Contents

Motivation

Crosscorrelation Imaging Condition

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Depth (ft)

30

900

0

Raw Data(CRG15)

Time (s)

0.3

Depth (ft)

30

900

0

Ghosts

Time (s)

0.3

Field Data (CSG 25)

Trace No.

5

24

xcorr data (muted)

0.2

Time (s)

1.2

Master trace

Master trace

Trace No.

5

24

0.5

Raw data (muted)

Time (s)

1.4

X (ft)

X (ft)

0

400

0

400

200

Standard mig

Xcorr. mig

Depth (ft)

1300

Well data

Xcorr.

Exxon Data

Standard

0

Depth (ft)

1100

Outline

Motivation

Crosscorrelation Migration

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Increased illumination coverage in the VSP image. VSP ->CDP

Eliminate the static errors in the well

No need to know source (RVSP) or receiver location (VSP)

Half sensitivity to velocity migration errors than mult. migration by “mirrors”.

Crosscorrelogram Migration Conclusions

Xcorr

Kirchhoff

Be careful about virtual multiple

Ghost is weaker than primary

Extra summation compared to KM

vs

Narrow Angle

Wide Angle

Conclusions

Loss of some lateral resolution?

UTAM sponsors

Exxon for 2-D field data

J. Claerbout + J. Rickett

II evolved from daylight imaging

X (ft)

X (ft)

0

400

0

400

200

Standard mig

Xcorr. mig

Depth (ft)

1300

Geological Model

X(km)

0 4

0

Depth(km)

3

(2001)

Migration Result Using Crosscorrelation Imaging

X (km)

1.6

2.1

0

Too simple?

Widen illumination?

If there are static errors in well?

Time (s)

2.2

Widen the illumination coverage in the VSP image

Equivalent surface geometry

Xcorr

VSP geometry

Why Use Crosscorrelation Migration?

Seismic Ghost Reflection

Ghost

Direct

Find R(x,z) but not know source location

?

Master

Ghost

}

t

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

Direct

Direct has kinematics of primary reflection

Direct

gx

gx

Mx

g

x

x

x

M

M

Seismic Interferogram: Correlate Traces

Seismic Ghost Reflection

Ghost

Direct

1

2

M

Ghost

Direct Wave

Primary

Well

Receiver

Source

RVSP

Ghost Reflection Imaging Condition:

g

s

x

After Crosscorrelation of Two Traces at Locations g & g’

g

s

x

After Crosscorrelation of Two Traces at Locations g & g’

g

s

x

After Crosscorrelation of Two Traces at Locations g & g’

g

s

x

Recall Green’s Theorem

Every Surface Point = Source Point

Why is there insensitivity to static errors in the well?

g’

g

s

Static errors

x

Crosscorrelation Imaging Condition

Migrated Image

Crosscorrelograms

Crosscorrelogram Migration

Field Data

Well data

Xcorr. Migration

0

Depth (ft)

1100

Exxon Data

Well data

Standard Migration

0

Depth (ft)

1100

Wider, taller coverage. Eliminates well statics and uninteresting parts of the medium.

{

Above Source

Imaging

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

Wider Coverage

gx

gx

Mx

M

g

M

VSP

Kirchhoff Migrate psuedo-shot gathers

m(x) = (g, t + t )

gx

gx

Mx

M

g

M

Shifting Traces Removes Kinematic Effects

Of Propagating through Uninteresting Parts of Medium.

.

Source Moved to Depth

g

M

Can replace time-shifted traces by crosscorrelograms

0

10

Distance (km)

CDP Interferometric Imaging

Datuming with Reflections

KM image with Incorrect velocity

s

g

Model

km/s

0

3.2

m

3.0

Depth (km)

2.8

10

0

10

0

10

Distance (km)

Distance (km)

0

10

Distance (km)

CDP Interferometric Imaging

Datuming with Reflections

KM image with Incorrect velocity

s

g

Model

km/s

0

3.2

m

3.0

Depth (km)

2.8

10

0

10

0

10

Distance (km)

Distance (km)

0

10

Distance (km)

CDP Interferometric Imaging

Datuming with Reflections

KM image with Incorrect velocity

s

g

Model

km/s

0

3.2

m

3.0

Depth (km)

2.8

10

0

10

0

10

Distance (km)

Distance (km)