midyear overview of year 2001 utam results t. crosby, y. liu, g. schuster, d. sheley, j. sheng, h....

2001 Sponsors2001 Sponsors• AramcoAramco• Amerada HessAmerada Hess• BP-AMOCOBP-AMOCO• ChevronChevron• ConocoConoco• Japan Nat. Oil Japan Nat. Oil

Co.Co.

• Inst. Mex. Pet.Inst. Mex. Pet.• INCOINCO• MarathonMarathon• PhillipsPhillips• SisimageSisimage• TexacoTexaco• VeritasVeritas

Salient 2001 Research Salient 2001 Research AchievementsAchievements

1. Wave-Beam Migration1. Wave-Beam Migration

ExpenseExpense

Acc

ura

cyA

ccu

rac y

Full-WaveFull-Wave

Ray-BeamRay-BeamKirchhoffKirchhoff

Phase-ShiftPhase-Shift

Migration Accuracy vs $$$Migration Accuracy vs $$$

Wave-Wave-BeamBeam

No Approx.No Approx.MultiplesMultiplesAnti-aliasingAnti-aliasing

SS RR

ImageImagePointPoint

Fresnel ZoneFresnel Zone

Smear Reflection along WavepathSmear Reflection along Wavepath

Slant StackSlant Stack

Smear Reflection along WavepathSmear Reflection along Wavepath

Standard FDStandard FDWavefront FDWavefront FD

0 4.5 km0 4.5 km

00

1.5 km1.5 km

Cost Ratio of Standard /WavefrontCost Ratio of Standard /Wavefront

# Gridpts along side# Gridpts along side500 3000500 3000

4545

55Cos

t R

atio

Cos

t R

atio

Prestack Migration ImagePrestack Migration Image

ModelModel

00

1.5 km1.5 km

0 4.5 km0 4.5 km

00

1.5 km1.5 km

1.5 km/s1.5 km/s2.2 km/s2.2 km/s

1.8 km/s1.8 km/s

Dep

th (

kft

)D

epth

(k

ft)

00

33Distance (kft)Distance (kft)00 55

Eikonal Traveltime FieldEikonal Traveltime Field

Dep

th (

kft

)D

epth

(k

ft)

00

33Distance (kft)Distance (kft)00 55

Wave-Equation Traveltime FieldWave-Equation Traveltime Field

Dep

th (

km

)D

epth

(k

m)

00

33Distance (km)Distance (km)00 55

KirchhoffKirchhoff Wave Equation TraveltimesWave Equation Traveltimes

ModelModelD

epth

(k

ft)

Dep

th (

kft

)

55

1111

Distance (km)Distance (km)00 55 Distance (km)Distance (km)00 55

Wavefront Reverse Time MigrationWavefront Reverse Time Migration

Open QuestionsOpen Questions1. More Storage1. More Storage2. Resorting Overhead 2. Resorting Overhead 3. Large scale tests?3. Large scale tests?

1. Order Mag. Cheaper than 3-D RT1. Order Mag. Cheaper than 3-D RT2. Fewer Artifacts2. Fewer Artifacts3. Optimal Accuracy3. Optimal Accuracy



2. Multiple Removal POIC2. Multiple Removal POIC

Multiple Removal by Multiple Removal by Primary-Only Imaging ConditionPrimary-Only Imaging Condition

Hongchuan SunHongchuan Sun

Forward ModelingForward Modeling

DistanceDistance

Dep

thD

epth

SS RRPrimary Multiple

SS RR

DistanceDistance

Dep

thD

epth

SS RR

RRSS

Migration with POICMigration with POIC

DistanceDistance

Dep

thD

epth

SS RR

SS RR

P

The raysThe rays intersectintersectat point P, at point P, and the and the traveltime traveltime

SP SP ++RP RP ==obs obs

Multiple RemovalMultiple Removal

The raysThe rays never never intersect;intersect; or the or the traveltime traveltime

SP SP ++RP RP == obs obs

DistanceDistance

Dep

thD

epth

SS RR

RRSS

P

Distance (kft)Distance (kft)

Dep

th (

kft

)D

epth

(k

ft)

00

1111

00 5151

Dep

th (

kft

)D

epth

(k

ft)

00

1111

Dep

th (

kft

)D

epth

(k

ft)

00

1111

Model

KM Image

POIC Image

SEG/EAGE 2-D Salt DataSEG/EAGE 2-D Salt Data

Dep

th (

kft

)D

epth

(k

ft)

55

1111

Distance (kft)Distance (kft)1515 5151

KM Image POIC Image

ModelD

epth

(k

ft)

Dep

th (

kft

)

55

1111

Distance (kft)Distance (kft)1515 5151 Distance (kft)Distance (kft)1515 5151

Offsets Used: 0 ~ 14000 ft


Dep

th (

kft

)D

epth

(k

ft)

00

1111

00 1717 Distance (kft)Distance (kft)00 1717 Distance (kft)Distance (kft)00 1717

KM Image Model POIC Image


ConclusionsConclusions

• POIC effectively remove surfacePOIC effectively remove surface related multiplesrelated multiples• POIC performs much better whenPOIC performs much better when near-offset data are not usednear-offset data are not used• POIC should be applicable toPOIC should be applicable to interbed multiple removalinterbed multiple removal




3. Sparse Fequency Migration3. Sparse Fequency Migration

Fourier Finite Difference Fourier Finite Difference Migration with Sparse Migration with Sparse

FrequenciesFrequencies

Jianhua YuJianhua Yu

Department of Geology & GeophysicsDepartment of Geology & Geophysics

University of UtahUniversity of Utah

ObjectiveObjective

Improve computational efficiency Improve computational efficiency

of wave-equation extrapolation of wave-equation extrapolation

Hi-quality Image Hi-quality Image

Frequency Domain Migration Frequency Domain Migration

70 Fourier Finite Difference Method70 Fourier Finite Difference Method

1/4 Sparser Frequency Domain Sampling1/4 Sparser Frequency Domain Sampling

oo

Comparison of 3D Impulse Response Comparison of 3D Impulse Response

X (km)X (km)00 44

Dep

th (

km

)D

epth

(k

m)

00

2.42.4

FD algorithmFD algorithm

Main energy Main energy wider angle FFDwider angle FFD

Dep

th (

km

)D

epth

(k

m)

00

2.42.4

2D Impulse Response 2D Impulse Response

X (km)X (km)00 44

Dep

th (

km

)D

epth

(k

m)

00

2.42.4

Standard wider angle Standard wider angle FFDFFD

X (km)X (km)00 44

Main energy wider angle Main energy wider angle FFDFFD

(Velocity contrast, i.e., V/Vmin = 3.0)(Velocity contrast, i.e., V/Vmin = 3.0)

Comparison of FFD and Main Energy FFD Comparison of FFD and Main Energy FFD Migration Migration X (km)X (km)

00 44D

epth

(k

m)

Dep

th (

km

)

00

2.42.4

FFD algorithmFFD algorithm

Main energy Main energy FFD FFD (computational (computational time saving time saving about 38 %)about 38 %)

Dep

th (

km

)D

epth

(k

m)

00

2.42.4

3D SEG/EAGE Zero Offset Imaging Result 3D SEG/EAGE Zero Offset Imaging Result

X (km)X (km)00 44

Dep

th (

km

)D

epth

(k

m) 00

2.02.0

Dep

th (

km

)D

epth

(k

m) 00

2.02.0

Y (km)Y (km)00 88

440000

88

X (km)X (km)

Y (k

m)

Y (k

m)

Strengths:Strengths:

Efficient forward extrapolationEfficient forward extrapolation

Wider angle FFD operatorWider angle FFD operator

Less numerical anisotropy in 3D by Less numerical anisotropy in 3D by applying high order implicit FD algorithmapplying high order implicit FD algorithm

Weaknesses:Weaknesses:Coding ComplexityCoding Complexity

Fewer Frequencies Reduced QualityFewer Frequencies Reduced Quality





4. AVO Migration Decon4. AVO Migration Decon

Prestack Migration Decon Prestack Migration Decon for AVO Analysisfor AVO Analysis




Solution: Deconvolve the point Solution: Deconvolve the point scatterer response from the migrated scatterer response from the migrated imageimage

TTrr = ( = ( L LL L ) m ) m

-1-1

Reflectivity MigratedReflectivity Migrated SectionSection

ReasonReason:: m = m = L L ddTT

MigratedMigratedSectionSection

DataData

butbut dd = L = L rrLL rr

Migration SectionMigration Section = = Blured Blured Image ofImage of r r

Objective of PMD AVOObjective of PMD AVO

Suppress unwanted interference Suppress unwanted interference

Increase estimation accuracy of AVO Increase estimation accuracy of AVO

parametersparameters

Enhance resolution of AVO sections Enhance resolution of AVO sections

Zoom View of AVO parameter Section Zoom View of AVO parameter Section Before and After PMD Before and After PMD

X(km)X(km)1.01.0 2.02.0

Tim

e (s

)T

ime

(s)

0.50.5

2.02.0

Before PMDBefore PMD

Tim

e (s

)T

ime

(s)

After PMDAfter PMD

0.50.5

2.02.0

X(km)X(km)1.01.0 2.02.0

Migration CRG Before and After PMD Migration CRG Before and After PMD

TraceTrace TraceTrace

11 6060 11 6060

Tim

e (s

)T

ime

(s)

0.60.6

1.81.8

Tim

e (s

)T

ime

(s)

Before PMDBefore PMD After PMDAfter PMD

0.60.6

1.81.8

Comparison of Amplitude & Angle Comparison of Amplitude & Angle Estimation Before and After PMD Estimation Before and After PMD

2rd layer2rd layer

Am

plit

ud

eA

mp

litu

de

11

00

1st layer1st layer 3rd layer3rd layer

+: Before PMD *: After PMD

Solid line: Theoretical value

Angle Angle Angle0 60 0 60 0 60

Summary & FutureSummary & Future

• MD reduces artifactsMD reduces artifacts

• MD improves resolution & AVOMD improves resolution & AVO

• MD field data case by Feb.MD field data case by Feb.






5. Joint Autocorrelation Imaging5. Joint Autocorrelation Imaging

Joint Imaging Using Both Primary Joint Imaging Using Both Primary

and Multiple for IVSP Dataand Multiple for IVSP Data




Problems for Deviated and Problems for Deviated and Horizontal wellHorizontal well

No Source Wavelet & Initiation TimeNo Source Wavelet & Initiation Time

Not Easy to Get Pilot Signal in Not Easy to Get Pilot Signal in

Hard to Separate Primary and GhostHard to Separate Primary and Ghost

Static Shift at Source and ReceiverStatic Shift at Source and Receiver

Auto. Imaging using Primary and Ghost

Geological ModelGeological Model

0

Dep

th (

m)

3

40X (m)

V1

V2

V4

V3

V5

V6

Shot Gather and AutocorrelogramShot Gather and Autocorrelogram

1 2000

4

Tim

e (s

)

1 2000

4

Tim

e (s

)

TracesTraces

1.6 2.10

2.2

Tim

e (s

)

X (km)

Standard Migration

1.6 2.1X (km)

Joint Migration

Eliminate Interferences using Joint Eliminate Interferences using Joint Imaging in Time DomainImaging in Time Domain

Eliminate Interferences using Joint Eliminate Interferences using Joint Imaging in Depth DomainImaging in Depth Domain

Dep

th (

km

)

2.82.8

001.61.6 2.12.1

X (km)X (km)

Conventional Imaging

X (km)X (km)

1.61.6 2.12.1

Joint Imaging

Kirchhoff and Auto. Migration with Kirchhoff and Auto. Migration with Statics Error at Source and Receiver Statics Error at Source and Receiver

Dep

th (

km

)

2.82.8

001.61.6 2.02.0

X (km)X (km)

Kirchhoff joint migrationg

1.61.6 2.02.0

X (km)X (km)

Auto. joint migrationg

SUMMARYSUMMARY

Works for deviated and horizontal wellWorks for deviated and horizontal well

Eliminating static shift errorsEliminating static shift errors

Avoiding separating primary and ghost Avoiding separating primary and ghost waves for horizontal well datawaves for horizontal well data

Joint Migration method:

Don’t require pilot signal & wavelet Don’t require pilot signal & wavelet initial timeinitial time






5. Joint Autocorrelation Imaging5. Joint Autocorrelation Imaging

6. Xwell Statics & Tomography6. Xwell Statics & Tomography

INCO Project ReportINCO Project Report

M. ZhouM. Zhou

Geology and Geophysics Department Geology and Geophysics Department University of UtahUniversity of Utah

ObjectiveObjective

Invert velocity & geometry jointlyInvert velocity & geometry jointly

Normalized Traveltime Residuals vs. Normalized Traveltime Residuals vs. Velocity & Geometry ChangesVelocity & Geometry Changes

500 m500 m

V=5.0km/secV=5.0km/sec

Vel

ocity

(km

/sec

)V

eloc

ity (

km/s

ec)

Horizontal shift (m)Horizontal shift (m) Vertical Shift (m)Vertical Shift (m) Rotation (degree)Rotation (degree)

2.52.5

7.57.5

5.05.0

0.00.0

1.01.0

0.50.5

0.00.0 250250-250-2500.00.0 250250-250-250 0.00.0 3030-30-30

ProblemsProblems

1) Geometry is coupled with 1) Geometry is coupled with velocityvelocity

2) Joint inversion is ill-posed 2) Joint inversion is ill-posed

a) Synthetic Modela) Synthetic Model b) Standard Inversion with 10 m shot shiftb) Standard Inversion with 10 m shot shift

c) Joint Inversion for the shot shiftc) Joint Inversion for the shot shift( all shots have the same shift )( all shots have the same shift )

d) Joint Inversion + a priori information d) Joint Inversion + a priori information for individual shot locationsfor individual shot locations

De

pth

(m

)D

ep

th (

m)

200200

00

100100

00 8080

00 8080-10-10

De

pth

(m

)D

ep

th (

m)

200200

00

100100

00 8080-10-10Offset (m)Offset (m) Offset (m)Offset (m)

8080-10-10 1010

Km/sKm/s

2.52.5

5.05.0

4.54.5

3.03.0

Km/sKm/s

2.52.5

5.05.0

4.54.5

3.03.0

Geometry Error: synthetic example IGeometry Error: synthetic example I

a) Synthetic Modela) Synthetic Model

c) Standard Inversion with +10 m shot shiftsc) Standard Inversion with +10 m shot shifts

De

pth

(m

)D

ep

th (

m)

300300

00

100100

00 8080-10-10

De

pth

(m

)D

ep

th (

m)

200200

00

100100


8080-10-10 1010

Geometry Error: synthetic example IIGeometry Error: synthetic example II

200200

00 100100-10-10

300300

Km/sKm/s

2.02.0

3.23.2

2.82.8

2.42.4

Km/sKm/s

2.02.0

3.23.2

2.82.8

2.42.4

b) Standard Inversion without shot shiftb) Standard Inversion without shot shift

d) Joint Inversion for the shot shiftd) Joint Inversion for the shot shift

a) Synthetic Modela) Synthetic Model

c) Joint Inversion + a priori information c) Joint Inversion + a priori information for the shot shiftfor the shot shift

d) Joint Inversion + a priori information d) Joint Inversion + a priori information for individual shot locationsfor individual shot locations

De

pth

(m

)D

ep

th (

m)

300300

00

100100

00 8080-10-10

De

pth

(m

)D

ep

th (

m)

200200

00

100100


8080-10-10 1010

Geometry Error: synthetic example IIGeometry Error: synthetic example II

200200

00 100100-10-10

300300

Km/sKm/s

2.02.0

3.23.2

2.82.8

2.42.4

Km/sKm/s

2.02.0

3.23.2

2.82.8

2.42.4

b) Standard Inversion without shot shiftb) Standard Inversion without shot shift

ConclusionsConclusions

• works for simple modelworks for simple model

• needs additional informationneeds additional information

Joint inversionJoint inversion

midyear overview of year 2001 utam results t. crosby, y. liu, g. schuster, d. sheley, j. sheng, h....

Documents

multiple removal poic3

research achievements1

wavebeam migration2

d segeage

ftconclusions poic

image poic imagesegeage

comparison of ffd

resolution of avo section