Autocorrelogram Migration Autocorrelogram Migration of Drill-Bit Data of Drill-Bit Data

Jianhua Yu, Lew Katz, Jianhua Yu, Lew Katz,

Fred Followill, and Gerard T. SchusterFred Followill, and Gerard T. Schuster

OutlineOutline Motivation and ObjectiveMotivation and Objective

Autocorrelogram MigrationAutocorrelogram Migration

ExamplesExamples

Synthetic DataSynthetic Data UPRC data UPRC data

SummarySummary

IVSPWD ObjectiveIVSPWD Objective Provide Look-ahead Image Below Drill Bit Provide Look-ahead Image Below Drill Bit

Reduce Uncertainty in DrillingReduce Uncertainty in Drilling

?

ProblemsProblems

No Source WaveletNo Source Wavelet

No Source Initiation TimeNo Source Initiation Time

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

Deviated WellDeviated Well

Autocorrelogram Migration

No need

to know source

wavelet

No limits to deviated well

SolutionSolution

No need to know initial time

OutlineOutline

. Motivation and Objective. Motivation and Objective . Autocorrelogram Migration . Autocorrelogram Migration . Examples . Examples . Summary . Summary

WellWell

Drill bitDrill bit

ReceiverReceiver

Primary

Primary, Ghost and Direct WavesPrimary, Ghost and Direct Waves

Direct Wave

Ghost

Primary Autocorrelogram Primary Autocorrelogram

Imaging Condition:Imaging Condition:

x

g

ssg

xg

sx

xgsx

sg AutocorrelateAutocorrelate

TraceTraceDD

RR

Primary Autocorrelogram Primary Autocorrelogram

Imaging Condition:Imaging Condition:

x

ssg

xg

sx

xgsx sg

gD*DD*D

D*RD*R

}}

Primary Autocorrelogram Primary Autocorrelogram

Imaging Condition:Imaging Condition:

x

g

s

sg

sg

xg

sx

xgsxp BONUS:

Mitigatessrc/rec statics!

x

g

s xg

xx0

sg0

xx

Ghost Autocorrelogram Imaging Ghost Autocorrelogram Imaging ConditionCondition:

xgxxsx

00

sg

0x

GhostGhost

AutocorrelateAutocorrelate TraceTraceDD

GG

x

g

s xg

xx0

sg0

xx

xgxxsx

00sg

0x

Ghost Autocorrelogram Imaging Ghost Autocorrelogram Imaging ConditionCondition:

D*DD*D

D*GD*G

}}

x

g

s xg

xx0

sg0

xx

xgxxsxg

00

0x

sg

Ghost Autocorrelogram Imaging Ghost Autocorrelogram Imaging ConditionCondition:

Autocorrelogram MigrationAutocorrelogram Migration

),,()(,

..

sg

gsrrm

åx

Migrated Migrated ImageImage

Autocorrelation Autocorrelation Function Function

Imaging Cond.Imaging Cond.

Auto.Auto. Migration ProcedureMigration Procedure

dd

Filter dataFilter data

Pre-process raw dataPre-process raw data

Autocorrelate seismic traces:Autocorrelate seismic traces: ),(sgrrd

Autocorrelogram migration with Autocorrelogram migration with primary & ghost imaging conditionsprimary & ghost imaging conditions

OutlineOutline

. Motivation and Objective. Motivation and Objective . Autocorrelogram Migration . Autocorrelogram Migration . Examples . Examples . Summary . Summary

Geological ModelGeological Model

0

Dep

th (

m)

3

40X (m)

V1

V2

V4

V3

V5

V6

Velocity ModelVelocity Model0 4

0

3

Dep

th(k

m)

X(km) 0 40

3

X(km)

3.5

2.0

3.5

2.0

Interval Velocity RMS Velocity

Shot GatherShot Gather

1 2000

4

Tim

e (s

)

CSG 10

1 2000

4

Tim

e (s

)

TracesTraces

AutocorrelogramAutocorrelogram

Primary Autocorrelogram Primary Autocorrelogram Depth MigrationDepth Migration

Dep

th (

km

)

2.82.8

001.61.6 2.12.1

X (km)X (km)

With primary+ghost

X (km)X (km)

2.82.8

001.61.6 2.12.1

Without ghost

X (km)X (km)

2.82.8

001.61.6 2.12.1

Without ghost

Ghost Autocorrelogram Ghost Autocorrelogram Depth MigrationDepth Migration

Dep

th (

km

)

2.82.8

001.61.6 2.12.1

X (km)X (km)

With primary+ghost

Acquisition SurveyAcquisition Survey

00

00 4.54.5

-5-5

East (kft)East (kft)

North

(kft)

North

(kft)

Well Rig 3C Receivers

Drill bit

10

Dep

th (

kft

)D

epth

(k

ft)

0

Main Acquisition ParametersMain Acquisition Parameters

Drill-bit Depth: 9188 ftDrill-bit Depth: 9188 ft

Offset Range: 1135-4740 ftOffset Range: 1135-4740 ft

Recording Length: 20 sRecording Length: 20 s

Sample Interval: 2 msSample Interval: 2 ms

Station Number: 10Station Number: 10

Main Processing StepsMain Processing Steps Trace editing and static shiftTrace editing and static shift

Frequency panel analysis and noise eliminationFrequency panel analysis and noise elimination

Velocity analysisVelocity analysis

Amplitude balance and energy normalizationAmplitude balance and energy normalization

Calculating cross- and autocorrelograms, vertical stackingCalculating cross- and autocorrelograms, vertical stacking

Cross- and Autocorelogram migrationAutocorelogram migration

1 Trace # 100

7

Tim

e (s

)

5-40 Hz5-40 Hz

1 Trace # 10

Raw CGR 96Raw CGR 96 Proc. CGR 96Proc. CGR 96

Autocorrelogram of CSG 96 Autocorrelogram of CSG 96

1 100

4

Tim

e (s

)

1 10 1 10

8 s 12 s 16 s

0 1

3.2

Tim

eT

ime

(s)

(s)

500 0 500

Autocorrlogram Migration ImagesAutocorrlogram Migration Images

X(ft)X(ft) X(ft)X(ft)

No reflections

1

3.2

Primary ImagePrimary Image Ghost ImageGhost Image

Correlation Window = 8 sCorrelation Window = 8 s

Acquisition Survey MapAcquisition Survey Map

Well Rig

3C Receivers

Drill bit

00

00 15001500 30003000 45004500-5000-5000

East (ft)East (ft)

Nor

th (

ft)

Nor

th (

ft)

Line ACC4

1.0

3.0

2.0

1265 1235 1215

Tim

e (s

)

SP

Drill Drill holehole

Primary Autocorrelogram Image (Primary Autocorrelogram Image (Corr. window=8 sCorr. window=8 s))

3.0

2.0

1.0T

ime

(s)

SP 1255 1235 1215

Ghost Autocorrelogram Image(Ghost Autocorrelogram Image(Corr. window=8 s)Corr. window=8 s)

DrillDrill holehole

SUMMARYSUMMARY

Works for deviated wellsWorks for deviated wells

Auto migration images show rough Auto migration images show rough correlation to surface-CDP sectioncorrelation to surface-CDP section

Autocorrelation Migration:Autocorrelation Migration:

Mitigates src/rec staticMitigates src/rec staticCompresses waveletCompresses wavelet

No need to know wavelet or start timeNo need to know wavelet or start time

Beware of virtual multiples!Beware of virtual multiples!

AcknowledgementsAcknowledgements

• We appreciate DOE’s Financial support We appreciate DOE’s Financial support

• We are grateful to Union Pacific We are grateful to Union Pacific Resources Corp. for donating this dataResources Corp. for donating this data

• I thank the sponsors of the UTAM I thank the sponsors of the UTAM consortium for their financial supportconsortium for their financial support

SUMMARYSUMMARY

Difficulty of separating upgoing Difficulty of separating upgoing and downgoing wave can cause and downgoing wave can cause artifacts in migration imageartifacts in migration image

What is NextWhat is Next

Improve the method for real-Improve the method for real-time purposetime purpose

Reduced the virtual multiple and Reduced the virtual multiple and other wave influenceother wave influence

Developing 3D autocorrelogram Developing 3D autocorrelogram methodmethod

1.6 2.1X (km)

Without ghost

1.6 2.10

2.2

Tim

e (s

)

X (km)

With primary+ghost

Primary Autocorrelogram Primary Autocorrelogram Time MigrationTime Migration

1.6 2.1X (km)

Without primary

1.6 2.10

2.2

Tim

e (s

)

X (km)

With ghost+primary

Ghost Autocorrelogram Ghost Autocorrelogram Time MigrationTime Migration

OutlineOutline

. Objective. Objective . . Autocorrelogram Migration . Examples . Examples . Summary . Summary

Processed CSG 96 Part of CRG 6Processed CSG 96 Part of CRG 6

1 100

7

Tim

e (s

)

1 130.5

4.5

Tim

e (s

)

5-40 Hz5-40 Hz

Drill-bit Data of CSG #96Drill-bit Data of CSG #961 10

0

7

Tim

e (s

)Trace Number

Frequency Panel AnalysisFrequency Panel Analysis1 10

0

7

Tim

e (s

)

1 100

7

Tim

e (s

)

< 5 Hz 5-15 Hz

Frequency Panel AnalysisFrequency Panel Analysis1 10

0

7

Tim

e (s

)

1 100

7

Tim

e (s

)

15-25 Hz 25-40 Hz