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