primary-only imaging condition yue wang. outline objective objective poic methodology poic...
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Primary-Only Imaging Primary-Only Imaging ConditionCondition
Yue WangYue Wang
OutlineOutline• • ObjectiveObjective
• POIC MethodologyPOIC Methodology
• • Synthetic Data TestsSynthetic Data Tests 5-layer model5-layer model
salt dome model salt dome model
• Unocal Field Data TestsUnocal Field Data Tests
• • Discussion and Future WorkDiscussion and Future Work
Synthetic Shot GatherSynthetic Shot Gather
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
4400 30003000
Multiples
Primary
2D Kirchhoff migration2D Kirchhoff migration
*^SourceSource
ReceiverReceiver
obsobs
obsobs = = SASA + + RARA
SASA RARA
Kirchhoff Migration ImageKirchhoff Migration Image
Artificial Multiple Image
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
6600 55
ProblemProblem
Standard imaging conditionStandard imaging condition
DataData( primary + multiple )( primary + multiple )
ImageImage( primary + multiple )( primary + multiple )
ObjectiveObjective
Primary-Only imaging conditionPrimary-Only imaging condition
DataData( primary + multiple )( primary + multiple )
ImageImage( primary + multiple )( primary + multiple )
OutlineOutline• • ObjectiveObjective
• POIC MethodologyPOIC Methodology
• • Synthetic Data TestsSynthetic Data Tests 5-layer model5-layer model
salt dome model salt dome model
• Unocal Field Data TestsUnocal Field Data Tests
• • Discussion and Future WorkDiscussion and Future Work
MethodologyMethodology
DataData PrimaryPrimary MultipleMultiple
== ++First-order MultipleFirst-order Multiple
Second-order MultipleSecond-order Multiple
Third-order MultipleThird-order Multiple
MethodologyMethodology
Primary ---------------- MultiplePrimary ---------------- Multiple
?? What DifferencesWhat Differences
Primary ReflectionsPrimary Reflections
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
AA
Multiple ReflectionsMultiple Reflections
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
AA
CC
BB
MethodologyMethodology
For a specific event:For a specific event:
Observed traveltime Observed traveltime obsobs
shooting angle shooting angle
incident angle incident angle
Shoot ray from sourceShoot ray from source
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
Shoot ray from receiverShoot ray from receiver
Find crossing pointFind crossing point
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
Cross point ACross point A
SASA RARA
Primary-Only Imaging Primary-Only Imaging Condition (POIC)Condition (POIC)
One event is primary reflectionOne event is primary reflectiononly if :only if :
obsobs = = SASA + + RARA
Multiple ReflectionsMultiple Reflections
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
AA
SASA RARA
Multiple ReflectionsMultiple Reflections
obsobs == SASA + + RARA
MethodologyMethodology DataData
( primary + multiple )( primary + multiple )
Standard Imaging Standard Imaging ConditionCondition
obsobs
ImageImage( primary + multiple )( primary + multiple )
Primary Only Imaging Primary Only Imaging ConditionCondition
obsobs , , and and
ImageImage( primary + multiple )( primary + multiple )
OutlineOutline• • ObjectiveObjective
• POIC MethodologyPOIC Methodology
• • Synthetic Data TestsSynthetic Data Tests 5-layer model5-layer model
salt dome model salt dome model
• Unocal Field Data TestsUnocal Field Data Tests
• • Discussion and Future WorkDiscussion and Future Work
5-Layer Model5-Layer Model
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
6600 55
*Source
GeophoneLine
Shot GatherShot Gather
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
4400 30003000
P1
P2
P3
P4
Kirchhoff Migration ImageKirchhoff Migration Image
123
4
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
6600 55
Kirchhoff Migration ImageKirchhoff Migration Image
Artificial Multiple Image
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
6600 55
Migration Image with POICMigration Image with POIC
123
4
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
6600 55
OutlineOutline• • ObjectiveObjective
• POIC MethodologyPOIC Methodology
• • Synthetic Data TestsSynthetic Data Tests 5-layer model5-layer model
salt dome model salt dome model
• Unocal Field Data TestsUnocal Field Data Tests
• • Discussion and Future WorkDiscussion and Future Work
Salt ModelSalt Model
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
3.53.500 55
*Source
GeophoneLine
Shot GatherShot Gather
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
4400 30003000
Kirchhoff Migration ImageKirchhoff Migration Image
1
2
345
6
6
A.M.I.A.M.I.
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
3.53.500 55
A.M.I.
Migration Image with POICMigration Image with POIC
1
2
345
6
6
Distance (km)Distance (km)
Dep
th (
km
)D
epth
(k
m)
00
3.53.500 55
OutlineOutline• • ObjectiveObjective
• POIC MethodologyPOIC Methodology
• • Synthetic Data TestsSynthetic Data Tests 5-layer model5-layer model
salt dome model salt dome model
• Unocal Field Data TestsUnocal Field Data Tests
• • Discussion and Future WorkDiscussion and Future Work
Processed CSGProcessed CSG
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
44175175 31753175
M1M2
NMO Corrected CMGNMO Corrected CMG
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
66175175 31753175
M2
CMG after Dip FilteringCMG after Dip Filtering
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
66175175 31753175
M2
Seismogram in Seismogram in -p Domain-p Domain
pp
Tim
e (s
)T
ime
(s)
00
66-200-200 400400
Multiple
Primary
Muting in Muting in -p Domain-p Domain
pp
Tim
e (s
)T
ime
(s)
00
66-200-200 400400
CMG after Muting in CMG after Muting in -p -p
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
66175175 31753175
M2
Stack before MutingStack before MutingT
ime
(s)
Tim
e (s
)00
44
M1
CDP NumberCDP Number313313 14001400
M2
M2
Stack after MutingStack after MutingT
ime
(s)
Tim
e (s
)00
M2
M2
CDP NumberCDP Number44
313313 14001400
Kirchhoff ImageKirchhoff ImageD
epth
(m
)D
epth
(m
)00
40004000
M1M2
M2
Distance (m)Distance (m)20002000 90009000
POIC ImagePOIC ImageD
epth
(ft
)D
epth
(ft
)00
40004000
M1M2
M2
Distance (m)Distance (m)20002000 90009000
ConclusionsConclusions
• POIC Works for synthetic dataPOIC Works for synthetic data
• Encouraging results for field dataEncouraging results for field data
• POIC need more accurate velocity modelPOIC need more accurate velocity model
Future WorkFuture Work
• • Apply to other field dataApply to other field data
• • Improve velocity model estimateImprove velocity model estimate
AcknowledgementAcknowledgement
We are grateful to the 1999 sponsors We are grateful to the 1999 sponsors of the UTAM consortium for the of the UTAM consortium for the financial supportfinancial support
Migration with POICMigration with POIC
Four Steps:Four Steps:
(1) pick seismic events automatically;(1) pick seismic events automatically;
obsobs
Migration with POICMigration with POIC
Four Steps:Four Steps:
(2) calculate incidence and shooting angles (2) calculate incidence and shooting angles andand for one event using local slant for one event using local slant stack;stack;
Migration with POICMigration with POIC
Four Steps:Four Steps:
(3) ray tracing and find the crossing point;(3) ray tracing and find the crossing point;
SASA + + RARA
Find crossing pointFind crossing point
OffsetOffset
Dep
thD
epth
*
^
SourceSource ReceiverReceiver
Cross point ACross point A
SASA RARA
(4) (4) obs obs = = SASA + + RARA ??
No: Discard this event;No: Discard this event; Yes: Migrate this event;Yes: Migrate this event;
Migration with POICMigration with POIC
Raw CSGRaw CSG
Distance (m)Distance (m)
Tim
e (s
)T
ime
(s)
00
44175175 31753175
CMGCMG
Offset (m)Offset (m)
Tim
e (s
)T
ime
(s)
00
66175175 31753175
M1M2