wavepath migration versus kirchhoff migration: 3-d prestack examples

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H. Sun and G. T. Schuster. University of Utah. Wavepath Migration versus Kirchhoff Migration: 3-D Prestack Examples. Outline. Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results Conclusions. Specular Ray. Forward Modeling. - PowerPoint PPT Presentation

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  • Wavepath Migration versus Kirchhoff Migration: 3-D Prestack Examples

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results Conclusions

  • Forward Modeling( Xg, 0 )( Xs, 0 )

  • 3D Kirchhoff Migration( Xg, 0 )( Xs, 0 )

  • 3-D KM of a Single TraceRSABC

  • Problems in Kirchhoff MigrationTraveltime InformationWhere Was Wave Reflected ?The Whole Fat Ellipsoid !Problem 1Strong Far-FieldMigration ArtifactProblem 2Slow for 3-D IterativeVelocity Analysis

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results Conclusions

  • 3D Wavepath Migration( Xg, 0 )

  • 3-D WM of a Single TraceRSABC

  • Traveltime + Ray DirectionWavepath Migration

  • To Achieve Higher CPU Efficiency Compared to 3-D KM To Generate Comparable or Better Image Quality than 3-D KMKey Goals of 3-D WM

  • Related References Time-Map Migration Sherrif & Geldhart (1985) Wave Equation Tomography Woodward & Rocca (1988) Gaussian Beam Migration Ross Hill (1990) Kirchhoff Beam Migration Yonghe Sun et al., (1999)

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results Conclusions

  • Key Steps in WMRSQuasi-ellipsoid

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results 3-D Prestack Point Scatterer Data 3-D Prestack SEG/EAGE Salt Data 3-D Prestack West Texas Field Data Conclusions

  • 3-D Prestack KM Point Scatterer Response ReflectivityY Offset (km)X Offset (km)1-0.501ReflectivityY Offset (km)X Offset (km)1-0.0100.02ReflectivityY Offset (km)X Offset (km)1-0.0500.1ReflectivityY Offset (km)X Offset (km)1-0.200.41111Z0Z0-1Z0-9Z0+8

  • ReflectivityY Offset (km)X Offset (km)1-0.501ReflectivityY Offset (km)X Offset (km)1-0.0100.02ReflectivityY Offset (km)X Offset (km)1-0.0500.1ReflectivityY Offset (km)X Offset (km)1-0.200.411113-D Prestack WM Point Scatterer Response Z0Z0-1Z0-9Z0+8

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results 3-D Prestack Point Scatterer Data 3-D Prestack SEG/EAGE Salt Data 3-D Prestack West Texas Field Data Conclusions

  • A Common Shot GatherTrace Number1390Time (sec)05.0

  • Inline Velocity ModelOffset (km)09.2Depth (km)03.8

  • Inline KM (CPU=1)Inline WM (CPU=1/33)Offset (km)09.203.8Depth (km)Offset (km)09.2

  • Inline KM (CPU=1)Inline WM (CPU=1/170)Offset (km)09.203.8Depth (km)Offset (km)09.2(subsample)

  • Zoom Views of Inline Sections Offset: 3~6.5 km, Depth: 0.3~1.8 kmWMModelKM SubWM

  • Offset: 1.8~4 km, Depth: 0.6~2.1 kmWMModelKM SubWMZoom Views of Crossline Sections

  • Inline: 1.8~7.2 km, Crossline: 0~4 kmWMModelKM SubWMHorizontal Slices (Depth=1.4 km)

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results 3-D Prestack Point Scatterer Data 3-D Prestack SEG/EAGE Salt Data 3-D Prestack West Texas Field Data Conclusions

  • A Common Shot GatherTrace Number54193Time (sec)03.4

  • Inline KM (CPU=1)Inline WM (CPU=1/14)Offset (km)0.44.50.83.8Depth (km)Offset (km)0.44.5

  • Inline KM (CPU=1)Inline WM (CPU=1/50)Offset (km)0.44.50.83.8Depth (km)Offset (km)0.44.5(subsample)

  • Crossline KM (CPU=1)Crossline WM (CPU=1/14)Offset (km)0.33.50.83.3Depth (km)Offset (km)0.33.5

  • Crossline KM (CPU=1)Crossline WM (CPU=1/50)(subsample)Offset (km)0.33.50.83.3Depth (km)Offset (km)0.33.5

  • Inline: 0~4.6 km, Crossline: 0~3.8KM (CPU=1)Horizontal Slices (Depth=2.5 km) WM (CPU=1/14)WM (Sub, CPU=1/50)

  • Outline Problems in Kirchhoff Migration Wavepath Migration Implementation of WM Numerical Results Conclusions

  • Conclusions SEG/EAGE Salt Data Fewer Migration Artifacts Better for Complex Salt Boundary Higher Computational Efficiency

    CPU KM: 1 WM: 1/33 Subsampled WM: 1/170

  • Conclusions West Texas Field Data Fewer Migration Artifacts Similar Image Quality Higher Computational Efficiency

    CPU KM: 1 WM: 1/14 Subsampled WM: 1/50

  • AcknowledgementsWe thank UTAM sponsorsfor their financial support