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Aerial View Eucalyi River, Peru

Seismic View: 2 km Deep Meandering River. Aerial View Eucalyi River, Peru. Overview of Seismic Imaging. Jerry Schuster KAUST. Outline. Forward Acoustic Problem. Inverse Acoustic Problem. Seismic Experiment. Seismic Migration. c r. c r. 2. 1. 2. 1. ZO Seismic Section.

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Aerial View Eucalyi River, Peru

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  1. Seismic View: 2 km Deep Meandering River Aerial View Eucalyi River, Peru

  2. Overview of Seismic Imaging Jerry Schuster KAUST

  3. Outline • Forward Acoustic Problem • Inverse Acoustic Problem • Seismic Experiment • Seismic Migration

  4. c r c r 2 1 2 1 ZO Seismic Section Depth Time

  5. Monterey Seismic Image 0 km 2 km 0 km 0.1 km Monterey Optical Image

  6. Acoustic Forward Problem Pressure Source r r ( r r ) o ( r ) k = w/c Given: r d(r) Find: dr Soln: c 1 2 2 d + k d = o r c ò = g d ( r ) 2 Depth

  7. r r r r ( ( r r r r ) ) o o ( ( r r ) ) c r c r 1 2 1 2 dr Depth Time r r ò = = g g d d ( ( r r ) ) Goal: Compute ZO Seismic Section

  8. Common Shot Gather Time Depth

  9. Common Midpoint Gather Midpoint Time Depth

  10. Normal Moveout Correction Midpoint Time Depth

  11. Stacked Trace Midpoint Time Depth

  12. Stacked Seismic Section Time Depth

  13. Outline • Forward Acoustic Problem • Inverse Acoustic Problem • Seismic Experiment • Seismic Migration

  14. What is the Problem? Incorrect location. You think events originated directlybelow geophones. Events Can Originate Updip V/2 D=VT/2 Depth Time

  15. What is another Problem? Events Originate Pt. Diffractors Depth Time

  16. corner 0 km 30 m 0 m 30 m

  17. ZO Data Migration (Relocates Reflections back to Place of Origin) ZO Data 0 km 3 km 0 km 7 km

  18. Seismic Inverse Problem 2 Soln: min || Lo-d || ‘ waveform inversion -1 T T migration o = [L L] L d T L d Given: d= Lo Find: o(x,y,z)

  19. Outline • Forward Acoustic Problem • Inverse Acoustic Problem • Seismic Experiment • Seismic Migration

  20. ZO Migration Smear Reflections along Fat Circles   rs + T rs o 2-way time r x s  2 2 (x-x ) + y = d(x , ) s rs .5c s

  21. ZO Migration Smear Reflections along Fat Circles  rs & Sum  2-way time x d(x , ) s

  22. ZO Migration Smear Reflections along Circles  rs & Sum  2-way time r d(x , ) s

  23. ZO Migration Resolution Intersection of Fresnel Zones Intersection of Fresnel Zones Vertical Res. = Near-Offset Traces

  24. ZO Migration Resolution Intersection of Fresnel Zones Intersection of Fresnel Zones Horiz. Res. = Far-Offset Traces

  25. Why is Pt. Scatterer Response of Migration a Blurred Version of Point? Lr d = Lr but Migration: Migration Section = Blured Imageof r Migrated Section Data T m = L d

  26. Seismic Section 12 km Time

  27. 0 km 3 km 0 km 7 km

  28. Migration Least Squares Migration 0 km 3 km 0 km 7 km

  29. Seismic Imaging Course • Kirchhoff & Beam Migration • Phase Shift-Like Methods • Reverse-Time Migration • Full Waveform Inversion

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