Concepts and Applications in 3D Seismic Imaging

(2007 SEG/EAGE Distinguished Instructor Short Course)

by Biondo Biondi

Duration: One day

Summary:
Seismic images are the basis of crucial exploration, development, and production decisions. Optimal use of these images requires a full understanding of the seismic imaging processes that create them, from data acquisition to the final migration. The primary objective of this course is to provide a broad and intuitive understanding of seismic imaging concepts and methods that enables geoscientists to make the appropriate decisions during acquisition, processing, imaging, and interpretation projects. Another objective is to expose the audience to current trends in imaging research and empower them to adopt new technologies quickly.

Course Outline:
The course is organized in four lectures. The first lecture introduces the fundamental concepts of seismic imaging. The remaining lectures focus on the solutions to three crucial problems encountered in practical application of 3D seismic data: 1) choice of the most effective migration algorithm, 2) estimation of the velocity model, and 3) poor image quality caused by irregular and inadequate data spatial sampling and incomplete subsurface illumination.

  1. Introduction to 3-D seismic imaging
    • Commonly used data-acquisition geometries and their impact on imaging
    • Seismic imaging as a data focusing process and Kirchhoff migration methods
    • Partial prestack migration and other approximations to full prestack migration
    • Principles of wavefield-continuation equation migration
    • The relationship between seismic velocity and migration
  2. A user's guide to the migration toolbox
    • Time vs. depth migration
    • Kirchhoff depth migration
    • Depth migration by wavefield-continuation
    • Anisotropic migration
    • Current trends in depth migration (beam, plane-wave, and reverse-time migration)
  3. The never-ending quest for the perfect velocity model
    • Basic methods for velocity estimation (velocity spectra, Dix equation)
    • Velocity estimation and complex structure
    • Principles of reflection traveltime tomography
    • Migration Velocity Analysis (MVA)
    • Introducing geological knowledge in the MVA process
    • Current trends in MVA (velocity scans, residual migration, wave-equation MVA)
  4. Imaging, aliasing, and incomplete subsurface illumination
    • Spatial aliasing and imaging artifacts caused by inadequate spatial sampling
    • Avoiding aliasing in Kirchhoff migration and continuation migration
    • Imaging artifacts caused by irregular data geometry and incomplete illumination
    • Illumination maps: how to use and not abuse them
    • Application of approximate regularized inversion to imaging enhancements
      • Data-domain methods (data geometry regularization)
      • Model-domain methods (imaging by least-squares migration)

Instructor Biography:
Biondo Biondi