2005 RESEARCH UTAM ACCOMPLISHMENTS AND 2006 GOALS

  1. Migration Deconvolution
    • RESULT: Sergio Perez and Guoan Luo test poststack MD on 3D Pemex data. Some parts of the MD image show clear improvement in lateral resolution. Some parts seem to have lost low wavenumber information. Guoan Luo reduces computational cost of MD by a fast MD approximation.
    • IMPLICATION: We need prestack migration gathers to implement prestack MD.
    • PROBLEMS: Why did we lose low wavenumber infromation?
    • 2006 GOALS: Improve MD performance and test prestack MD on prestack Pemex data.

  2. Multiple Migration
    • RESULT: Salt flank imaging with interbed multiples. Interferometric wave equation migration of multiples in 3D VSP data. Land data results show much wider coverage than conventional VSP migration, but identifying the strong near-surface reflector is an issue. One land data test showed degraded S/N ratio.
    • IMPLICATION: 3D interferomteric migration by wave equation is a milestone. Sparse VSP geophones suggest wave equation imaging cheaper than Kirchhoff imaging.
    • PROBLEMS: Need further field data tests.
    • 2006 GOALS: Multiple migration of 3D VSP data.

  3. Seismic Interferometry
    • RESULT: Several new theories: 1). Refraction interferometry developed to redatum surface sources+receivers to be on refractor, 2). Interferometric Fermat's principle and tomography for PS waves, 3). Interferometric redatuming of VSP data to be CDP data and vice versa, 4). Theory developed for estimating transfer function of a scattering layer. 5). Interferometric prediction of surface waves and least squares subtraction, 6). Cheaper version of interferometry known as specular interferometric imaging. 7). Earth as a vibroseis, 8). Synthetic test suggests that top of salt might be better imaged by CDP multiples than by CDP primaries.
    • IMPLICATIONS: Opens up new fields in seismic imaging. Will try to solve tough practical problems. It appears that some form of interferometry should be applied to many VSP marine data sets to optimize imaging of subsurface reflectivity. Much wider coverage than conventional VSP imaging. We still have not found the killer app. for CDP interferometry. Surface wave filtering by interferometry looks promising.
    • PROBLEMS: Some methods are completing initial testing phase for field data. Cross talk is still an issue. Solving it will enhance multiple images obtained from CDP data.
    • 2006 GOALS: Test above methods on more data sets. Assess effectiveness of other methods on field and synthetic data. Minimize cross-talk in interferometric imaging.

  4. Early Arrival Waveform Imaging
    • RESULT: Waveform inversion test on ARAMCO data shows big improvement in stacked image compared to brute stack image.
    • IMPLICATION: Synthetic and field data results are encouraging.
    • PROBLEMS: Processing is very time consumming.
    • 2006 GOALS: Full tests on Saudi, Inco data and other data. Possibly elastic inversion.