Kaskida is a large three-way reservoir truncated by a salt weld and lying underneath a complex salt body. Inhomogeneous illumination from the complex overburden, which distorts the amplitude of reservoir reflectors and generates migration artifacts, has a detrimental impact on the seismic image at the reservoir level. The application of least-squares RTM (LSRTM) at Kaskida field demonstrates that it can effectively improve the signal-to-noise ratio (S/N) of the subsalt image by reducing migration artifacts, and it can also improve the reservoir amplitude fidelity by compensating for illumination effects caused by the overburden velocity and acquisition geometry. We further demonstrate that a more correct velocity model derived from reflection FWI (RFWI) improves LSRTM results by providing a better raw RTM image and more accurate illumination compensation. Finally, we compare common-image gathers (CIGs) from well-data synthetic modelling, raw RTM, and LSRTM and conclude that LSRTM improves the AVO response over raw RTM because of the offset-dependent illumination compensation and reduction in migration artifacts.


Article metrics loading...

Loading full text...

Full text loading...


  1. Guitton, A.
    [2004] Amplitude and kinematic corrections of migrated images for nonunitary imaging operators. Geophysics, 69(4), 1017–1024.
    [Google Scholar]
  2. Lecomte, I.
    [2008] Resolution and illumination analyses in PSDM: A ray-based approach. The Leading Edge, 27(5), 650–663.
    [Google Scholar]
  3. Schuster, G. T.
    [1993] Least-squares crosswell migration. SEG Technical Program Expanded Abstracts, 12, 110–113.
    [Google Scholar]
  4. Tarantola, A.
    [1987] Inverse problem theory: Methods for data fitting and model parameter estimation. Elsevier Science Publishing Company.
    [Google Scholar]
  5. Wang, P., Gomes, A., Zhang, Z., and Wang, M.
    [2016] Least-squares RTM: Reality and possibilities for subsalt imaging. SEG Technical Program Expanded Abstracts, 35, 4204–4209.
    [Google Scholar]

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error