| Popis: |
Summary Surface-consistent data auto-convolution involved in the modeling of surface related multiple reflections (SRME) does not apply easily to Ocean Bottom Survey data unless surface data is available along the OBS shooting locations, or if the receiver distribution allows for wavefield continuation. For cases where only OBC data are available, and in situations with extremely sparse receiver distributions, 3D SRME can still be achieved by using 3D wavefield multiple modeling (WFM SRME). With this method, surface-related multiples are built by modeling the bounces of primaries and multiples within a migrated section representing any arbitrary 3D reflectivity model. Unfortunately, migration of up-going waves from OBS data suffers from the sparseness of the receiver distribution, thus resulting in blanks along the seafloor reconstruction because of the lack of fold and inapplicability of the imaging condition. Instead, down-going first-order multiples can be easily separated from the data after calibration and P-Z differentiation. This data can then be migrated by using the image of the receiver location with respect to the surface of the sea. This image is unambiguous, and allows for a better illumination and imaging of the seafloor, suitable for WFM SRME. This migration method, followed by WFM SRME, has been successfully applied on real OBS (node) data. Results are shown below.. |
