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Simultaneous Shooting for Sparse OBN 4D Surveys and Deblending Using Modified Radon Operators
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, cp-451-00327
Abstract
Significant gains in productivity (and savings on survey time and cost) have recently been achieved using simultaneous sources with high-density Ocean Bottom Cable geometries. However, where the acquisition is receiver-bound, using sparse Ocean Bottom Node (OBN) arrays for example, the argument for use of simultaneous sources is less compelling. Time and motion analysis for a rolling array of sparse OBN, spaced by 390 m with a 30x30 m shot carpet, shows that time savings of the order of 10 % of the equivalent single-source survey duration should be expected. Although small this may be significant in tightly constrained acquisition seasons. Since time-lapse surveying is the main motivation for many sparse OBN acquisitions, the saving in survey time must be balanced against the risk of additional 4D noise created by simultaneous-source crosstalk. Attenuating crosstalk using a new form of Radon operator implemented with cascaded fx prediction and interpolation as part of a kill-fill process, the level of 4D noise created by simultaneous sources is reduced to an ambient level of 6 %, with a highly randomized character, after imaging.