CHARACTERISTICS OF SEISMIC MULTIPLES ON THE LAOSHAN UPLIFT AND THEIR SUPPRESSION METHOD

Multiple suppression is an essential procedure in marine seismic data processing. On the Laoshan Uplift of the South Yellow Sea Basin, The Mesozoic was almost completely denudated since the strong Indo-China movement, and the Cenozoic directly covers the Paleozoic. There are three strong reflection coefficient interfaces, i.e. the sea surface, the sea bottom and the unconformity between the Cenozoic and the Paleozoic. They lead to the formation of various multiples, because of the interference of multiples. As the result, the primary reflection from the Meso-Paleozoic boundary is hard to be effectively identified. Therefore, multiple suppression is the key step to Meso-Paleozoic seismic imaging. Based on the theory of simulation and practical data analysis, we summarized the characteristics of multiples of the area. It is found that there are three main types of multiple in this sea area. They are the surface-related, long period and refraction multiples. These types of multiple are suppressed with appropriate methods described in this paper. The authors introduced the main principle first and then evaluated the applicability of these methods. The removal and migration results of multiples from the south-north survey line across the Laoshan Uplift show that the multiples are suppressed thoroughly with the integrated suppression methods described in this paper and the quality of Meso-Paleozoic seismic imaging is improved.