Free-surface-related multiple prediction for complex seafloor
LI Xiaozhang1, DENG Yong1, HE Jianwei1, REN Ting1, GU Hanming2
1. Zhanjiang Branch, CNOOC, Zhanjiang, Guangdong 524057, China; 2. Institute of Geophysics and Geomatics, China University of Geosciences(Wuhan), Wuhan, Hubei 430074, China
Abstract:For complex seafloor with complex wavepath,diffracted wave and diffracted multiples,multiple model predicted by SRME method has low signal-to-noise ratio,incorrect dynamic and kinematic information.Multiple prediction method based on the extrapolation of one-way and two-way wave equation was proposed in this paper.Based on wave equation and SRME method,it uses rock physics model to extrapolate the received wavefield,to derive the predicted multiple model.It also uses adaptive subtraction to improve multiple elimination effect for complex seafloor.Model tests and the application in real data demonstrate that multiple model predicted by the method proposed in this paper has higher signal-to-noise ratio and matches better with real multiples in dynamic and kinematic characteristics,compared with that predicted by individual SRME method.Theoretically,it is nece-ssary to know accurate rock physics model when using this method.For the majority of multiples in marine seismic data are free-surface-related multiples,given seawater and seafloor rock physics parameters,the method proposed in this paper can predict the majority of free-surface-related multiples.
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