Model-based Predictive Deconvolution With Varying Period

The multiples in the seismic records are usually very complicated. Even if attenuated by comprehending all kinds of the existing methods, there are still some residual multiples existing in the seismic data. Because that the attitude and feature of the residual multiples have been obscured, it is more difficult for them to be distinguished and attenuated afterwards. Not only their existence in the seismic data can affect the imaging quality but also they may lead to wrong geological interpretations as well.Aimed to distinguish and attenuate the residual multiples in the seismic data, a new method named Model-based Predictive Deconvolution with Varying Period is developed in this research. Not like as the conventional predictive deconvolution approach does, the method presented in this paper is firstly to distinguish the residual multiples on the migrated section by a ray-tracing manner based upon a built depth-velocity model of the stronger reflecting boundaries. The attenuation processing of the predictive deconvolution with variable periods or variable predictive steps, determined by the travel time(s) of the residual multiples on the section, is then applied to those traces which contain residual multiples in the corresponding imaging gathers. A new migrated section is finally synthesized by using the imaging gathers with the residual multiples eliminated. The experiment processing results of numerical and real data examples demonstrate that the method can not only sufficiently attenuate the peg-leg multiple but also can eliminate the long-period residual multiple to a satisfied result, which may be difficult to be attenuated by the conventional predictive deconvolution techniques.The characteristics of kinds of reverberations or multiples are presented in this paper based upon a comprehensive experiment analysis. The conclusions may have good instructive meanings for real seismic data processing and analysis, especially for the distinction of complex multiples and the attenuation of those with high dip angles.