Overpressured sedimentary basins are ubiquitous and extensively distributed in marine areas.They typically possess favorable conditions for hydrocarbon accumulation,thus holding considerable significance for guiding hydrocarbon resource evaluation and exploration deployment.Velocity serves as a key parameter for research on overpressure distributions.The increasing demands for higher accuracy in overpressure distribution prediction impose higher requirements on the accuracy and quality of seismic velocities.Compared to well patterns in land areas,the more sparse well patterns in marine areas lead to insufficient well constraints on seismic velocities,requiring a comprehensive reliability evaluation.Additionally,seismic velocities obtained from conventional velocity analysis or modeling often show insufficient resolution.Therefore,this study proposed a high-density bispectral velocity picking method under the theoretical framework of high-order normal-moveout(NMO) based on uncorrelated parameters.The proposed method can obtain higher-resolution seismic velocity volumes for favorable target areas,providing an effective approach to exploring overpressure distributions in marine basins.This study first presented the theoretical principles of high-order NMO correction.Subsequently,it demonstrated the application of the proposed method in a specific exploration area in the East China Sea.The practical application suggests that seismic velocity volumes subjected to high-order NMO correction can effectively reflect subsurface overpressure distributions,showing promising prospects in the research on overpressure distributions in marine areas.
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