Research On Deghosting Algorithm For Variable-depth Streamer Seismic Data In Tau-p Domain

Marine seismic exploration has unique advantages over land seismic exploration.It has the characteristics of high efficiency,low cost,and quick results,and marine seismic data usually have high signal-to-noise ratio.However,marine seismic exploration also faces many problems,The widely-existed receiver ghost not only leads to notches in spectrum of seismic data,but also forms fake events in the seismic record,it will finally reduce the resolution of the seismic record.In order to obtain seismic data with wider frequency bandwidth and higher signal-to-noise ratio,marine broadband seismic exploration has gradually become a hot research area now.As an important technology in the marine broadband seismic exploration,VDS acquisition technology is widely used in marine seismic exploration.As the depth of receiver varies with the offset,the wave field captured by VDS is more abundant.In addition,receivers' configuration makes a time difference between ghost and primary and also results in notch diversity.So it provides the possibility of deghosting to obtain true broadband seismic data.This paper focuses on the study of forward modeling,VDS seismic exploration mechanism and the deghosting method.Firstly,the ray tracing method was used to forward modeling the VDS seismic record,then the characteristics of the VDS seismic wave field and the effect of receiver ghost on the primary and seismic record were analyzed.The formula of the frequency characteristics of ghost was deduced,and the influence of different receiver depths on the spectrum of seismic data was discussed.Then,the time-difference relationship between primary and ghost was studied based on the theory of plane waves.By analyzing and improving the traditional linear Radon transform,and introduce the time difference to Radon formula,a deghosting algorithm based on plane wave decomposition was studied.The basic flow of receiver ghost suppression for VDS seismic data was established.Finally,the high-resolution Radon transform based on compressive sensing theory framework was studied Combining with the traditional deghosting algorithm based on forward and inverse Radon transform,it can eliminate aliasing and truncation effects,improve the resolution of results in Radon domain,and improve the signal-to-noise ratio of the deghosting results..The deghosting algorithm based on plane wave decomposition was tested on 2D horizontal layered medium model,3D horizontal layered medium model and real data.The algorithm was proved feasible and effective.Through spectrum analysis,it can be found that the notches of the processing result is compensated and the bandwidth of the seismic data is broadened.