Research On Ghost Attenuation Method For Broad-band Marine Seismic Data

With the acceleration of global industrialization,there are great opportunities for offshore oil and gas exploration and development.Complex underground geological structure and stratigraphic conditions put forward higher requirements for exploration accuracy,exploration methods and corresponding data processing techniques.In order to accurately obtain high-precision and high-resolution reflection information of exploration target formation and achieve more delicate imaging,broad-band acquisition and processing techniques have been greatly improved in recent years.the broad-band acquisition method has gradually developed from upper and lower cables,curved cable and straight cable to deep depth cable acquisition,and broad-band has gradually matured,gradually replacing conventional acquisition,becoming the mainstream acquisition method in the international geophysical prospecting market.In this paper,based on many years' experience in offshore oil seismic operation,the methods of marine seismic construction were discussed,some key equipment for marine seismic exploration were briefly introduced.And also systematically studied the current situation of broad-band acquisition and processing at home and abroad,and discussed the progress of acquisition and construction methods in the international geophysical prospecting market in recent years.Based on the basic principle of seismic exploration,the generation mechanism of ghost wave,the classification of ghost wave and its representation and characteristics in actual seismic data were studied.Related research has been carried out on the processing methods of the marine seismic data in recent years.Finally,the frequency domain high-resolution Radon transform was selected as the main research object,which is with good applicability to various broad-band acquisition types.The ghost attenuation is performed on the most representative marine broad-band seismic data acquired by three broad-band acquisition methods.Through the analysis and comparison of broad-band processing before and after shot record,shot record spectrum,CDP gather,stack section and stack spectrum,it can be seen that both source ghost and receiver ghost have been attenuated to a great extent.After attenuation,ghost wave information has been eliminated obviously,which makes the underground reflection horizon clearer and the continuity of primary reflection wave coaxial more reliable and clear.At the same time,notch energy in spectrum analysis has been significantly improved,basically eliminating the influence of notch on seismic data.Broad-band processing not only broadens the low-frequency component of seismic data,but also broadens the high-frequency component of seismic data.Especially,the energy of low-frequency component has been significantly enhanced.The low-frequency of seismic data can be as low as 3 Hz,which is very important for seismic inversion results and can obtain more reliable inversion results.By comparing the processing result,the validity of this method is verified.It can be seen that this method can effectively eliminate ghost waves,enhance notch spectrum and broaden the frequency bandwidth of marine seismic data.This method has achieved good processing results in the application of actual marine seismic data.