Research On Attenuation Method For Complex Deepwater Multiple In South China Sea

At present,the first offshore exploration has been basically completed,the development of seismic exploration is the deep and ultra deep waters.Deep water areas in china are mainly distributed in the South China Sea,in which many oil and gas fields have been found in succession,thus requirements of the deep water data processing,in which multiple attenuation is a very important step,are also getting higher and higher.The topic of multiple wave attenuation has been a hot issue which is always debated among scholars,and it is also a difficult problem in marine data processing all the time.Seismic data in deepwater shows critical sea surface related multiple,the energy of which is very strong and seriously affects the quality of the seismic image,then affects the interpretation accuracy,especially in complex seabed area,complex multiple causes and types increases the processing difficulty.Therefore,in order to improve the imaging quality,the formation mechanism of multiple and the methods of attenuation for deep water data are deeply studied.It is essential to summarize a set of effective methods for deep water multiple wave attenuation.In this paper,the present situation of multiple wave attenuation at home and abroad is investigated;further the definition and types of multiples are generalized;a deep research on the formation mechanism and characteristics of multiple waves;through the detailed analysis of the actual data and model,and summarizes the recognition method of multiple;ghost as a multiple wave,in this paper has been carried out targeted research.On this basis,simple and complex geological models are established,and forward multiple simulation and single shot recording are carried out by acoustic wave equation.First,the forward data is detailedly analyzed to understand the characterristics of multiple,then it is researched that principle and adaptability of multiple attenuation in different ways,which are applied to forward data for detailed comparison and analysis to develope the most effective deep-water multiple attenuation process,final through the application of actual seismic data in the South China sea to test its effect.The model and actual data processing results show that the use of combining attenuation process(ghost attenuation,wave equation based prediction and subtraction,high precision Radon domain multiple attenuation,residual diffraction multiples attenuation)has achieved good results,deep water multiple is attenuated,the primary wave that was covered by multiple is enhanced and signal to noise ratio of data is improved.