Research Of 4C-OBC Seismic Data Processing Technology

Weixinan area is an important oil and gas exploration field in the north of the South China Sea.After years of exploration,the exploration target has turned to small and complex structure.The towed stream 3D seismic data already re-processing several times,the imaging of target still poor,can not meet the needs of exploration and development;in this case combined with the acquisition environment,carried out 4C-OBC seismic exploration.Due to the lack of technology accumulation,the 4C-OBC seismic data encountered several problems such as geophone and hydrophone combination,OBC multiple suppression,wide azimuth seismic data reconstruction and conversion wave data processing and utilization.In this paper,the following research is carried out: 1)The multi-wave suppression technique and its advantages and disadvantages are analyzed in detail.Combined with the characteristics of 4C-OBC data,the OBC-SRME multiple suppression technology,based on the plane wave field extension of the OBC shallow water layer multiple suppression technology.2)Research and analysis of the OBC acquisition system of Weixinan area and the reconstruction of irregular sampling data;3)Some key technologies such as conversion wave theory,wave equation theory and conversion wave processing process are studied,such as horizontal component rotation,CCP gather sort,converted wave imaging and so on.Based on the above research contents,this paper has made the following important research results as follows:1)The OBC shallow water layer multiple compression technique based on the plane wavefield continuation is developed using the periodic and the propagation of multiple.2)COV interpolation and five-dimensional interpolation are used to reconstruct the 4C-OBC seismic data in the South China Sea,and the wide azimuth characteristics of the 4C-OBC seismic data are better preserved,which is favorable for prestack inversion,azimuthal anisotropy analysis,And so on.3)The three-dimensional converted wave seismic data processing in the South China Sea was carried out for the first time,and a complete 4C-OBC process was established to provide a template for the 4C-OBC data processing in the future.Based on the above research results,the 4C-OBC seismic data of WeixiNan are processed,which solves the problem of OBC multi-wave suppression,wide azimuth characteristic data reconstruction,common conversion point gather extraction,conversion wave static correction in 4C-OBC data,Converted wave imaging and other key issues.Compared with the data of the streamer,the 4C-OBC data quality was improved greatly in he middle and deep signal-to-noise ratio,the complex fault block imaging,the wave group characteristics and other methods have a substantial increase,meets the oilfield development needs.The conversion wave data processing has made breakthrough progress,and the converted wave results have achieved good results in the middle and deep imaging,signal to noise ratio and so on.This dissertation contains 153 figures,2 tables,and 177 references.