Research On Multiple Wave Suppression Method In Nanpu No.2 And No.3 Structural Slope Area

In marine seismic exploration,high-quality and low-noise marine seismic data is the premise of accurate oil and gas exploration in the sea area.The abnormal development of multiples in marine environment has seriously affected the imaging of underground geological structures.Multiples will cause migration and arc drawing in the imaging section and form a structural illusion,which will seriously interfere with the fine seismic interpretation.Therefore,how to effectively suppress multiples and retain an effective signal is the key to marine seismic exploration.This thesis systematically investigates and summarizes the technical means of multiple suppression.Combined with the characteristics of multiples in Nanpu 2 and 3blocks,a method combining SRME method with high-precision parabolic Radon transform is proposed.The traditional Radon transform uses the regional difference of radon spectrum distribution between multiple and primary to separate multiple and primary,but this characteristic difference also makes this filtering method have some limitations and easy to damage some effective wave components.High precision Radon transform can reduce the leakage of radon spectrum and improve the convergence of radon spectrum,so as to improve the effect of Radon transform.SRME method is a data-driven technology,which does not need a priori and a posteriori information.Through the method of data reconstruction,the multiples are accurately predicted,and then eliminated by adaptive subtraction.It has the advantages of more accuracy and fidelity.This method requires high regularity of the observation system,and can only remove free surface multiples.Based on the analysis of the adaptability of the two methods and the combination of the two methods,a combined suppression method of SRME and high-precision Radon transform is proposed.The application of multiple suppression effect in Nanpu 2 and 3 blocks shows that the combination method can suppress the main multiples in this area,and finally improve the quality of stack section and imaging section.