Research On Linear Interference Suppression Method Based On Lifting Wavelet Transform

With the development and application of pre-stack migration technology,the focus of seismic data processing has changed from post-stack processing to pre-stack processing,compared with the post-stack offset,the pre-stack migration has higher requirements on the seismic data signal to noise ratio.As we all know,there are many different types of interference waves in the original seismic data.Among them,linear interference is a common interference wave.The linear interference has large amplitude energy,strong spatial correlation,stable apparent velocity and close frequency to reflection wave frequency,which seriously affects the reflected wave imaging and interferes with the seismic interpretation work.Therefore,suppressing linear interference has become an important task in seismic data processing.In the existing linear interference suppression methods,such as F-K filtering,K-L transformation,median filtering,due to the limitations of the method itself,effective signal leakage or incomplete noise suppression often occurs,so it is difficult to obtain satisfactory results in real seismic data processing.Therefore,aiming at the linear interference problem in the original seismic data,the linear interference suppression method based on lifting wavelet transform is studied to eliminate linear interference waves and improve the signal-to-noise ratio of pre-stack seismic data,which lays a foundation for pre-stack migration processing.Firstly,the paper starts with the principle analysis of traditional linear interference suppression method,summarizes the advantages and disadvantages and applicability of traditional methods,and then based on previous research,proposes a method based on lifting wavelet transform to suppress linear interference,and elaborates the principle and scope of application of lifting wavelet transform to suppress linear interference in detail.The method utilizes the local coherence of the seismic signal,combined with the idea of the dip scan,flattens the linear interference events to the horizontal events,extracts the linear interference,and then subtracts the linear interference signal from the original seismic signal to achieve the suppression of the linear interference.By improving the linear interference suppression methodbased on lifting wavelet transform,the technique of automatically tracking the linear interference events is combined with the lifting wavelet transform,and the direction is tracked by the strong correlation between linear interference traces.At the same time,the covariance measure criterion is used,which expands the scope of the method and reduces the damage to the effective signal.The feasibility and applicability of the paper method are verified by applying it to model and actual data.The comparison with the traditional methods shows that the proposed linear interference suppression method based on lifting wavelet transform can effectively suppress the linear interference in the seismic record,and can better maintain the seismic characteristics of the effective signal,thus greatly improving the signal-to-noise ratio of seismic data.Finally,the paper also looks forward to the method and provides direction for future research.