The Angle Domain Seismic Beam-forming Method Based On Singular Value Decomposition

In the field of seismic exploration,the original seismic data collected from deep and complex areas has low signal-to-noise ratio(SNR),which seriously affects the processing and interpretation of seismic data.In order to improve the SNR of such seismic data,Time Seismic Beam-forming Based on Receiver Array(TSBBRA)method is proposed.However,when the SNR of seismic data is very low,TSBBRA method requires a large number N of superimposed records to satisfy the requirements of seismic interpretation.It has been learned that the larger the N is,the narrower the beam is,and the beam is too narrow to cover the entire array of detectors,resulting in signal distortion outside the effective beam width.In addition,the noise suppression of the TSBBRA method is not uniform.If the requirement of seismic interpretation is high,the application effect is not good.Therefore,in order to improve TSBBRA method to the above problems in dealing with low SNR seismic records,this paper presents an angle domain seismic beam-forming method based on singular value decompositio n(ADSBSVD).ADSBSVD method can enhance the energy of the whole reflection same phase by the angle domain beam-forming method,and suppress the coherent noise and random noise by SVD method to extract the coherent information in the seismic record.In this paper,the research on ADSBSVD method is carried out in four aspects: theory,method,numerical simulation and field experiment.The main research content is as follows:Firstly,the beam-forming theory is expounded,and the theory of seismic beam-forming method at the source end and the receiving end are respectively studied.In addition,the theoretical basis and the denoising principle of SVD method are also respectively discussed.The principle of the angle domain seismic beam-forming is studied.The characteristics of the angle domain beam and the influence of the relevant parameters on the characteristics of angle domain beam are deduced.We analyse the factors affecting SVD filtering effect and the influence of SVD on angle field beam direction for noise.Finally,the principle of the angle domain seismic beam-forming based on singular value decomposition is proposed.Then,ADSBSVD method is described.The key steps of ADSBSVD method are designed by analyzing the characteristics of noise and signal in seismic record.For the key steps in the process,the detailed implementation method and calculation process of the key steps are given.Secondly,the numerical simulation of ADSBSVD method is carried out.We study the seismic response of ADSBSVD method on the horizontal layered model,fault model and low velocity orebody model.And the detailed processing of seismic records is given by ADSBSVD method.The quantitative analysis result shows that ADSBSVD method can significantly improve the SNR of seismic record.Finally,field test is performed on the ADSBSVD method.We use ADSBSVD method to deal with the seismic records collected in the field,and quantitatively analyze the processing result.The results of the treatment show that ADSBSVD method can effectively improve the quality of low SNR seismic records,thus proving the effectiveness of ADSBSVD method in the practical point of view.