Research On Phased-array Vibrator System Excitation Technology And Noise Suppression Method

Seismic exploration plays an important role in the fields of geological investigation and energy exploration.It is one of the main exploration methods to study the structure of underground strata and geological information.In recent years,with the deepening of exploration,the exploration area is gradually turning from shallow layer to deep layer.The geological structure is increasingly complex,which puts forward higher requirements for seismic data acquisition,processing and interpretation technology.All kinds of noise interference also have a serious impact on the interpretation and recognition of effective information.In order to better meet the demand of exploration,the research focus of seismic exploration is shifting to the target of high-precision seismic exploration,so as to obtain higher quality exploration data.As a basic part of seismic data acquisition,source is directly related to the exploration effect of seismic exploration,and has always been one of the important research contents of high-precision seismic exploration.Phased-array vibrator system excitation technology can be more flexible to meet the needs of high-precision seismic exploration,it can effectively enhance the lighting energy in specific direction,improve the signal to noise ratio of seismic data of geological target,so as to obtain valuable geological information more effectively.Noise suppression is also one of the main research tasks of high-precision seismic exploration.By eliminating the noise in seismic data with more effective techniques,the signal-to-noise ratio,clarity and fidelity of seismic data can be greatly improved,which is also conducive to the subsequent analysis of seismic data and the further understanding and recognition of geological structure.In recent years,new breakthroughs have been made in seismic signal analysis based on multi-scale geometric analysis theory.Using multi-scale geometric analysis theory to denoise seismic data has become a very meaningful scientific research direction and has a very wide application prospect.The content of this thesis is the research on seismic simulation of phased-array vibrator system and seismic noise suppression.The main research work is as follows:(1)Based on the principle of directional excitation of phased-array vibrator system,numerical simulation and illumination analysis of phased-array vibrator system,the optimization problem of working parameters of phased-array vibrator system excitation technology is studied,and the influence of different working parameters on seismic acquisition is analyzed,so as to find a set of optimal working parameters,which can greatly improve the accuracy of field exploration and improve the imaging quality;(2)Introduced the noise types and corresponding propagation rules in seismic data of phased source and the denoising model of seismic data based on sparse representation theory.Then,a coherent noise suppression method based on non-subsampled Shearlet transform and a random noise denoising method based on non-subsampled Shearlet transform combined with BM3 D are proposed for the seismic data noise of phased-array vibrator system,and applied to synthetic seismic data and actual seismic data for verification.It is of great practical significance to provide effective help for subsequent seismic data processing and interpretation.(3)In order to study the practical application effect of the phased-array vibrator system excitation technology and verify the feasibility and science of improving the seismic exploration effect,a field exploration test was carried out in a pasture in Chaganhua Town,Songyuan City,Jilin Province,and the seismic data collected based on the phased-array vibrator system excitation technology were processed,and the corresponding horizontal stack seismic time profile was given.The superiority of directional excitation technology of phase controlled source is evaluated.