The Study On The Critical Processing Technique Of Low SNR Seismic Data On Complex Surface Of Wushi Depression

Wushi Depression,which belongs to Beibuwan Basin,is one of the important extraterritorial exploration areas in Jiangsu Oilfield.Multi-stage igneous rock eruption coverage and late weathering lead to complex near-surface structure and low signal-to-noise ratio of seismic data,which bring great difficulties to seismic data acquisition,processing and interpretation.Therefore,it is necessary to conduct in-depth study on seismic data processing methods and flows in this area.Based on the analysis of the characteristics of complex surface seismic data in Wushi depression,this paper studies the static correction,denoising and velocity analysis methods for low signal-to-noise ratio seismic data in this area.Firstly,through the statistical analysis of seismic data,the reasons affecting the quality of data are obtained,and the corresponding research countermeasures are put forward.Secondly,the first break wave pretreatment method is used to improve the accuracy of first break wave pick-up and ensure the application effect of tomographic static correction.For seismic data collected from loose basalt and laterite,the comprehensive optimization iterative static correction method is adopted to basically eliminate the influence of static correction and improve the imaging effect of stacked sections.Then,in order to improve the signal-to-noise ratio of seismic data in Wushi depression,the SVD denoising method is applied to remove linear interference,random interference and multiple waves.Finally,taking the dominant signal velocity spectrum analysis method as the core,the interactive velocity analysis method and the along-layer velocity analysis method are applied comprehensively,which effectively improves the accuracy of velocity analysis and achieves good results in practical application.The results show that the static correction method,denoising method and velocity analysis method proposed in this paper improve the signal-to-noise ratio and resolution of seismic data in Wushi Sag,and form an effective processing flow for seismic data in low signal-to-noise ratio areas with complex surface.