Research On Vibroseis Acquisition Technology In Dunhuang Basin

Characterized as “safe,environment friendly,economical,good quality”,vibroseis acquisition is suitable for many exploration areas.The excitation frequency and energy is manageable,which is good for the optimization of wavelet,thus can improve the quality of the seismic data.Large-tonnage vibroseis is widely used in western China in recent years,which has not only improved the acquisition efficiency but also the data quality.However,in Dunhuang area,vibroseis acquisition was carried out at an early stage,the acquisition equipment was outdated and the method demonstration was insufficient.There wasn't an efficient vibroseis acquisition technology which was specifically suitable for this area and the data acquired were of low quality.Based on geological background and existing seismic data,this paper focused on the study and application of vibroseis in Dunhuang Basin and concluded that the exploration of the middle-lower Jurassic in Dunhuang Basin should emphasize the suppression of noise and the improvement of the signal to noise ratio.After discussion of the acquisition geometry and receiving mode,an acquisition geometry design with wide-line small group interval,high coverage,large offset,areal array reception along the line was formed.Besides,low-frequency sweep technique for deep strata and vibroseis quality monitoring technique was developed.Vibroseis sweep design software and quality monitoring and working condition analyzing software were developed.A set of vibroseis acquisition technology suitable for Dunhuang Basin is formed,which solved the problem of weak reflection,little reflection information and poor deep strata imaging.Data with strong energy,high signal to noise ratio and rich deep strata reflection information were acquired by using this technology.The data quality was greatly improved,especially the quality of deep-layer imaging.Further study and wider application is needed to improve the technology.