准噶尔盆地两种不同高密度地震方法对比

Comparison of two different high-density seismic technologies in Junggar basin

准噶尔盆地主体为沙漠覆盖,周缘分布有砾石、农田、黄土及砂土.近几年来,中国石油在准噶尔盆地大力推行“两宽一高”地震技术,其核心为利用自主研发的低频可控震源,采用滑动扫描等高效采集技术,实现了宽频带、宽方位、高密度地震;中国石化在准噶尔盆地采用了炸药激发的高密度地震技术.本文在对两种高密度地震方法采用的观测方式、激发方式、接收方式进行对比的基础上,对两种不同高密度地震技术得到的地震记录、针对性处理技术、叠加及成像效果进行了对比研究,研究发现:炸药震源激发高密度地震单炮信噪比高,12.5 m×12.5 m面元、覆盖次数400次就能达到最佳成像效果,可控震源单台单次高效激发资料信噪比低,同样面元下,覆盖次数1000次以上才能达到最佳成像效果,研究结论对准噶尔盆地高密度地震方法选择具有指导意义.

Junggar basin is mainly covered by desert,with gravel,farmland,loess and sand distributed around.In recent years,China National Petroleum Corporation(CNPC)has implemented the Broadband,Wide-azimuth and High-density(BWH)seismic prospecting in Junggar basin.The technology of self-developed low-frequency vibroseis and the high-efficiency slide sweeping seismic acquisition are the keys of the BWH acquisition.The other high-density seismic prospecting way is explosive-based acquisition by Sinopec in this area.Based on the comparison of two high-density seismic technologies on geometry,shot and receiving,this paper makes a comparative study in field records,processing technique,stack and imaging sections.Benefit from high S/N on field record,a geometry of 12.5 m×12.5 m bin size,400-fold is sufficient for best imaging when explosive shot.While a geometry of 12.5 m×12.5 m bin size requires 1000-fold at least to obtain equivalent imaging due to decreased S/N on high-efficiency vibroseis shot.This comparison pointed out a guideline for high-density seismic acquisition in this area.