海南火成岩发育区的三维地震采集技术研究

Research of 3D Seismic Data Acquisition Techniques in Igneous Rock Area,Hainan

海南福山凹陷表层及浅层火成岩异常发育,以及海陆地区的复杂地理环境等因素,导致多次反射波、折射波等干扰波现象非常突出,其结果是地震有效信号成像困难,地震资料分辨率、信噪比低,地震资料品质差。针对火成岩分布区的地震资料采集问题,从分析以往地震采集方法入手,找出采集方法中存在的不足,研究火成岩与地震资料品质之间的关系,针对地质任务要求及目的层反射特点,通过对多个地震采集参数进行论证,并对不同采集方案进行优选,结合本地区特殊地理、地质条件,最终确定了野外观测系统设计理念:大炮检距、高覆盖次数、小面元观测;为保证激发能量和避免多次波干扰,采用在地表风化层和表层火成岩层下激发;不同区域采用不同覆盖次数的灵活多变的采集观测方法,以确保获得高品质的地震资料。

The igneous rock has developed in shallow layer and near-surface layer in Fushan sag of Hainan,and the geological condition is very complex in sea and land areas,these factors lead to multiple waves and refraction waves,it gets difficult to image the seismic data,and the seismic data are characterized by low resolution,low signal-to-noise ratio and poor quality.In order to solve these seismic acquisition problems,this paper firstly analyses the shortages of old acquisition methods to find out the relationships between the igneous rock and seismic data quality.Then according to the features of the target layers,the special geological and geographical conditions in this area,this paper selects the optimization method and demonstrates different acquisition parameters.Finally it ascertains the ideal observation system featuring in big offset,high fold and small binning.In order to guarantee the shot energy,to avoid the multiple waves and to get high quality seismic data,the shot is under the near-surface weathering layer and the igneous rock layer with different folds in different areas.