伊犁盆地伊宁凹陷多次波的形成机理及采集方法研究

Acquisition Method and Formation Mechanism of Multiple Wave in Yining Depression of Yili Basin

伊犁盆地伊宁凹陷侏罗系地层顶部存在2套煤层,导致该地区多次波十分发育,并与下伏多个反射界面的反射波相互干涉,严重影响了目的层的反射品质。利用已往勘探成果建立地球物理模型,基于正演模拟方法进行多次波特征分析,优选地震采集参数,为室内压制多次波处理提供可靠的资料,从而提高深层反射能量,改善资料的信噪比。结果表明,增大偏移距,提高覆盖次数,有利于压制时差特征与一次反射波的差异较明显的全程多次波和部分短程多次波。

There existed 2 sets of coal seams on the top of Jurassic sedimentary strata in Yining Depression of Yili Basin,where multiples were well developed and interfered each other with underlying reflection planes.It greatly impacted the quality of the target zones.Based on forward modeling,it presented a new design method of seismic acquisition geometry to suppress multiple wave interference.It could improve the energy of seismic wave and the signal-to-noise ratio of the deep reflection.The result shows that changing the acquisition parameters,i.e.reducing the receiver interval,increasing the spread length and improving the fold are favorable for suppressing the time difference between the primaries and multiples and improving signal to noise ratio of deep reflection.