垦71地区多波采集方法研究及应用效果

多年来,胜利探区多波多分量地震采集所得资料的信噪比和分辨率较低,无法取得较好的应用效果.为此,以胜利垦71区块为先导实验区开展了多波采集方法研究.首先,通过单点三分量检波器与常规检波器小面积组合分析了该区转换波发育情况,认为该区转换界面较强,转换波特征明显,转换横波速度约为纵波速度的1/2;然后,通过数字三分量检波器的室内各种组合研究,进行了超线元叠加,由此可以有效地改善资料的信噪比,并对分辨率基本没有影响;最后,利用三分量检波器扩展排列进行转换波最佳偏移距的设计,通过垂直排列追踪放炮进行最佳非纵距设计,从而得出该区多波采集的最佳观测系统参数.通过上述合理的设计和多项试验研究,在垦71地区多波采集中,数字检波器Z分量剖面的频率优势非常明显,分辨率明显高于常规检波器的纵波剖面,对于搞清小断层及微幅度构造具有重要的意义;同时,转换横波能量强、信噪比和分辨率高,使多波采集取得了较好的效果.

The multi-wave seismic acquisition method and applied result in Ken 71 area

The S/N ratio and resolution of multi-wave multi-component seismic acquisition in Shengli prospect area are both lower several years,so the applied effect is not good.Therefore,we study the multi-wave acquisition techniques in Ken 71 area as the leading tentative zone.First,by analyzing the distribution of converted-wave with the help of single three-component geophone and conventional receivers area arrays,we obtain that the reflection of the converted interface is strong,and the feature of converted-wave is obvious,and the ratio of VS/VP is about 1/2;then,by doing the various array analysis of digital three-component geophone in laboratory,we stack the super-bins,and effectively improve the S/N ratio with little effect on resolution;finally,we use extended array of three-component geophone to design the optimum offset for converted-wave and use tracing shot perpendicular to the array to design the optimum off-line distance,and obtain the optimum layout parameters of multi-wave acquisition in the area.With the above reasonable design and various experiment studies in Ken 71 area,we obtain that the resolution of Z component section for digital geophone is obviously higher than that of P wave section for conventional receiver,which has great meanings for the identification of mini-fault and micro-structure; meanwhile,the strong energy of the converted waves,high S/N ratio and resolution make we acquire preferable effect in multi-wave acquisition.