基于深度偏移角道集共聚焦分析的炮域炮检距矢量片优化叠加方法

A shot domain offset vector tile optimization stack approach based on depth migration angle gather focal-beam analysis

复杂构造地区断块和高陡构造发育,相比于平缓地层,高陡构造区域地震照明有限,数据信噪比较低,全偏数据参与叠加对提高成像信噪比不利。由于区域构造特征的差异性,不同高陡构造带对应的反射具有明显的方向性,不同炮检距(即入射角)段的反射信号具有明显分带特征。据此,在炮域深度偏移角道集上进行炮检距矢量片(Shot Domain Offset Vector Tile,SVOT)划分,有效分离出不同倾向、不同倾角界面的深偏数据。采用共聚焦分析方法,分析各SOVT叠加剖面的信号聚焦特性;根据其成像清晰度属性,进行SOVT剖面加权优化叠加,突出有效信号,改善高陡界面的成像信噪比。理论模型与实际数据测试验证了该方法的有效性;同时,它可依托商业软件深度偏移模块运行,只需额外增加少量运算,适于工业化推广。

Fault blocks and high-steep structures are developed in tectonic complicated areas.Compared with gentle formation,the high-steep tectonic areas are characterized by limited seismic illumination and low signal-tonoise ratio of seismic data.Therefore,the participation of fully biased data in stacking is adverse to improving imaging signal-noise ratio.Due to the difference in regional structural characteristics,the reflections corresponding to different high-steep tectonic zones are directional,and the reflection seismic phases of different offset(i.e.,incident angle)segments have obvious regional characteristics.This paper divides depth migration angle gathers into shot domain offset vector tile(SOVT),thus effectively separating the depth migration data with different dip angles interfaces.The focal-beam analysis method is employed to analyze the signal focusing properties of SOVT stacked sections.Then,the weighted optimization stacking of the SOVT profile is performed based on its imaging sharpness attribute to highlight the effective signals and improve the imaging signal-noise ratio on the high-steep interface.The effectiveness of the proposed method is verified through the theoretical model and real data test.Meanwhile,the proposed method can be operated relying on the depth migration module of commercial software with only a few extra calculations required,which is suitable for industrial applications.