双反射偏移技术实现礁灰岩油藏断层和裂缝的有效预测

摘要

Due to low resolution seismic data and complex inner structure of A oilfield in South China Sea,it is difficult to predict the faults and fractures.This paper adopted duplex wave migration（DWM） technology to predict the faults and fractures in this oilfield.Based on 3D seismic shot gather information and pre-stack depth migration velocity model in depth domain,combined with DWM velocity scan and migration aperture analysis,DWM technology was used to refine the velocity model further,then obtained the 3D data of fault and fractures imaging.According to the DWM data and its explaining results,depth migration data and its attributions,such as coherence cube,dip and amplitude and so on,structure explaining results by normal seismic explanation,drilling and logging data,the characteristics and distribution law of the faults and fractures of the oilfield were recognized.It is proved that the DWM technology can be used to not only predict the fault and fracture system,which can be predicted by normal seismic,but also predict those unpredictable fault,fracture,and lithologic interface.%南海A油田地层的内部结构复杂、地震资料分辨率低,对其断层和裂缝的预测较为困难。采用近年发展起来的双反射偏移技术,对该油田开展了断层和裂缝预测。双反射偏移技术以精细处理的三维地震炮集资料及叠前深度偏移的深度域速度模型为基础,通过双反射偏移速度扫描和偏移孔径分析,进一步精细化速度模型,实施双反射偏移处理,获得断层和裂缝成像的三维数据体。通过对双反射偏移数据体及其解释结果,以及深度偏移数据体及其沿层相干、倾角、振幅等属性,常规地震构造解释结果和钻井、测井等信息进行联合解释,可了解并获得该油田断层和裂缝的性质及分布规律。双反射偏移技术不仅可以预测与常规地震认识相一致的断裂系统,还可以有效分析根据常规地震资料难以预测的断层、裂缝及岩性的突变界面。