Kirchhoff叠前时间偏移在南阳油田复杂构造成像中的应用

摘要

Kirchhoff叠前时间偏移比常规偏移具有方法简单、运算速度快以及可操作性强,而且可以应用到2-D和3-D地震数据偏移成像.Kirchhoff叠前时间偏移是高频近似条件下的偏移算法,可以利用射线跟踪技术可以获得地震波旅行时间,沿着该射线路径传播的时间积分求和来实现偏移成像.由于射线跟踪算法适应于横向变速介质,因此,Kirchhoff叠前时间偏移也适应横向变速介质.我们将该方法应用于南阳油田复杂构造的成像,该区构造产状不仅陡,断层也多,偏移结果表明Kirchhoff叠前时间偏移在该区可以获得较好的地震成像效果.%A method of pre-stack time migration is presented, which is simpler, faster, and more flexible than the conventional method which is based on the principles of pre-stack Kirchhoff time migration and can be applied to both 2-D and 3-D data. Based on ray in the space-time(x-t) domain, Kirchhoff pre-stack time migration is a high frequency approximation, and it also uses ray tracing to estimate the travel-time. This travel-time is used by Kirchhoff pre-stack time migration to obtain migration summation trajectories.Since the travel-time is extracted using tracing, the migration can practically handle any lateral velocity variations. We applied this method to the imaging for complex media in the Nanyang oilfield where the structure is steep and faults are also much more. The results show that Kirchhoff pre-stack time migration in ensuring calculated on the basis of efficiency, yields good images of the complex media.