海洋“犁式”电缆地震资料采集与处理方法

The acquisition and process method of marine plow cable streamer seismic data

海洋宽频勘探技术是解决中深层构造成像问题、提高地震分辨率、实现高精度勘探的重要方法,但受海上地震采集方式的制约,宽频带地震数据比较难以获取,常规拖缆地震资料因受海水表面产生的鬼波影响,存在陷频问题。设计了一种"犁式"电缆采集技术,充分考虑了电缆沉放深度不同的特点,利用不同沉放深度具有不同陷波这一特征获取了宽频信息,达到了宽频采集的目的;提出了一种"犁式"电缆地震资料τ-p域鬼波压制方法,有效压制了鬼波影响,拓展了地震频带宽度,提高了地震资料分辨率。南海深水区实际资料应用效果表明,利用本文技术与方法得到的宽频地震资料在地震分辨率、波阻特征及中深层成像方面明显优于常规地震资料,且低频成分丰富,可以有效剔除鬼波导致的假象,使储层反演结果更加准确可信,这在一定程度上解决了南海深水区宽频地震信息获取的难题,填补了国内海洋深水宽频地震勘探技术的空白。

The broadband marine seismic exploration technology is an important method to solve medium-deep structural imaging, improve seismic resolution and realize high precision exploration. However, due to the constraints of the marine seismic acquisition mode, the broadband seismic data is difficult to be obtained. The traditional streamer seismic acquisition affected by the ghost of free surface causes the problem of frequency trap. In this paper, a plow cable acquisition technology is designed with full consideration of the character of cable with different depths. Using the feature of different frequency traps with different depths, the broadband seismic is obtained, thus achieving the purpose of broadband acquisition. Meanwhile, a τ -p domain ghost suppression method of plow cable seismic data is developed, which effectively suppresses the ghost wave effect, expands the seismic frequency band width, and improves the resolution of seismic data. The application in deep water area of the South China Sea indicates that broadband seismic data obtained by this method is superior to the conventional seismic data in the seismic resolution, wave impedance characteristics and the medium-depth imaging, which can effectively eliminate the illusion caused by the ghost, obtaining more accurate and reliable results of reservoir inversion. This technology solves the problem of broadband seismic data obtaining, and fills a domestic gap in deep water broadband seismic exploration.