南海深反射地震关键处理技术研究及应用

Research and application of deep reflection seismic processing technology in South China Sea

南海深海盆区海底和基底崎岖、地下地质构造复杂,这些因素使得地震资料发育大量的复杂多次波和绕射波,同时,受鬼波影响,深反射地震剖面低频信号损失严重,这给中深层目标成像带来了巨大挑战。针对南海二维深反射地震资料深层低频信息能量弱、复杂多次波发育、复杂绕射波干扰严重问题,采用自适应鬼波去除、组合法复杂多次波压制、多属性联合复杂绕射波衰减3项关键技术进行攻关处理,最终实际资料处理结果表明,深部弱反射信号低频成分5~13 Hz能量得到明显增强,深部地层信噪比从5提高到10,疑似莫霍面成像改善明显,为后续综合地质研究奠定了坚实基础。

The seabed and base of the deep-sea basin area of the South China Sea are rugged and have complex underground geological structures.These factors make a large number of complex multiplewaves and diffraction waves of seismic data develop.Meanwhile,caused by ghost waves,the lowfrequency signal loss of deep reflection seismic profile is severe,which brings great challenges to the imaging of middle and deep targets.Concerning the problems of weak energy of deep low-frequency signal,the development of complex multiples and serious interference of diffraction waves in the 2D seismic data of the South China Sea,three key processing techniques,namely adaptive ghost wave removal,complex multiple wave combination suppression method and multi-attribute constrained complex diffraction attenuation,are adopted.The actual seismic data processing results show that:the deep 5-13 Hz low-frequency signal energy has been significantly enhanced,the signal-to-noise ratio has been increased from 5 to 10,and the suspected Moho imaging has improved significantly,which provides reliable basic data for subsequent comprehensive geological research.