宽频地震处理在中深层成像中的应用

Application of Broadband Seismic Processing in Medium and Deep Layer Imaging

受到崎岖海底和复杂地质构造影响,中深层信噪比低、中低频信号弱,基于常规处理地震数据建立的成像速度模型精度不高,成像不清楚,地质特征不明显。中深层成像无法更准确地还原地下真实构造形态,制约了后续潜力圈闭的落实和评价。针对这一问题,采用宽频高精度速度建模技术思路:宽频处理拓宽地震频带,提高速度分辨率,地质约束全局寻优高分辨网格层析成像建模建立精细速度场,进一步改善中深层成像质量。宽频处理技术的发展从根本上挖潜了更多的地震信息,不仅可以具有较高的数据分辨能力,同时拓宽了数据频带。海外某工区实际地震资料的应用结果表明,该方法的采用获得了更精细的速度场,偏移成像质量提高,为靶区中深层成像研究提供了更可靠的依据。

Affected by rugged seabed and complex geological structure,there are low signal-to-noise ratio(SNR),weak mid-low frequency(LF)signal in the middle and deep layers.And the imaging velocity model based on conventional seismic data processing has low accuracy,unclear imaging and inapparent geological characteristics.Therefore the middle and deep layer imaging can not restore the real underground structure accurately,which restricts the implementation and evaluation of potential traps.In order to solve this problem,this paper adopts the broadband high-precision velocity modeling technology:broadband processing is used to broaden the seismic frequency band,enhancing improve the velocity resolution,and high resolution grid tomography modeling with global optimization under geological constraints is used to establish fine velocity field,further improving the imaging quality of middle and deep layers.The development of broadband processing technology has obtained more seismic information fundamentally,which not only has high data resolution,but also widens the data frequency band.The application results of seismic data in a certain overseas area show that,this method can obtain a finer velocity field,and improve the quality of migration imaging,which provides a more reliable basis for the study of middle and deep imaging in the target area.