基于曲波域自适应导向滤波的海上采集脚印压制方法

海上拖缆非观测系统因素造成的采集脚印有时较为严重,给构造解释和储层预测带来较大影响。在叠后提出基于曲波域的自适应导向滤波方法,利用曲波变换特殊的基函数和各向异性分解的优势,最优稀疏表征复杂的地震纹理和采集脚印时空内的“奇异性”,再根据采集脚印在曲波域的分布特点设计自适应滤波器,此滤波器以地震优势方向为导向压制采集脚印的多维曲波系数。模型实验结果表明,海上采集脚印在高维的曲波域系数分散且相对能量较小,能与主要地震反射信息进行区分,当构造复杂时基于曲波域的自适应导向滤波方法能较好压制此类采集脚印,同时不破坏其它地震纹理。实际资料应用结果表明,该方法能较大幅度减弱方差数据体上采集脚印造成的异常相干和断层“毛刺”现象,有效规避将采集脚印解释为“垂直断层”的风险,同时改善浅层的地震波组关系,影响部分砂体连通性的认识。

An acquisition footprint resulting from factors not related to the observation system is sometimes a serious issue in marine streamers,which can have a significant impact on structural interpretation and reservoir prediction.In this work,an adaptive guidance filter in the curvelet domain is proposed for post-stack seismic data.First,by exploiting special basis functions based on a curvelet transformation and anisotropic decomposition,the complex seismic textures and singularities exhibited by acquisition footprints with sparse spatial-temporal characteristics are optimally represented.An adaptive filter is then designed according to the spatial characteristics of the acquisition footprint in the curvelet domain.Finally,the multidimensional curvelet coefficients are mapped by the acquisition footprint oriented with the dominant seismic directions.A simple seismic model test showed that the coefficients corresponding to the marine acquisition footprint in the high-dimension curvelet domain were scattered and carried relatively low energy,which can be distinguished from the main seismic reflection information.If the structure of the seismic model is complex,the proposed method can effectively suppress the acquisition footprint without destroying other textures of the seismic data.An application to actual data indicates that the proposed method can significantly reduce abnormal coherence issues and fault glitches on the variance volume produced by the acquisition footprint.Simultaneously,it effectively avoids the risk of interpreting the acquisition footprint as vertical faults,improves the relationship of seismic wave groups in shallow layers,and enhances the understanding of the connectivity of sand bodies.