用加权偏振滤波压制OBN纵波分量中的地震噪声  

OBN P-wave noise suppression using weighted polarization filtering

作　　者：张庆淮 王明星 路交通 ZHANG Qinghuai;WANG Mingxing;LU Jiaotong(Sinopec Geophysical Corporation,Beijing 100020,China)

机构地区：[1]中石化石油工程地球物理有限公司,北京100020

出　　处：《石油物探》2023年第3期462-470,共9页Geophysical Prospecting For Petroleum

基　　金：中石化地球物理公司基础性技术攻关课题(SGC202207)资助。

摘　　要：舒尔特波和导波是海洋地震勘探中常见的噪声,尤其在浅海地区,能量很强的舒尔特波和导波往往掩盖了地震信号,极大地降低了地震数据的信噪比。利用浅海OBN采集中的水检和陆检垂直分量数据,对信号和噪声进行加权偏振分析,并利用它们的不同偏振参数设计滤波器,在一定的频率内利用加权偏振滤波压制舒尔特波,在一定的速度范围内利用加权偏振滤波压制导波,从而取得很好的噪声压制效果。加权偏振滤波解决了OBN数据中的噪声在水检和陆检两个分量中的能量差异造成的噪声识别困难,而且基于同一物理点的地震道计算,并对每个接收点的多分量数据独立处理,不受空间假频的影响,相比基于FK或Tau-p变换的方法具有明显优势。模拟记录试算和实际数据处理结果表明,加权偏振滤波不依赖数据采样密度,可以有效分离OBN数据纵波分量中的舒尔特波和导波,并在压制噪声的同时很好地保护有效信号。A Scholte wave is an interface wave that propagates between a fluid and an elastic solid medium.Its amplitude is greatest at the interface and decreases exponentially away from it in both fluid and solid media.In marine environments,guided waves are generated as a result of the constructive interface created by plane waves undergoing multiple reflections between the free surface and the water bottom at angles of incidence greater than the critical angle.In OBN seismic data,these waves constitute prominent dispersive noise arrivals that contaminate the reflection arrivals.Scholte waves and guided waves with strong energy significantly reduce the signal-to-noise ratio of marine seismic data,particularly in shallow water areas.Many studies have designed and used polarization filtering on multi-component data from the same receiver type(i.e.,multi-component geophone recordings).This study proposed a novel method for suppressing Scholte waves and guided waves in a shallow-water OBN seismic survey using weighted polarization filtering.In our algorithm,the weighted coefficients are first estimated from the original dual-sensor data of the P wave,hydrophone,and geophone VZ data,and polarization analysis is then conducted using the weighted dual-sensor data.The polarization coefficients used for signal-to-noise separation are obtained through weighted polarization analysis.Subsequently,a polarization filter is designed using these polarization coefficients.Finally,the filters are used in data processing within a predefined frequency or velocity range.After filtering,the seismic data after removing Schulte and guided waves can be obtained.Weighted polarization filtering overcomes the difficulty of noise identification caused by noise amplitude differences between the two vertical components of the OBN data.It operates on seismic traces from the same physical point and is unaffected by spatial aliasing.This is an advantage over methods based on FK or Tau-p transforms,and it has achieved good results when processing syntheti

关 键 词：加权偏振滤波 OBN 舒尔特波 导波 纵波 噪声压制 双检数据 

分 类 号：P631[天文地球—地质矿产勘探]