基于逆时偏移的浅水自由表面多次波成像技术  

Free surface multiple imaging technology of shallow water based on reverse time migration

作　　者：刘斌 LIU Bin(Sinopec Geophysical R&D Center,Nanjing 211110,China)

机构地区：[1]中石化地球物理公司科技研发中心,南京211110

出　　处：《海洋地质前沿》2023年第5期83-92,共10页Marine Geology Frontiers

基　　金：中石化项目“单点高密度地震采集技术研究”(JP18024-1)。

摘　　要：浅水环境中,多次波广泛发育且很难压制。与一次有效波相比,多次波具有反射角小、传播路径长、照明范围广等优点,如何较好地处理浅水自由表面多次波是海洋地震资料处理的重要环节。本文改变将多次波当作噪音进行压制的做法,实现对其有效利用。首先基于确定性水层多次波压制(DWD)技术加自由表面多次波压制(SRME)技术联合实现对于浅水自由表面多次波与有效反射波的良好分离;然后利用分离的有效波通过反馈环理论实现不同阶次多次波的预测;最后基于成像精度更高的逆时偏移成像技术,实现不同阶次多次波的分阶成像。模型资料和实际资料的试处理结果表明,组合分离方法实现了对浅水自由表面多次波与反射波的良好分离,而分阶成像既避免了成像过程中串扰噪音的影响,又通过利用不同阶次多次波进行成像,扩大了成像照明范围,提升了浅水发育区域地震资料的成像质量,实现了对浅水自由表面多次波的有效利用。In shallow water environment,multiples are widely developed but difficult to suppress.How to deal with the shallow free surface multiples is an important part of marine seismic data processing.Compared with the primary effective wave,the multiples have advantages of small reflection angle,wide illumination range,long propagation path,and high resolution.We improved the traditional suppression practice in which multiples are treated as noise.First,based on the deterministic water layer multiple suppression(DWD)technology and free surface multiple suppression(SRME)technology,shallow water free surface multiples and effective reflected waves could be well separated.Secondly,multiple waves of different orders could be predicted using separated effective waves in the feedback loop theory.Finally,based on the reverse time migration imaging technology with higher imaging accuracy,the imaging of multiples of different orders could be achieved.Our trial processing results of model data and actual data show that the combined separation method could well separate multiples from reflected waves at shallow water free surface.The fractional imaging not only avoided the influence of crosstalk noise in the imaging process,but also expanded the imaging illumination range and improved the imaging quality of seismic data in shallow water areas.Therefore,the effective use of shallow-water free surface multiples is realized.

关 键 词：浅水区域 自由表面多次波 DWD技术 SRME技术 多次波逆时成像 

分 类 号：P631[天文地球—地质矿产勘探]