基于变水速模型驱动的深水水层多次波压制技术研究与应用

摘要

深水地震资料处理中,水层多次波因深水水层为变速体的特性,无法应用浅水水层多次波压制技术(Shallow Water Multi-ple Attenuation,SWMA)进行压制,而传统的自由界面多次波压制技术(Surface-Related Multiple Elimination,SRME)压制水层多次波则不具有针对性.为此,开展了基于变水速模型驱动的深水水层多次波压制技术(Deepwater Water-layer Multiple Elimi-nation,DWME)研究.该技术通过构建海底和变水速模型计算出水层多次波准确旅行时,在τ-p域根据水层多次波旅行时将地震数据进行延拓,得到水层多次波模型,然后应用自适应匹配相减方法完成水层多次波压制.理论模型验证及海外某工区实际地震资料应用结果表明,DWME对深水水层多次波压制效果较好,且针对性强.%It is difficult to attenuate deepwater water-layer multiple using the shallow water multiple attenuation (SWMA)method or the conventional surface-related multiple elimination (SRME)method,because the deepwater water-layer velocity is not con-stant.This paper proposes a deepwater water-layer multiple elimination (DWME)method driven by a variable water velocity mod-el.The method first estimates the water-layer multiple travel-time by building the sea bottom model and variable water velocity model.Then,seismic data wave field extrapolation is performed according to the estimated travel-time in theτ-p domain to predict water-layer multiple.Finally,the adaptive matching subtraction is applied to eliminate the multiples.Testing results on both syn-thetic data and field data show that the DWME can effectively suppress deepwater water-layer multiples.