各向异性介质控制束偏移及海上数据应用实例  

A controlled beam migration for anisotropic media and its application to marine data

作　　者：张瑞 黄建平[1,2] 李振春 王炜[3] 袁双齐 庄苏斌 ZHANG Rui;HUANG Jianping;LI Zhenchun;WANG Wei;YUAN Shuangqi;ZHUANG Subin(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China;Laboratory for Marine Mineral Resources,Qingdao Pilot National Laboratory for Marine Science and Technology,Qingdao 266071,China;Department Research Institute,Geophysical Division of China Oilfield Services Limited,Tianjin 300451,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,青岛266580 [2]青岛海洋科学与技术试点国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266071 [3]中海油田服务股份有限公司物探事业部数据处理解释中心,天津300451

出　　处：《海洋地质与第四纪地质》2020年第1期184-197,共14页Marine Geology & Quaternary Geology

基　　金：国家重点研发计划“超深层弱信号增强、速度建模与保幅偏移技术研究”（2016YFC060110501）;国家自然科学基金面上项目“面向深部储层的时空域自适应高斯束成像理论方法及优化”（41874149）;国家科技重大专项“薄互层全波形反演和最小二乘偏移联合成像”（2016ZX05002-005-07HZ），“基于多次散射理论的散射波地震成像技术”（2016ZX05014-001-008HZ）

摘　　要：随着勘探区域逐渐从陆地过渡到海洋,勘探目标逐渐趋于复杂化,高精度成像方法已经成为海洋油气勘探的瓶颈技术。高斯束偏移是一种灵活且高效的深度域偏移方法,对实际资料成像具有较好的适应性。该文发展了一种适应于海洋观测系统的高精度高斯束偏移方法,首先将海上接收的共偏移距地震记录进行加窗局部倾斜叠加,通过数学变换将共炮域公式推广到共偏移距域,再从炮点和检波点分别进行射线追踪,最后采用数据驱动的方式进行成像。一方面,考虑到地下介质的各向异性,引入了各向异性射线追踪方程;另一方面,根据有效信号和干扰信号在τ-p域中的相干性差异,在高斯束偏移过程中对地震信号进行控制,降低偏移剖面中的随机噪声,提高同相轴的连续性,最终实现了一种VTI介质共偏移距域数据驱动控制束偏移理论方法。在实现算法的基础上,通过各向异性洼陷模型、修改的SEG/Hess VTI模型及海上实际资料成像试处理,结果表明:各向异性参数对共偏移距道集中的大偏移距信息成像质量改善明显;当地层各向异性不能忽略时,新方法能够更加准确地恢复地下的复杂构造;新方法能够在一定程度上提高低信噪比数据的偏移成像效果。As exploration areas move from the land to the sea,research targets get more complicated,and the high-precision imaging method becomes critical for marine oil and gas exploration.Gaussian beam migration(GBM)is a robust imaging method with high computational efficiency and flexibility.A high-precision GBM method,suitable for marine observation systems,has been developed by the authors in this paper,which contains the transformation between common-shot and common-offset domains and the data-driven framework.On one hand,considering the anisotropy of the subsurface media,an anisotropic ray tracing equation is introduced.On the other hand,based on the semblance difference between signal and disturbance in theτ-p domain,we develop the semblance threshold filtering method to eliminate disturbance during GBM procedure,thereby reducing migration noise.Numerical tests on anisotropic sag model,modified SEG/Hess VTI model and marine data suggest that(1)anisotropic parameters can improve the imaging quality significantly for the large offset data,(2)the proposed method can more accurately recover the complex structure,and(3)the new method may improve the signal-to-noise ratio(S/N)of the migration profile to a certain extent.

关 键 词：各向异性 高斯束偏移 共偏移距域 数据驱动 控制束偏移 

分 类 号：P738[天文地球—海洋地质]