地震属性分析在浅层气识别中的应用研究  

Research on Application of Seismic Attribute Analysis in Identification of Subsea Shallow Gas

作　　者：杨肖迪 淳明浩 罗小桥 姚志广 YANG Xiao-di;CHUN Ming-hao;LUO Xiao-qiao;YAO Zhi-guang(CNPC Research limited company of Engineering Technology, Tianjin 300450, China;CNPC Key Laboratory of Marine Engineering, Tianjin 300450, China)

机构地区：[1]中国石油集团工程技术研究有限公司,天津300450 [2]中国石油集团海洋工程重点实验室,天津300450

出　　处：《海岸工程》2022年第1期26-36,共11页Coastal Engineering

基　　金：中国石油天然气集团有限公司科学研究与技术开发项目——海洋油气管道设计施工关键技术研究(2019B-3010)。

摘　　要：海底浅层气在地层中聚集会降低土层强度或形成高压气囊,危害海洋工程建设,查明工区内海底浅层气分布具有重要意义。土体中含有浅层气会改变土体的物理力学性质,对传播过程中的声波具有改造作用。地震属性分析可以利用声波的多种属性参数,从多个维度进行浅层气识别分析。针对研究区域声学地层剖面资料,利用振幅、瞬时相位、瞬时频率和品质因子四方面的属性进行浅层气识别分析,综合杂乱弱反射、同相轴变粗、同相轴下拉、高频缺失、品质因子相对较差等特征,识别出声学地层剖面上的浅层气反射。研究区域内浅层气呈柱状纵向分布,与断层部分重合,终止于海底表层黏土层,可能是由深部沿着断层向上迁移至浅部聚集形成的。The accumulation of subsea shallow gas in the strata can reduce the strength of the sediments and/or form high pressure gas bags,which can endanger the marine engineering constructions.It is,therefore,of great significance to identify the distribution of the subsea shallow gas in the working area.If the sediments contain shallow gas,their physical mechanical properties could be changed and the acoustic waves during the propagation could be transformed.The seismic attribute analysis can use multiple attribute parameters of the acoustic waves and perform the identification and analysis of the shallow gas from multiple dimensions.In view of the acoustic stratigraphic profile data in the study area,four types of seismic attributes,i.e.amplitude,instantaneous phase,instantaneous frequency and quality factor,are used to identify and analyze the shallow gas.Based on the characteristics such as chaotic weak reflections,lineups widening,lineups pulling-down,high frequency missing,relatively poor quality factor,and so on,the reflections of shallow gas are identified in the acoustic stratigraphic profiles.It is found that the subsea shallow gas in the study area shows a column-like longitudinal distribution,is partially overlapped with the faults and ends in the subsea surface clay layer.This gas may possibly be accumulated by migrating along the faults from the deep part to the shallow part.

关 键 词：浅层气 声学地层剖面 地震属性 高频缺失 品质因子 

分 类 号：P315.9[天文地球—地震学]