三维地震与OBS联合勘探揭示的神狐海域含水合物地层声波速度特征  

The acoustic velocity characteristics of sediment with gas hydrate revealed by integrated exploration of 3D seismic and OBS data in Shenhu area

作　　者：张光学[1] 徐华宁[1] 刘学伟[2] 张明[1] 伍忠良[1] 梁金强[1] 王宏斌[1] 沙志彬[1] 

机构地区：[1]国土资源部海底矿产资源重点实验室,广州海洋地质调查局,广州510075 [2]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《地球物理学报》2014年第4期1169-1176,共8页Chinese Journal of Geophysics

基　　金：国际科技合作项目(2010DFA21630-2);国家重点基础研究发展计划(973计划)(2009CB219);国家青年科技基金(41206047)联合资助

摘　　要：以三维高分辨地震与海底高频地震仪(OBS)联合勘探数据为基础,获得海底之下沉积层的地震反射成像剖面及多波信息,并以此确定研究区含天然气水合物沉积层的纵、横波速度的变化特征.根据走时反演获得的横波速度与纵波速度对比分析发现,研究区海底之下500m深度范围内的某些沉积层具有较高的纵横波速度,这一纵波速度升高区域与水合物稳定带对应,而纵波速度下降并且横波速度变化较小的区域,可能与游离气的存在相关.游离气的可能存在与基于这一区域2007年钻探测井结果的普遍认识不完全相符.Based on integrated data acquired with 3-D seismic survey and OBS, both the images of subsurface formation and the information of P/S-wave velocities are obtained, which help to make certain the variation of P/S-wave velocity within the gas-hydrate bearing sediments in the study area. Comparison with the results of P/S-wave velocity calculated from travel time inversion indicates that some sediments have relatively high P/S-wave velocity within the depth of 500 m below seafloor. The abrupt rising of P-wave velocity means the presence of gas hydrate and the high velocity interval corresponds to the hydrate stable zone apparently, but the P-wave velocity decreasing as well slight S-wave velocity decreasing is very likely related to the occurrence of free gas. The presumed occurrence of free gas in the area does not agree with the viewpoints deduced from drilling and coring results within limited depth in this area in 2007.

关 键 词：神狐海域 联合勘探 OBS 天然气水合物 声波速度 

分 类 号：P631[天文地球—地质矿产勘探] P736[天文地球—地质学]