神狐海域细粒沉积物水合物储层的地球物理特征研究  

Geophysical characterization of gas hydrate reservoir in fine-grained sediment in Shenhu area

作　　者：姬梦飞 王吉亮 王伟巍[3] 张杰城 刘雪芹 吴时国 JI Mengfei;WANG Jiliang;WANG Weiwei;ZHANG Jiecheng;LIU Xueqin;WU Shiguo(Institute of Deep-sea Science and Engineering,Chinese Academy of Sciences,Sanya 572000,China;University of Chinese Academy of Sciences,Beijing 100049,China;Guangzhou Marine Geology Survey,Guangzhou 511458,China;China University of Petroleum(Beijing),Beijing 102249,China;Harbin Engineering University,Harbin 150001,China;Qingdao Innovation and Development Center of Harbin Engineering University,Qingdao 266000,China)

机构地区：[1]中国科学院深海科学与工程研究所,海南三亚572000 [2]中国科学院大学,北京100049 [3]广州海洋地质调查局,广东广州511458 [4]中国石油大学(北京),北京102249 [5]哈尔滨工程大学,黑龙江哈尔滨150001 [6]青岛哈尔滨工程大学创新发展中心,山东青岛266000

出　　处：《地学前缘》2025年第2期126-139,共14页Earth Science Frontiers

基　　金：国家重点研发计划项目(2022YFC28064001);海南省自然科学基金高层次人才项目(422RC747);国家自然科学基金项目(42106070)。

摘　　要：南海北部神狐海域水合物储层以粉砂质细粒沉积物为主,其饱和度达30%,远高于其他许多地区的细粒水合物储层饱和度。研究该区内细粒沉积物水合物储层特征对于认识水合物富集规律、资源评价和水合物试采开发方案设计均具有重要意义。本研究通过对神狐海域叠前地震数据进行精细处理获得地层速度模型以及角道集数据,进而开展叠前地震反演,获得包括纵横波阻抗、纵横波速度比和泊松比等多弹性参数剖面,结合测井数据对水合物和游离气分布进行精细地球物理描述。通过研究发现:(1)研究区内BSR反射振幅随入射角增大而减弱,BSR在小角度叠加剖面上更易识别;(2)BSR之下发育具有低速异常特征的烟囱构造,可能是深部游离气的向上运移通道;(3)研究区内水合物储层具有较强的横向非均质性,较高饱和度水合物下部一般赋存游离气,表明水合物再循环可能在细粒沉积中的水合物富集起到重要作用。The gas hydrate reservoir in the Shenhu area of the northern South China Sea is primarily composed of fine-grained sediments with a saturation as high as 30%,which is significantly higher than other reservoirs worldwide.Studying the characteristics of fine-grained reservoirs in this area is crucial for understanding the mechanism of hydrate accumulation,resource evaluation,and the design of hydrate trial production and development strategies.In this study,we conducted detailed processing of multi-channel seismic data in the Shenhu area to obtain velocity models and stacked profiles with different offsets.Subsequently,pre-stack seismic inversion was performed to derive high-resolution elastic parameters,including P-wave and S-wave impedance,P-wave to S-wave velocity ratio,and Poisson's ratio.These results were combined with well-logging data to provide a refined geophysical description of gas hydrates and free gas in the fine-grained sediment.Our study reveals the following:(1)The amplitude of the BSR(bottom-simulating reflector)decreases as the incident angle increases,making it easier to identify the BSR on near-offset stacked profiles;(2)Chimney structures with low-velocity anomalies develop below the BSR and may serve as pathways for vertical fluid migration;(3)Hydrate reservoirs in the study area exhibit strong horizontal heterogeneity,and free gas is generally present beneath the hydrate with high saturation,suggesting that hydrate recycling may play an important role in hydrate enrichment in fine-grained sediments.

关 键 词：天然气水合物 地震成像 叠前地震反演 储层刻画 

分 类 号：P618[天文地球—矿床学]