琼东南盆地天然气水合物储层沉积时间及成因机制  

Sedimentary time and genesis mechanism of natural gas hydrate reservoirs in the Qiongdongnan Basin

作　　者：梁晨 姜涛[1] 匡增桂[2] 胡亦潘 杨承志 任金锋[2] 赖洪飞 LIANG Chen;JIANG Tao;KUANG Zenggui;HU Yipan;YANG Chengzhi;REN Jinfeng;LAI Hongfei(Hubei Key Laboratory of Marine Geological Resources,China University of Geoscience(Wuhan),Wuhan 430074,China;Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou 510075,China)

机构地区：[1]中国地质大学(武汉)海洋科学系,海洋地质资源湖北省重点实验室,湖北武汉430074 [2]中国地质调查局广州海洋地质调查局,广东广州510075

出　　处：《地学前缘》2025年第2期140-152,共13页Earth Science Frontiers

基　　金：国家自然科学基金面上项目(41976073);中国地质大学(武汉)2022—2023年实验室开放基金项目。

摘　　要：近年来的钻探已在南海北部琼东南盆地证实了天然气水合物的存在,水合物形成时间无疑是深刻理解水合物成藏过程和分布的关键。本研究首次通过对含水合物钻孔的释光年代学研究,揭示天然气水合物储层的沉积时间,结合水合物分布的层段,约束了天然气水合物形成时间的下限,并进而分析了水合物储层的沉积速率及影响因素,为南海北部水合物勘查提供了坚实地质支撑。研究结果表明,该地区天然气水合物形成于距今65~90 ka,且天然气水合物储层沉积速率受冰期/间冰期海平面波动的控制。间冰期海平面上升,陆源碎屑输入减少,导致沉积速率降低;冰期海平面下降,陆源物质输入增加,沉积速率加快,是琼东南盆地天然气水合物储层形成的主要时期。Recent drilling in the Qiongdongnan Basin,located in the northern South China Sea,has uncovered gas hydrate deposits.Understanding the timing of gas hydrate formation is crucial for deciphering the processes of hydrate accumulation and distribution.This study,for the first time,determines the deposition age of gas hydrate reservoirs by analyzing the sediment chronology of hydrate drilling cores.The lower limit of hydrate formation age is established by combining these findings with the distribution of hydrate intervals.Subsequently,the deposition rate and its influencing factors are analyzed,providing robust geological insights for gas hydrate exploration in the northern South China Sea.The results indicate that gas hydrate formation in this region occurred between 65 and 90 ka.The deposition rate of gas hydrate reservoirs is influenced by sea-level fluctuations during glacial and interglacial periods.During interglacial periods,rising sea levels reduced terrigenous clastic input,leading to a decrease in sedimentation rates.Conversely,the primary formation period of gas hydrate reservoirs in the Qiongdongnan Basin coincided with sea-level drops,increased terrigenous material input,and accelerated sedimentation rates.

关 键 词：光释光测年 天然气水合物储层 沉积速率 海平面变化 

分 类 号：TE38[石油与天然气工程—油气田开发工程]