海洋地质与第四纪地质2025，Vol.45Issue(6)：141-150,10.DOI:10.16562/j.cnki.0256-1492.2025111301
琼东南盆地冷泉区天然气水合物储层的年代与沉积环境:源自钻孔沉积物的记录
The age and sedimentary environment of gas hydrate reservoirs in the Qiongdongnan Basin of South China Sea:Evidence from borehole sediment
摘要
Abstract
The Qiongdongnan Basin constitutes a significant gas hydrate accumulation zone in the northern South China Sea.The environment and age of its hydrate reservoirs is crucial for understanding the formation and guiding exploration development.We analyzed the foraminiferal and calcareous nannofossil biostratigraphy of sediments from boreholes W07B,W08B,and W09 in the Songnan low uplift from the GMGS5 Expedition,and boreholes W01,W03,and W04 in the Lingnan low uplift from the GMGS6 Expedition.The formation time of the reservoir was precisely determined and the depositional environment investigated.Three foraminiferal biozones and two calcareous nannofossil biozones were identified,revealing the oldest strata as being Middle Pleistocene,approximately 0.75 Ma old.Hydrate reservoirs formed mainly since 440 ka B.P.,exhibiting a high sedimentation rate from 25.67 to 45.44 cm/ka.The environment has been unstable since 440 kaB.P.,with multiple disturbance by shallow-water allochthonous deposits.The hydrade deposits were characterized by the abundant occurrence of benthic foraminifera from nearshore and shallow marine environments,low CaCO3 content,increased terrigenous material,and coarser sediment grain size.The high sedimentary rate of over 20 cm/ka and exogenic transport provided favorable storage space for hydrate formation,particularly for seepage-type hydrate development.Allochthonous deposition was the key controlling factor for hydrate accumulation in the study area.关键词
生物地层年代/沉积速率/异地搬运沉积/天然气水合物储层Key words
biostratigraphy/sedimentary rate/allochthonous deposition/hydrate reservoir分类
海洋科学引用本文复制引用
WU Cong,DUAN Xiao,CHEN Fang,ZHUANG Chang,ZHOU Yang,JIN Meng,LU Yamin,PENG Zhiyuan..琼东南盆地冷泉区天然气水合物储层的年代与沉积环境:源自钻孔沉积物的记录[J].海洋地质与第四纪地质,2025,45(6):141-150,10.基金项目
国家自然科学基金联合基金项目"南海北部冷泉系统演化与天然气水合物动态成藏耦合关系"(U2344222) （U2344222）
