摘要
白云南洼珠海组沉积时期,盆地处于断陷向拗陷转化阶段,陆架坡折形态以及位置发生巨大变化,导致深水沉积的类型和特征具有明显差异。针对这种坡折演化对深水沉积类型的影响开展研究,通过对白云南洼珠海组三维地震剖面进行解译,识别珠海组各层段陆架坡折带,定量分析坡折特征及其演化规律,探讨坡折演化过程与深水沉积的耦合关系。研究结果表明,通过对珠海组沉积时期陆架坡折带定量分析,将其迁移演化类型划分为下降型、平直型、低角度上升型、高角度上升型4类;在井震结合的基础上,根据地震相组合以及沉积体系分布特点,识别出斜坡扇、块状搬运沉积、深水水道体、盆底扇4种主要的深水沉积类型;并发现陆架坡折演化类型与深水沉积类型存在明显的耦合关系:平直型、高角度上升型、低角度上升型和下降型陆架边缘迁移轨迹分别对应斜坡扇、块状搬运沉积、深水水道体和盆底扇的优势发育。此外,珠海组四段至珠海组三段陆架坡折带整体由下降型向低角度上升型转变,深水沉积体系以斜坡扇及深水水道体发育为主;珠海组三段至珠海组一段早期整体由低角度上升型向下降型转变,深水沉积体系以深水水道-盆底扇沉积体系为主;珠海组一段晚期整体由下降型向高角度上升型演化,深水沉积体系几乎不发育。本研究揭示了陆架坡折迁移对深水沉积体系类型和分布的控制作用,对深入理解深水沉积过程和油气勘探具有重要意义。
In the deposition of the Zhuhai Formation in the Southern Subsag of the Baiyun Sag,Pearl River Mouth Basin,South China Sea,the basin was in the transitional stage from a graben to a sag,and the morphology and location of the shelf slope break underwent significant changes,resulting in distinct differences in the types and characteristics of deep-water sedimentation.We investigated the influence of slope break morphology on deepwater sedimentation types.By interpreting the 3D seismic profiles of the Zhuhai Formation,the shelf slope break zones of various intervals were identified.The characteristics and evolutionary patterns of the slope break were quantitatively analyzed,and the coupling between the slope break evolution and deep-water sedimentation was discussed.Results shows that the shelf slope break migration and evolution types were classified into four categories:descending,straight,low-angle ascending,and high-angle ascending.Based on the integration of well and seismic data,and according to the seismic facies assemblages and distribution characteristics of sedimentary systems,four major deep-water sedimentation types were identified:slope fans,mass transport deposits,deep-water channel complexes,and basin floor fans.A distinct coupling relationship was recognized between the slope break evolution type and deep-water sedimentation type:the straight,high-angle ascending,low-angle ascending,and descending migration trajectories of the shelf margin correspond to the preferential development of slope fans,mass transport deposits,deep-water channel complexes,and basin floor fans,respectively.From the fourth member to the third member of the Zhuhai Formation,the overall shelf slope break zone transitioned from a descending type to a low-angle ascending type,and the deep-water sedimentation system was dominated by the development of slope fans and deep-water channel complexes.From the third member to the early stage of the first member of the Zhuhai Formation,the overall trend transitioned from a low-angle ascending type to a descending type,and the deep-water sedimentation system was dominated by the deep-water channel-basin floor fan depositional system.During the late stage of the first member of the Zhuhai Formation,the overall trend evolved from a descending type to a high-angle ascending type,and the deep-water sedimentation system was almost undeveloped.This study revealed the control effect of shelf slope break migration on the types and distribution of deep-water sedimentation systems,which is of great significance for a deeper understanding of deep-water sedimentation processes and hydrocarbon exploration.
作者
张尚锋
范东旭
李宏义
唐武
王雅宁
朱锐
李冉
ZHANG Shangfeng;FAN Dongxu;LI Hongyi;TANG Wu;WANG Yaning;ZHU Rui;LI Ran(School of Earth Sciences,Yangtze University,Wuhan 430100,China;Key Laboratory of Oil and Gas Resources and Exploration Technology of Ministry of Education,Yangtze University,Jingzhou 434023,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)
出处
《海洋地质前沿》
CSCD
北大核心
2024年第7期11-24,共14页
Marine Geology Frontiers
基金
中海石油(中国)有限公司重大科技项目“南海天然气基础地质与勘探战略方向”(2021-KT-YXKY-05)
国家自然科学基金“南海北部宽缓大陆架海平面变化及双坡折带层序地层模型”(41472098)。
关键词
坡折带
深水沉积类型
沉积演化
珠海组
白云南洼
珠江口盆地
shelf break
deep-water sedimentary type
sedimentary evolution
Zhuhai Formation
Southern Subsag of the Baiyun Sag
Pearl River Mouth Basin