古地理学报2024，Vol.26Issue(4)：941-961,21.DOI:10.7605/gdlxb.2024.04.083
中国断陷和坳陷湖盆高可容纳空间层序细粒重力流沉积及其页岩油意义
Fine-grained gravity flow deposits and their significance for shale oil within high-accommodation sequences in faulted and down-warped lacustrine basins of China
摘要
Abstract
Gravity flows,including coarse-grained and fine-grained gravity flows,are the most im-portant sedimentation processes in deep-lake environments.Fine-grained gravity flow sediments hold signif-icant potential as unconventional shale oil"sweet spot intervals".The distribution characteristics of fine-grained gravity flow sediments within sequence stratigraphic frameworks in lacustrine basins are of great significance to the prediction of shale oil"sweet spot intervals".Through systematic comparative study of gravity flow deposits and sequence frameworks in major lacustrine basins in China,it is found that gravity flow sedimentary systems are mainly deposited in high accommodation sequences.In the lowstand systems tracts(LST)of the faulted/rifted lacustrine basins,coarse-grained gravity flow deposits are developed at proximal sublauctrine fans and thin fine-grained gravity flow sediments are deposited at distal sublaucus-trine fans.The distribution of sublacustine fans is controlled by valley and syn-sedimentary structural slope breaks.Fine-grained channel-levee-lobe systems are developed in transgressive systems tracts(TST).Un-confined-channel sublacustrine fans are developed in highstand systems tracts(HST),and fine gravity flow deposits are distributed in distal sublacustrine fans.Large fine-grained channel-levee-lobe systems in-fluenced by flooding occurred in transgressive systems tracts(TST)of down-warped lacustrine basins.On the steeper slope of syn-depositional flexural breaks,fine-grain sublacustrine fan systems are present.Both fine-grained sublacustrine fan systems and fine-grained channel-levee-lobe systems can be deposited in highstand systems tracts(HST)and lowstand systems tracts(LST).Fine-grained gravity flow deposits at distal sublacustrine fans and channel-levee-lobe systems can form"sweet spot intervals"of shale oil.Mud-flow deposits form"sweet spot intervals"of foliation type,fine-grained debris flow,fine-grained turbidity current,fine-grained hyperpycnal flow and fine-grained transition flow deposits form"sweet spot intervals"of lamination type and bedding type,while fine-grained concentrated density flow deposits only form"sweet spot intervals"of bedding type.Fine-grained gravity flow deposits are favorable"sweet spot inter-vals"for shale oil exploration and development.关键词
高可容纳空间层序/细粒重力流沉积/陆相盆地/页岩油/"甜点段"Key words
high-accommodation sequence/fine-grained gravity flow deposits/continental basin/shale oil/"sweet spot interval"分类
天文与地球科学引用本文复制引用
冯有良,邹才能,杨智,蒋文琦,张天舒,张洪,刘畅,王小妮..中国断陷和坳陷湖盆高可容纳空间层序细粒重力流沉积及其页岩油意义[J].古地理学报,2024,26(4):941-961,21.基金项目
中国石油天然气股份有限公司科技部项目(编号:2021DJ18,2021DJ1802)资助.[Financially supported by PetroChina Science and Technology Projects(Nos.2021DJ18,2021DJ1802)] （编号:2021DJ18,2021DJ1802）
