摘要
混积滩坝不仅发育于海相沉积盆地,也广泛发育于陆相断陷湖盆,特别是在缓坡带最为发育并与油气富集密切相关.以饶阳凹陷蠡县斜坡为靶区,基于岩心与测井资料,通过岩心与薄片观察、粒度分析、微量元素含量测定等手段确定了研究区沙一下亚段混积滩坝沉积和分布特征,建立了断陷湖盆缓坡混积滩坝的沉积模式.研究表明,可以依据岩性将蠡县斜坡发育的滩坝分为碎屑岩滩坝、碳酸盐岩滩坝和混积滩坝,其中混积滩坝又可以分为成分混积滩坝和层系混积滩坝.混积滩坝岩性以灰质砂岩、砂质鲕粒灰岩、生物碎屑灰岩等为主,其发育与展布受控于古气候、古物源、古地貌、古水体等地质因素,在斜坡不同位置、不同沉积阶段构成了不同类型的滩坝沉积组合.斜坡近岸缓坡带发育层系混积滩坝以及碎屑岩滩坝,远岸缓坡带发育成分混积滩坝,远岸水下低隆带主要发育碳酸盐岩滩坝.
Not only are mixed rocks distributed in marine basins,but they are also distributed in a large number of hanging wall slope areas in rift sags and related to hydrocarbon accumulation closely.Mainly based on the core data and logging data of the Lixian slope,and the sedimentary characteristics and distribution of mixed beach-bars are studied through the core and thin section observation,grain size analysis,log facies analysis.Firstly,seismic data,pollen data,and trace element data were analyzed to restore the depositional environment controlling factors such as paleoclimate,paleo-provenance,paleogeomorphology,and paleowater characteristics in the first member of Shahejie Formation.Then,the sedimentary model of the mixed beach-bars in the lower submember of the first member of Shahejie Formation in Lixian slope was systematically built.The results show that the beach-bar facies developed in the hanging wall slope area of Raoyang sag can be divided into siliciclastic beach-bars,carbonate beach-bars,and mixed beach-bars according to petrologic characteristics.Moreover,mixed beach-bars can be divided into component-mixed beach-bars and stratified-mixed beach-bars.The lithology of mixed beach-bar was mainly of calcareous sandstone,sandy oolitic limestone,and bioclastic limestone.The distribution of mixed beach-bar was controlled by factors such as paleoclimate,paleoprovenance,paleogeomorphology,and paleo-water characteristics.Therefore,different sedimentary patterns developed in different positions and different sedimentary stages on the slope.Stratified-mixed beach-bars and siliciclastic beach-bars were deposited in the near-shore ramp,and component-mixed beach-bars were deposited in the far-shore ramp.Carbonate beach-bars were mainly distributed on the far-shore low uplift.
作者
杜一帆
朱筱敏
叶蕾
高园
Du Yifan;Zhu Xiaomin;Ye Lei;Gao Yuan(College of Geosciences,China University of Petroleum y Beijing 102249,China;Huabei Oilfield Company,PetroChina,Renqiu 062552,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2020年第10期3759-3778,共20页
Earth Science
基金
国家科技重大专项(No.2017ZX05001-002-002)。
关键词
陆相断陷盆地
饶阳凹陷
沙河街组沙一段
混积滩坝
古环境
沉积
continental rift basin
Raoyang sag
first member of Shahejie Formation
mixed beach-bar
paleoenvironment
sedimentation