牛庄洼陷沙三中亚段三角洲—重力流体系沉积特征与模式  

Sedimentary Characteristics and Depositional Model of Delta and Gravity Flow System of the Middle Member 3 of Shahejie Formation in Niuzhuang Sag

作　　者：周学文 姜在兴[1,2,3] 汤望新 许文茂[1,2,3] 胡晨林 贾超尘[1,2,3] ZHOU XueWen;JIANG ZaiXing;TANG WangXin;XU WenMao;HU ChenLin;JIA ChaoChen(Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism,Ministry of Education,Beijing 100083,China;School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China;Institute of Scientific Research,China University of Geoscience(Beijing),Beijing 100083,China)

机构地区：[1]海相储层演化与油气富集机理教育部重点实验室,北京100083 [2]中国地质大学(北京)能源学院,北京100083 [3]中国地质大学(北京)科学研究院,北京100083

出　　处：《沉积学报》2018年第2期376-389,共14页Acta Sedimentologica Sinica

基　　金：国家科技重大专项(2017ZX05009-002);国家自然科学基金项目(41772090)~~

摘　　要：为了统一东营凹陷重力流的分类方案,进一步完善断陷湖盆三角洲—重力流体系沉积模式,以牛庄洼陷沙三中亚段三角洲—重力流砂体为研究对象,运用地震、测井和岩芯观察等手段,分析层序格架内三角洲—重力流砂体的沉积特征,分布规律和控制因素。结果表明:牛庄洼陷沙三中亚段可划分为一个T-R层序,即发育快速湖侵和湖退两个体系域,并进一步细分为6个准层序组,分别对应6期三角洲砂体;重力流砂体在湖退体系域PS5—PS1准层序组中分布广泛,但在湖侵体系域分布局限,成因上可分为四种类型:滑动,滑塌,碎屑流和浊流。滑动沉积主要呈带状临近三角洲前缘砂体分布。滑塌和碎屑流沉积分布于较远的洼陷斜坡和斜坡角附近。浊流沉积呈席状分布于洼陷最远的深陷部位;高达200 m/万年的三角洲进积速率,沙三段时期明显增强的断层活动速率,顺物源方向发育的构造坡折带,以亚热带植物为主的孢粉组合特征,δ13CPDB和δ18OPDB值的负漂移现象共同揭示:三角洲高速的进积速率,构造坡折带与断裂活动,温暖潮湿的古气候条件,控制着研究区沙三中亚段三角洲—重力流砂体的形成与分布。In order to unify the classification scheme of gravity flow in Dongying depression and further improve the depositional model of delta and gravity flow system in rifted lacustrine basin,this paper selected the delta and gravity flow sand bodies in the Mid-E 2 s 3 of Niuzhuang sag as research object,then used seismic data,well logs and core observation to analyze the sedimentary characteristics,genetic mechanism,distributions and depositional model of deltaic and gravity flow sand bodies within the framework of sequence stratigraphy.The results show that the Mid-E 2 s 3 of Niuzhuang sag can be divided into one T-R sequence,viz one lacustrine transgressive system tract and one regressive system tract.The T-R sequence can be further divided into 6 parasequence sets which correspond to 6 cycles of deltaic sand bodies.The gravity flow sand bodies were widely distributed in regressive system tract,viz parasequence set 5 to parasequence set 1 while the distribution was limited in transgressive system tract.Four types of gravity flow were recognized:slide,slump,debris flow and turbidity current.Slide deposits showed a zonal distribution near delta front sand bodies.Slump and debris flow deposits distributed farther on the slope or near the slope point.Sheet-like turbidites were distributed in the deep part of the sag.Deltaic progradation rate was up to 200 m/10 4 a.During the E 2 s 3 period,the fault activity rate was significantly enhanced.The structural slope break zone developed along the direction of provenance.Sporopollen assemblage was dominated by subtropical plants.The value ofδ13 C PDB andδ18 O PDB showed a pronounced negative excursion.All these phenomena reveal that,the high speed deltaic progradation rate,structural slope break zone and fracture movement,warm and humid paleoclimate condition controlled the generation and distribution of delta and gravity flow sand bodies in the study area during the Mid-E 2 s 3 period.

关 键 词：三角洲-重力流体 牛庄洼陷 滑动沉积 滑塌沉积 碎屑流沉积 浊流沉 控制因素 

分 类 号：P618.13[天文地球—矿床学]