断陷湖盆沉积层序演化模式及主控因素分析
The Evolution Model of Depositional Sequences of Rift Lacustrine Basin and Analysis on its Main Controlling Factors
赵春晨 1刘豪 2张帅 3潘卫红 3马波2
作者信息
- 1. 陕西延长石油(集团)有限责任公司研究院,西安710075
- 2. 中国地质大学(北京)海洋学院,北京100083
- 3. 中国地质调查局油气资源调查中心,北京100029
- 折叠
摘要
渤海湾盆地是我国东部新生代发育的主要含油气断陷湖盆,具有十分可观的资源储量.为了更好地指导油气储层预测,辅助勘探方案的制订,通过黄河口地区丰富的高分辨率地震数据以及钻测井等资料,全面分析了渤海湾盆地黄河口西洼东营组沉积层序的时空演化规律及其主控因素间的作用关系,最终得出如下结论:研究区东营组可划分为3套三级层序,其中SQ3和SQ2进一步划分为湖扩域和高位域.层序内部主要发育扇三角洲、辫状河三角洲、曲流河三角洲和湖相四种沉积体系,从SQ3至SQ1呈明显的继承性发育特征.沉积层序演化过程主要受到了古地貌和基准面变化的控制,其中坡折带作为古地貌的重要表现,它的形态和规模成为控制层序和沉积体系的首要因素;其不仅为沉积物供给提供保障,而且成为沉积物的搬运和卸载有利场所;另一重要影响因素是基准面变化,它通过影响A/S的大小,控制沉积物的储存状态,形成不同类型的沉积组合,最终在两种因素的耦合下形成了黄河口西洼复杂的层序、沉积模式.北部陡坡带,层序地层以断失现象出现,主要发育曲流河三角洲沉积体系.中部砂质潍坝大面积发育,而在南部斜坡带不整合特征以地层超覆为主,并形成持续发育、规模较大的辫状河三角洲沉积体系.未来勘探目标可设定为分布在滨浅湖砂质滩坝中的有利储集砂体.
Abstract
Bohai Bay basin is a main petroliferous rift basin in eastern China,which is developed in Cenozoic and possesses giant reserves.For guiding oil-gas reservoir prediction and assisting establishment of exploration plan,using abundant seismic data,well logs,et al.,thoroughly analyze the time and space evolution rules of depositional sequence of Donying Formation in western Huanghekou sag of Bohai Bay basin and their main controlling factors' interplay.Finally the following conclusions was got:Dongying Formation in research area will be divided into three 3rd sequences.Among these sequences,SQ3 and SQ2 can be further divided into EST and HST.In these sequences,the depositional systems mainly include fan delta,braided river delta,meandering river delta and the lacustrine depositional system,which show obvious character of successional development from SQ3 to SQ1.The evolution process of depositional sequence has been controlled by palaeogeomorphology and base-level change.And slope break as the important expression of palaeogeomorphology becomes the principal factor of which the shape and scale control the development of the sequences and depositional systems.Slope break don't just guarantee for sediment supply,but it also becomes the place where the deposits transport and unload.On the other hand,via affecting the A/S,base-level changes control the depositional states and form various deposit combination.Finally the balance between slope break and base-level change forms the composite model of sequence and depositional systems in western Huanghekou sag:the sequence stratigraphy of northern steep slope almost appears with ruptured deletion in western Huanghekou sag,and multiple meandering river delta systems exist.In the middle of the sag,the large areas of beach bars can be found.And the unconformable character of the sequence stratigraphy in southern gentle slope displays with the strata overlap and the depositional system is continuously developed with the large-scale braided river delta.The favorable sandy reservoir in beach bar of shore & shallow lacustrine depositional system can be set as the future exploration target.
关键词
沉积层序/演化模式/坡折带/基准面变化/断陷湖盆/东营组/黄河口西洼Key words
depositional sequence evolution/evolution model/slope break/base-level change/rift lacustrine basin/dongying formation/western huanghekou sag引用本文复制引用
基金项目
国家科技重大专项(2011ZX05023-002-005)
出版年
2017
NETL
NSTL
维普
万方数据