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东濮凹陷沙三下古地理背景及沉积相展布研究
Paleogeographic Background and Sedimentary Facies Study on the Lower of the Third Member of the Shahejie Formation of Paleogene in Dongpu Sag
【作者】 付菊;
【导师】 于兴河;
【作者基本信息】 中国地质大学(北京) , 矿产普查与勘探, 2008, 硕士
【摘要】 东濮凹陷是我国东部渤海湾盆地一个典型的富油气盐湖盆地。长期以来对东濮凹陷隐蔽油气藏尤其是岩性油气藏的主要类型、分布规律及其勘探方法未能有一个较清晰的认识和比较完善的勘探思路与方法,所以了解研究区内沉积相类型、平面展布及其与油层的配置关系,进一步认识砂体类型及其时空分布规律,对东濮凹陷的进一步勘探与开发有着重要的意义。通过对研究目的层段22口钻井岩心的观察与描述,识别出9种原生构造、4种变形构造、黄铁矿特殊矿物和鱼化石等,划分出四大类(砾岩、砂岩、粉砂岩及泥岩)岩相。在岩心观察的基础上,结合测井及录井资料归纳出9种测井相及其组合。依据高分辨率层序地层学原理,综合考虑受构造运动、沉积物供应、湖平面变化和气候影响的基准面旋回和沉积物的体积分配,对研究目的层段进行了高分辨率层序地层的划分,在研究目的层段共识别出一个长期旋回与和两个中期旋回。在收集众多前人研究资料基础上,通过对东濮凹陷古近系沙三段下亚段钻井岩心和大量测井资料的观察、分析与研究,提取出岩石学特征、沉积构造、电测曲线、剖面结构及粒度特征等沉积相标志,从东濮凹陷古近系沙三段下亚段中划分出辫状河三角洲、扇三角洲、正常三角洲及湖泊四个沉积体系,详细描述和综合归纳了各沉积体系及沉积亚相的特征,并进一步得出了研究目的层段主要为湖泊-三角洲沉积,最后归纳总结出相应的沉积模式。在东濮凹陷构造-沉积演化及沉积体系展布特征研究的基础上,结合重矿物组合特征、稀土微量元素特征及砂岩百分含量的平面展布特征,对研究区古近系沙三段下亚段的物源进行了探讨。认为研究区主要有四个物源区,分别位于盆地的西部、东部、北部及东南部。在前人研究的基础上,结合沉积体系及物源的研究,对研究目的层段进行了古地理编图,探讨了该区沉积体系和砂体的时空演化特征,最后初步指出了研究区的的有利储集相带。
【Abstract】 Dongpu sag is a typical salt lacustrine sub-basin with prolific oil and gas in Bohaiwan basin in east China. For a long time, main type of subtle reservoir, especially the lithologic, distribution law and exploration method are not recognized clearly. Therefore, investigating the sedimentary facies, the spreading characteristic of facies zone and the relations of them to the oil layer disposition, the sandstone body type and the space-time distribution rule are very important to the oil field of Dongpu sag for further exploration and the development.According to observing and describing core of 22 wells in the region, 9 kinds of original structure, 4 kinds of deformational structure, pyrite and fish fossil are identified, and 4 major kinds (gravel stone, sandstone, siltstone and mudstone) lithofacies are divided. On the base of core observation, combining well logging and logging, 9 sorts of log facies and the association are divided.Based on the principle of high resolution sequence stratigraphy, as well taken into account synthetically base level cycle and volumetric partitioning and facies differentiation controlled by tectonics movement and sediment supply and sea-level change and climate, high resolution sequence stratigraphy division was applied in the lower of the third member of the Shahejie Formation. The lower of the third member of the Shahejie Formation can be divided into 1 long-term cycle and 2 mid-term cycles.On the basis of lots of forerunners’ data and research in this thesis, combining drilling data with observation and analysis of well core, The lower of the third member of the Shahejie Formation can be divided into four kind of sedimentary systems such as braided delta, fan delta, delta and lake by using sedimentary facies signs which is rock feature, sedimentary structure, well log and section texture, each of the sedimentary systems and subfacies are described and generalized in detail. At last, I concluded that the lower of the third member of the Shahejie Formation mainly developed shallow lake and delta sedimentary systems of Dongpu sag. On the basis of the analysis above, I deduce one sedimentary models of the Dongpu sag in the lower of the third member of the Shahejie Formation in Paleogene.On basis of structure-sedimentation evolution and distribution of sedimentary facies in Dongpu sag, combined with the characteristics of heavy minerals combination, characteristics of rare earth element and trace element, the planimetric distribution of sandstone and lith-facies, the lower of the third member of the Shahejie Formation’s palaeogeographical pattern are analysed, and four resource areas are divided, which located at the Western, East, North and Southeast of the basin.According to the forerunners’ data, combining the investigation of sedmentary system and the source of the sandstone bodies, lithofacies-paleogeography map working out. In the end, I expound the plane-topology rule of sedimentary facies in the different period and the planimetric distribution of the good reservoir sandstone, and point out the favorable accumulation area belt.
【Key words】 Dongpu sag; Paleogene; analysis of provenance; sedimentary facies; paleogeograph;
- 【网络出版投稿人】 中国地质大学(北京) 【网络出版年期】2008年 08期
- 【分类号】P618.13
- 【被引频次】2
- 【下载频次】456