鄂尔多斯盆地东缘二叠系下石盒子组沉积体系分析

发布时间：2018-03-14 21:29

本文选题：鄂尔多斯盆地东缘　切入点：下石盒子组　出处：《长江大学》2017年硕士论文　论文类型：学位论文

【摘要】：鄂尔多斯盆地是一个大型的多旋回克拉通叠合盆地,构造上处于中国沉积盆地分布的中带,是我国天然气勘探的重点和最具勘探潜力的盆地之一,亦是“西气东输”的骨干资源基地之一。本论文以沉积学、层序地层学、石油地质学的理论为指导,以鄂尔多斯盆地东部下石盒子组为研究对象,系统开展下石盒子组沉积体系研究,为鄂尔多斯盆地下石盒子组的进一步油气勘探提供重要的基础地质资料。研究区下石盒子组地层下石盒子组自下而上可划分为盒8、盒7、盒6、盒5四个岩性段,以及上部与之整合接触的上石盒子组底部盒4段和下部与之整合接触的山西组顶部地层。根据前人研究成果,以及盆地地层发育特征及其沉积作用特点,在下石盒子组识别出河流三角洲体系和湖泊体系,并结合盆地区域构造背景和沉积演化特征,进一步将研究区的三角洲划分为辫状河三角洲(盒8段)和曲流河三角洲(盒7段)两种类型,并指出该类三角洲具有河控浅水型的特征,即在三角洲平原和前缘以分流河道和水下分流河道砂体为其主要骨架砂体,而于三角洲前缘河口坝、前缘席状砂及远砂坝不太发育。在沉积相分析的基础上,运用高分辨率层序地层学理论,首先进行了层序界面的识别及地层堆积叠加样式的确定,进而对鄂尔多斯盆地东缘下石盒子组进行了高分辨率层序地层学划分,在下石盒子组划分出1个长期旋回、4个中期旋回、10个短期旋回,确定了相应的下石盒子组的地层层序划分方案。并分析了下石盒子组不同级次旋回层序发育特征、类型及成因特征。通过层序地层对比,建立了鄂尔多斯盆地东缘二叠系下二叠统下石盒子组等时层序地层对比格架,分析层序地层格架内沉积体系的发育特征,归纳总结出下石盒子组湖泊-三角洲沉积模式。
[Abstract]:The Ordos Basin is a large polycyclic craton superimposed basin, which is located in the middle zone of sedimentary basins in China, and is one of the most important and potential basins for natural gas exploration in China. This paper is guided by the theories of sedimentology, sequence stratigraphy and petroleum geology, and takes the Lower Shihezi formation in the east of Ordos Basin as the research object. A systematic study of the sedimentary system of the Lower Shihezi formation was carried out. It provides important basic geological data for further oil and gas exploration of the Xiashihezi formation in Ordos Basin. The Lower Shihezi formation of the Lower Shihezi formation in the study area can be divided into four lithologic formations from the bottom to the top. As well as the upper part of the Upper Shihezi formation and the lower part of the Shanxi formation, which are in contact with the upper part of the Upper Shihezi formation and the lower part of the Shanxi formation, according to the previous research results, and the characteristics of the basin strata development and sedimentary processes, In the Lower Shihezi formation, the river delta system and the lake system are identified, and combined with the regional tectonic background and sedimentary evolution characteristics of the basin. The deltas in the study area are further divided into braided river deltas (Bo8 member) and meandering river deltas (Bo7 member), and it is pointed out that these deltas have the characteristics of fluvial shallow water type. That is to say, distributary channel and underwater distributary channel sand body are the main skeleton sand bodies in delta plain and front edge, but they are not very developed in delta front estuary dam, front mat sand bar and far sand bar. Based on the theory of high-resolution sequence stratigraphy, the identification of sequence interface and the determination of stratigraphic stacking superposition style are first carried out, and then the high-resolution sequence stratigraphy division of the Lower Shihezi formation in the eastern margin of Ordos Basin is carried out. In the lower Shihezi formation, there are 1 long cycle, 4 middle cycle and 10 short term cycles. The stratigraphic sequence division scheme of the lower Shihezi formation is determined, and the development characteristics of the different order cycles of the lower Shihezi formation are analyzed. Through sequence stratigraphic correlation, the isochronous sequence stratigraphic correlation framework of Lower Permian Lower Permian in the eastern margin of Ordos Basin is established, and the developmental characteristics of sedimentary system in sequence stratigraphic framework are analyzed. The lacustrine delta sedimentary model of the Lower Shihezi formation is summarized.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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