【作者】 周小进；

【导师】 郭建华；

【作者基本信息】 中南大学 ， 矿产普查与勘探， 2009， 博士

【摘要】 我国南方二叠系蕴含着丰富的海相油气资源,已成为四川盆地重要的油气勘探目的层之一,但与其较大的盆地沉积面积相比,现今油气发现尚微不足道。因此,如何在南方其它地区选择有利石油地质条件区块,扩大油气发现,成为当前面临的主要问题。为此,本论文以系统解剖我国南方二叠系沉积演化特征为主要目的,应用层序地层学、古地理学、石油地质学等理论,按构造控盆、盆地控相的研究思路,从区域构造背景和点上的层序地层学分析出发,依托大量的露头剖面点资料,对整个南方地区的二叠纪进行了构造—层序岩相古地理研究,揭示了在等时层序地层格架下的盆地沉积充填演化和生、储物质的空间分布规律,为今后南方海相油气勘探选区评价提供了地质依据。同时,本文提出的构造—层序岩相古地理研究方法和表达技术,可为同类研究提供借鉴。本论文主要结论与创新点如下:①应用Vail经典层序地层学理论,通过6条基干剖面、22条辅助剖面及部分钻井剖面的层序地层学分析与对比,将我国南方二叠系划分为2个超层序和12个三级层序。研究表明,三级层序类型主要为Ⅱ型,Ⅰ型层序仅分布在二叠系的顶、底和中上二叠统之间。②二叠纪我国南方总体处于拉张背景,发育了由陆缘向陆内延伸发展的裂陷盆地;受东吴运动影响,扬子和华夏克拉通遭形成了两个二级海平面升降沉积旋回;陆缘裂陷盆地是低位期沉积的主要场所,而克拉通区主要为海侵和高位期沉积,低位期主要表现为陆上风化残积、河流沉积或仅发育厚度很薄的沼泽相含煤碎屑岩。③以超层序的体系域为单元,依据200多个资料点,再造了二叠纪六个关键时期构造—岩相古地理的时空展布与原型盆地的沉积充填特征。研究认为,中二叠世属缓慢扩大型沉积,发育具缓坡性质的单一碳酸盐台地体系,晚期仅在东南沿海发育高位三角洲体系;晚二叠世属逐渐退缩型沉积,在湘桂裂陷盆地两侧形成对称分布的陆地—碳酸盐台地或混积台地的沉积体系组合。④构造-层序岩相古地理的空间展布特征表明,二级层序的海侵期和最大海泛期是二叠纪烃源岩发育的主要时期,分别在克拉通的缓坡台地上、裂陷槽盆和古陆周缘形成了碳酸盐岩、泥质岩和煤系三类烃源岩。⑤储集相发育条件表明,中上扬子克拉通是发育层序界面古岩溶、台缘礁滩、白云岩以及河流、三角洲、滨岸相碎屑岩等多种类型的储层区,右江和湘桂裂陷盆地是发育斜坡相碳酸盐岩重力流、盆底浊积扇和孤台碳酸盐岩的储层区,这些储层与烃源岩在空间上可构成上下或侧向接触组合。更多还原

【Abstract】 There is remarkable marine petroleum resource in Permian in south of China which has been one of the most important petroleum exploration target, but the finding of petroleum is still poor compared with its big sedimentary area. How to choose more favorable block and enlarge finding of petroleum in other regions in south of China had been the main problem. So this paper regards systems analysis of the depositional evolvement as a goal of Periman in south of China, applying theories of sequence statigraphy, paleogeography and geology of petroleum, The tectonic-sequence-based lithofacies and paleogeography of Permian in south of China are studied based on lots of outcrop section data and analysis of regional tectonic background and sequence statigraphy by ways of tectonic controlling basin and basin controlling lithofaciese. Through above study, the basin deposition filling evolution and the distribution laws of source and reservoir rock under isotime sequence statigraphy trellis are revealed in Permian which provided geology basis for later exploration of marine oil-gas in south of China. At the same time the research methods and expressing skills of tectonic- sequence-based lithofacies and paleogeography are proposed in this paper, and could be used for reference of the same type research.The main conclusions and innovations are as follows:①Two super sequences and twelve third order sequences are divided in Permian in south of China through analysis and contrast of six backbone sections and twenty-two adjective sections and parts of well-sections by the way of classical sequence statigraphy theories proposed by Vail. Third order sequences mainly belong to type II, but type I sequences mainly developed in the top and bottom of Permian and between Middle Permian and Upper Permian.②Pulling setting presents in southern China in Permian forming rift basins, which extends and develops from the edge to the inside of continent. Under the influence of Dongwu movement, two second order cycles forming by up and down of sea level happened in Yangtze and Huaxia craton. Rift basins in continental margin are primary sedimentary location of LST. But craton areas are the main deposition area of TST and HST. Weathering on land and river sediment or only thin coaly clasolite of marsh facies present mainly in LST deposition.③Regarding the sytem territory of super sequence as a unit, and depending on more than two handred data points, the space-time distribution of lithofacies and paleogeography in six key periods of Permian and the filling characters of prototype basins are reveal. Deposition period of Middle Permian belongs to deposition type of slow expanding, and single carbonate platform system with gentle slope presents in Middle Permian. Delta systems of HST only develop in late period of Permian in southeast shore areas. Deposition type of Late Permian belongs to gradual shrinking deposition, in which sedimentary systems of land- carbonate or mixed platform are formed on two sides of Xianggui rift basin.④According to the space distribution characters of tectonic-sequence-based lithofacies and paleogeography, it is showed that three types of hydrocarbon source-rock including carbonate rock, clay and coal in Permian mainly are developed in transgression and maximal sea flooding of two order sequences, and they deposite respectively on platforms with gentle slope in craton, in rift basins and around old lands.⑤According to the conditions of reservoir facies, it is showed that many kinds of reservoirs such as carst develop on sequence boundary. Reef-flat at the edge of platforms, dolostone and clastic of river, delta and littoral facies develop at the middle and up of Yangtze craton, and reservoirs such as carbonate gravity fluid in slope, turbitite fan in basin bottom and carbonate on isolated platforms develop in Youjiang and Xianggui rift basins. These reservoirs may form upside and underside of source rock, or lateral contact with source rock in space.更多还原