【作者】 彭海艳；

【导师】 刘家铎； 李勇；

【作者基本信息】 成都理工大学 ， 沉积学， 2010， 博士

【摘要】 黄骅坳陷孔南地区是一个有利的含油气区带,是大港油田的后继勘探开发战场。前人的研究主要将孔南地区孔店期盆地涵盖于黄骅坳陷新生代盆地之中,缺乏对孔南地区孔店期湖盆演化独特性的研究,通过进一步分析,我们认识到研究区孔店期构造旋回的盆地结构特点与现今埋藏结构有很大的差别,盆地的多期叠加及后期盆地对早期结构改造强烈;同时,在孔店期盆地类型、盆地结构、物源体系及湖盆演化过程等方面也存在着很大的分歧。这些问题不仅直接影响到对孔南地区油气资源分布的再认识,也严重制约了孔南地区的油气勘探部署与决策。本文针对研究区缺乏野外露头剖面,但地震、岩心、测井与录井及其它资料十分丰富的现实情况,充分利用这些已有的地质资料,在前人研究成果的基础上,以构造地质学、层序地层学和沉积学理论为指导,开展盆地的构造格架、层序地层及沉积体系、原型盆地结构及古构造特征、盆缘类型与盆地的充填样式、盆地演化及物源体系等方面的研究,恢复和重建孔店期盆地结构及盆地演化过程,得出了如下主要研究成果和新认识:1.运用断陷盆地陆相层序地层学的观点建立了孔南地区深层孔店组的层序地层格架,将孔店组划分为一个二级层序、四个三级层序和12个体系域。2.在岩性相、测井相、地震相及古生物等沉积相标志研究的基础上,识别孔店组沉积相类型和进行沉积体系分析,建立了主要沉积相的典型相序。3.根据地震解释剖面分析了孔店期孔南地区沧东断层和徐黑断层等主干断裂在孔店组4个层序发育时期的分段性及活动性特征。4.根据地震解释剖面和编制的黄骅坳陷孔南地区孔店组残留地层厚度图,将孔店期孔南盆地划分为5个凹陷和分割凹陷的4个构造带,其中凹陷分别为沧东凹陷、南皮凹陷、常庄凹陷、小集凹陷和南堤次凹;构造带分别为孔店凸起、东光凸起、王官屯低凸起、舍女寺低凸起。还研究了孔店组4个层序发育时期各构造单元的形成时间及活动特点,分析了凹陷与凹陷、凹陷与构造带及构造带之间的发育关系。5.通过地层厚度图和泥岩厚度图分析,发现孔南地区孔店组沉降中心主要沿沧东断层和徐黑断层的下盘发育,沉积中心则主要分布在盆地中部。沉积、沉降中心有两个方向的迁移规律,一是NE-SW方向的迁移,这表明孔店期沧东断层和徐黑断层拉张走滑的运动学特征;二是NW-SE方向的迁移,表明沧东断层和徐黑断层右行走滑作用的运动学特征。6.在地震剖面解释基础上,分析了黄骅坳陷孔南地区断裂格架、断裂与凹陷之间的对应关系,认为控制孔店组沉积的边界断层为沧东断层和徐黑断层。虽然这两条断层同为控盆断裂,但徐黑断层的活动性相对于沧东断层要弱。同时,孔店晚期孔店凸起在盆地北部逐渐形成。因此,孔南地区孔店组盆地结构北部为“两凹夹一凸”西深东浅的不对称地堑地垒,南部为西深东浅的不对称地堑结构。在原型盆地结构研究的基础上,开展了孔店组4个层序发育时期的盆缘类型与盆地充填样式的研究。7.将孔南地区孔店期盆地作为一个单独的成盆期的新视角来开展盆地演化研究,将其划分为四个演化阶段:早期断陷期、坳陷期、断陷期和断陷充填期。同时分析了每个演化阶段的构造活动与盆地充填特征。分析了湖盆演化的南北和东西方向上的分异性及迁移性特征,主要表现在断层活动性,沉积、沉降中心和湖盆边缘相的分异性及迁移性等方面。8.对盆地演化的控制因素进行了分析,研究指出孔南地区孔店期盆地演化过程主要受构造活动和气候因素的影响,特别是边界断层的控制,其次还受到古地形、盆地的物源体系及湖盆封闭性等因素的影响。探讨了前古近纪基底构造和中生代挤压构造对孔店期沉积的影响,沙河街期以来构造作用对孔店期构造的改造作用。更多还原

【Abstract】 There are abundant hydrocarbon resources in Kongnan area of Huanghua Depression, which is a successor battleground of exploratory and exploitation of reservoir in Dagang Oilfield. Predecessors deal with researching Kongdian period basin in Neozoic basin of Huanghua Depression. Their research is lack about the unique feature of evolution of basin of Kongdian period in Kongnan area. By means of further analysis, we think that thoday’s basin structure is different from Kongdian period basin, which is folded by multiple-period basin and reformed by later basin.At the same time, there are a lot of disagreements from type of basin, sedimentary boundary, provenance system and evolutional phase of basin etc..These problems not only directly influence awareness about distribution of hydrocarbon, but also seriously restrain deployment and decision of hydrocarbon exploration in Kongnan area.On the basis of predecessors’research, and theoretical guidance with tectonics, sequence stratigraphy and sedimentology, the paper sufficiently uses existing seismic section, core, well logging and else datas because of lacking field crop profile to analyze structural framework, sequence stratigraphy, depositional system, prototype basin structure , palaeotectonics feature, type of basin border and filling pattern ,evolution of basin and provenance system of Kongdian period basin in order to recover and rebuild basin structure and process of lacustrine basin of Kongdian period in study area.Through these analysis,we obtain many important conclusions and new recognitions as follows:1. Utilizing land sequence stratigraphy theory of rifted basin to build up sequence strata framework of deep zone Kongdian Formation in Kongnan area, and to divide out one second-order sequence, four third-order sequences and twelve system tracts.2. On the basis of identifying sedimentary facies indexes including lithologic facies, electrofacies, seismic facies and palaeophyte, types of sedimentary facies and sedimentary system are analyzed. Typical facies sequence of main sedimentary facies is built up.3. According to seismic interpretation sections, the characters of segmentation and activity of main faults-Cangdong Fault and Xuhei Fault in developing period of four sequences are analyzed.4. Four second order structural belts and five depressions can be divided from Kongnan basin according to seismic interpretation sections and relict strata isopach map of Ek in Kongnan basin. Four structural belts include Kongdian, Dongguang, Wang guantun and Shenvsi Salient. Five depressions include Cangdong, Nanpi , Changzhuang, Xiaoji and Nandi depression.Formation time and activity feature of each structural unit has been studied in different geologic time of Ek in study area. The growth relationships of depressions, depression and structural belt, structural belts are analyzed.5. Through analysis of isopachous map of strata and mudrock, centers of subsidence of Ek in Kongnan area are found to distribute along Cangdong Fault and Xuhei, depocenters to distribute in center of basin.Centers of subsidence and depocenters have two direction migration laws. One is migration of NE-SW, which indicates tensional and strike slip kinematics characteristics of Cangdong Fault and Xuhei. The other is migration of NW-SE, which indicates right lateral strike slip kinematics characteristics of two faults.6. On the basis of seismic interpretation sections, the paper analyzed the correspond relationships of fault framework, faults and depressions. Boundary fault controling sedimentation of Kongdian formation is Cangdong fault and Xuhei fault. Activity intensity of Xuhei fault is weaker than that of Cangdong fault. At the same time, Kongdian Salient forms gradually in the north of basin. This results an asymmetrical“a salient between two depressions”graben and horst structure in the north, and asymmetrical graben structure in the south.7. Through analyzing the structural development history of crossing main faults, depressions and structural belts , tectonic deformation series of Kongdian period in Kongnan basin can been built to analyze stages and characters of structural evolution. It is an new visual angle that Kongdian formation basin in Kongnan area is as a indepent basin formation phase in order to bring into studying basin structure and lacustrine basin evolution,and to divide it into four evolutional stages including intial rifting stage, depressing stage, rifting stage and rifting-filling stage.The evolutional characteristic of each stage,type of basin margine and filling.Evolution of lacustrine basin has differentiation and migration of north and south, one of east and west.These differentiations and migrations chiefly display in differentiation and migration of fault activity, center of subsidence, depocenter and lake rim facies.8. The research points out that evolution of Kongdian period basin is mainly influenced by tectonic activity, particularly boundary faults, secondly palaeoclimate, ancient landform, provenance systems and closed property of lacustrine basin. Effection to structure of Kongdian period from pre-palaeogene basement structure and Mesozoic compressional structure and reformation from tectonic action of Shahejie phase has been researched.更多还原