济阳坳陷第三系地层油藏形成机制研究

【作者】 鲁国明；

【导师】 陈广浩；

【作者基本信息】 中国科学院研究生院（广州地球化学研究所） ， 构造地质学， 2006， 博士

【摘要】 本论文以沉积学和层序地层学为理论基础,以三维数值模拟和油气运移物理模拟为技术手段,以研究-实践并进为主线。运用地质、地球物理和分析化验等综合资料,对济阳坳陷的断-拗转型阶段的构造层序及沉积体系作了系统的研究。并在此基础上,开展对储层特征,油气运移、聚集条件和输导体系的深入研究,并以东营凹陷为例模拟油气成藏过程。论文的主要内容和成果包括以下几点: 1.从构造运动和沉积古地理出发,综合分析了济阳坳陷第三系的演化特征,其中包括地层、构造和沉积等多方面的地质要素,并结合前人对构造层序研究的成果,把济阳坳陷划分为四个构造层:基底层、下构造层、上构造层及顶构造层。由于形成不同的构造阶段,每一构造层在地质、地球物理及地球化学方面各有特点。 2.界定了断陷盆地断-拗转型演化阶段是指断陷稳定期至坳陷初始期的过渡阶段。并详细阐述了断-拗转型阶段的基本特征:构造转型期形成大型不整合、盆地结构由不对称半地堑向近对称性转化、主控断裂由北西向北东及北东东向转化、沉积环境由稳定浅水湖泊向河流相转化、盆地充填方式由快速充填向缓慢超覆转化、岩浆活动以喷发为主、强度中等。 3.分析了断-拗转型阶段构造发育的主要特点,及其对圈闭形成和分布的影响。指出了该期地层超覆带分布广泛,是济阳断陷盆地新生代地层超覆最为发育的时期。不同时期、不同级别的地层超覆带的广泛发育为油气运移提供了通道,也为地层油气藏的形成创造了有利的圈闭条件。 4.通过大量的钻井、岩心、测井和地震资料对比分析,将断-拗转型阶段划分为两个二级层序。并进一步分为3个三级层序,分别为:Es2_上一Es1层序,Ed层序,Ng_下层序。由于断-拗转型阶段固有的特点,不同层序内的体系域有的用“三分法”有的用“两分法”。层序的特征包括两个方面:层序结构的平面对称性和地层分布的相对稳定性;地层超覆和削蚀岩层并存且上下叠置发育。 5.断-拗转型阶段形成的第三系地层油藏的油气来源于沙四上亚段、沙三下亚段、沙三中亚段和沙一段。其中沙三下亚段有机质丰度高、生烃潜力大,并且分布稳定,是济阳坳陷优质烃源岩发育的主要时期。 6.断陷盆地断-拗转型阶段油气运移聚集的输导体系主要包括:断裂型输导体系、砂体型输导体系、不整合面型输导体系和复合型输导体系。并详细阐述了各个输导体系的特征。 7.以东营凹陷为例,论述烃源岩排烃作用、断层活动、圈闭形成、油藏保存条件等及这些地质要素在空间上的配置关系。通过模拟实验,分析了东营凹陷的缓、陡坡带上不整合面的油气运移规律,揭示不整合面和古地形对油藏的影响,探讨地层超覆油藏聚集机理,从而指导地层超覆油藏的勘探和开发。更多还原

【Abstract】 In this paper, based on sedimentology and sequence stratigraghy, three dimensional numerical simulation and petroleum migration physical analogue as technical measure, study and practice as mainline. Integrated information about geology, geophysical and assaying, study structural sequence and sedimentary system of transition period of fault sag in Jiyang depression。 Based on the conditions, reservoir feature, petroleum migration and accumulation conditions and passage system were thoroughly analyzed, petroleum pool-forming process was modeled taking Dongying depression as an example. Several achievements and conclusions had been obtained in this paper as follows:1.Considering the tectonic movement and ancient geography, this paper comprehensively analyses the features of the evolution of tertiary in Jiyang depression, the features includes strata, structure and sediment etc, and combines the research findings of structural sequence that was studied by predecessors, tertiary of Jiyang depression is divided into four structure layer including basal stratum, infrastructure, up structural layer and top structural layer. every structural layer has different geology, physical geography and geochemistry feature. These structal layers are different from each other in geology, geophysical and geochemistry, since they underwented different tectonics.2.Difine that transitive stage of fault sag in fault basin is from the stable stage of fault subsidence to the initial stage of depression. And elaborates the basic feature of transitive stage of fault sag, structural transitional stage formed large-scale unconformity, basin structure translated from asymmetry half graben to approximate symmetry half graben, main control rupture translated from northwest to northeast and east northeast, sedimentary environment translated from shallow water lake facies to fluvial facies, filling model of basin translated from quickly filling to slowly overlapping, magmatic activity gived priority to eruption and was medium intensity.3.Analyses main structure feature of transitive stage of fault sag and the feature effected reservoir formation and distribution.Strata overlap belt of transitive stage of fault sag widely distributed, this stage was the very development period of strata overlap of Cenozoic strata in Jiyang depression. The wide development strata overlap belt of different period and different level provided passage for petroleum migration, created beneficial reservoir conditions for strata reservoir formation.4.This paper correlated and analyzed a lot of drilling, coring, well logging and seismic data, the transitive stage of fault sag was divided into two 2nd -order sequence. And further divided into three 3rd-order sequence, including Es2s-Esl sequence, Ed sequence, Ngx sequence. Due to own feature of the transitive stage of fault sag, systems tract of different sequence adopted trichotomy and dichotomy. Characteristic of sequence contained two respects: plane symmetry of sequence structure and relative stability of strata distribution, strata onlap and truncation strata superposed development.5.Oil and gas of transitive stage of fault sag derived from Es4s, Es3x, Es3z and Es1. Organic matter abundance of Es3x is high, potentiality of generating hydrocarbon is great and distribution is stable. Es3x is the main period of goodness hydrocarbon source rock development in Jiyang depression.6.Passage systems of petroleum migration and accumulation of the transitive stage of fault sag in fault basin included rupture passage system, sandstone passagesystem, surface of unconformity passage system and complex type passage system. And circumstantiated the feature of every passage system.7.Taking the Dongying depression as an example, discussed hydrocarbon expulsion action and faults activity and formation of the traps and conservation conditions and spatial relationship of geologic feature. Analyzed migration regularities through unconformity of gentle slope and steep slope in Dongying depression by indoors simulating experiments, revealed the relation of unconformity and palaeotopography with oil reservoir, discussed mechanism of accumulation of strata overlapping oil reservoir, and they were helpful for exploration and exploitation更多还原