【作者】 李晓清；

【导师】 王先彬； 周瑶琪； 才汝成；

【作者基本信息】 中国科学院研究生院（兰州地质研究所） ， 地球化学， 2002， 博士

【摘要】 在对含油气盆地进行油气地质评价和优选勘探目标时，通常要解决三个层次的地质问题，即盆地评价(主要涉及盆地的油气资源评价、勘探潜力评价以及勘探经济评价)、区带优选和钻探目标确定。目前流行的评价研究思路是从动力学角度，研究涉及盆地的成因及其类型、盆地演化的深部控制因素、盆地演化的过程序列、盆地沉积充填的动力学特征、盆地流体的运动学和动力学以及定量动力学模拟等诸多方面。走滑盆地作为沉积盆地的类型之一，其丰富的油气资源已被国内外勘探和研究所证实。近年来，中国海洋石油公司和菲利普斯公司合作，在中国东部海域发现了蓬莱19-3大油田，进一步证实了与郯庐走滑断裂伴生的沉积盆地和构造带富含油气，同时也要求人们按照含油气系统等先进理论和研究方法，去深化研究与郯庐断裂带相关的走滑盆地油气资源潜力和有利区带评价，进一步开拓相关领域的油气勘探。 潍北盆地是位于郯庐断裂带内部的沉积盆地。几十年来的勘探证实了该盆地富含油气。长期以来，人们对盆地的性质、形成演化以及油气潜力和油气赋存的规律缺乏足够的认识，使得对该盆地油气勘探进入艰难时期。本文以沉积盆地动力学研究为指导思想，采用走滑盆地构造解析、层序地层学以及含油气系统等研究方法，研究潍北盆地的形成演化，分析该走滑盆地油气潜力和油气分布规律，指出深化该盆地油气勘探的有利领域。本文在大量的第一手资料基础上，通过深入分析，建立了盆地形成演化的动力学过程；明确了有效烃源岩的地化特征及其分布；模拟了成烃演化历史，确定了油气成藏的关键时刻和含油气系统边界；探讨了油气的成因；总结了油气藏分布规律，提出了有利勘探领域。 本文取得的主要成果与认识如下： 1．潍北盆地是受郯庐断裂走滑作用控制的走滑伸展盆地(或可称之为拉分盆地)。盆地构造演化经历了五个阶段：①白垩纪走滑裂陷期，以发育巨厚的火山岩和火山碎屑岩为特征；②孔三段沉积期的走滑裂陷作用，奠定了盆地的构造格局；③孔二段～沙河街沉积期，以拉张断陷作用为主，是盆地形成的重要时期；④渐新世沙河街晚期，走滑挤压作用；⑤晚第三纪，盆地进入区域坳陷沉降阶段和挤压阶段。 2．在地震地层学分析、单井高分辨率层序地层分析基础上，将盆地充填地层划分出6个层序界面、2个二级层序和6个三级层序，建立了层序地层格架。指出裂陷沉降期形成的SQ2层序，沉积环境由浅湖向半深湖一深湖发展，是生油岩形成的主要时期。SQ3、SQ4层序的两个低位体系域沉积的扇三角洲和浊积扇砂体是主要的储集层。 3．在样品实验分析基础上，从有机质分布、有机质类型、丰度及成熟度等方面，系统论述了孔店组孔二段烃源岩的地球化学特征。指出了孔二段源岩有机质丰度高，类型以IllJI型为主，是一套有效的烃源岩，其中孔H上段油页岩为优质烃源岩。从镜质组反射率和有机质的转化程度来看，潍北盆地孔二段源岩在1300米埋深己处低熟生烃阶段，1700米己达成熟生烃阶段，3300米进入高熟生烃阶段。3 4．采用的镜质体反射率正演模型技术，对不同构造单元的重点探井（央5井、昌 32、昌 52、昌 67、瞳 4）的烃源岩热演化进行模拟计算。研究认为北部洼陷孔二段成烃时间早，在孔一段沉积早中期进入低成熟门限，沙四段早期进入成熟l’刁限，馆陶组末期和明化镇组早期达生烃高峰期。现今孔二段大部分处于生烃高峰演化阶段。瓦城断阶的昌52井以南包括南部斜坡在内的孔二段烃源岩现今仍处于低熟阶段，对油气成藏贡献不大。同时，指出盆地东南部以昌25井为中心的烃源岩成熟区，异常的热源（由岩浆活动引起）对该区烃源岩成熟有重要贡献。 5．明确提出潍北盆地存在以北部洼陷为主和东南部灶户地区为辅的两个有效生烃灶；结合烃源岩热演化，指出孔二段含油气系统形成关键时刻为沙河街组末期和现今；油气运移通道主要有三类，即断层、砂岩层及不整合面；确定了含油气系统在平、剖面上的分布。 6．潍北盆地石油可分为低熟油、成熟油两类，腐泥型十偏腐殖型烃源岩是潍北盆地南部地区低熟油的主要源岩。采用多种地球化学指标，进行了油一源对比。气一源对比，认为潍北革地的油气运移距离较近，为近源油藏。 7．潍北盆地天然气成因类型复杂。根据天然气组分和碳一氢同位素特征，可划分为细菌气、细菌一成熟油型气、低熟煤型一油型气、成熟油型一煤型气和高熟煤型气五种类型。不同类型天然气平面上呈带状分布，盆地南部斜坡主要为细菌气，中部主要为低熟煤型一油型气和成熟油型一煤型气，北部深洼陷区主要为煤型气。 8．在对灶户断鼻及南部柳瞳油气藏的解剖基础上，总结潍北盆地油气富集规律。提出了七个有利勘探区带：①灶户断鼻构造带；②东利鱼一灶户断层转化带；③北部洼陷带岩性圈闭群；④瓦城断阶带东利鱼以西地区；⑤南部斜坡带天然气；③孔三段玄武岩不整合油气藏；①盆地外围，包括潍北凸起和潍北侯镇结合部。更多还原

【Abstract】 In the process of petroleum geology assessment and exploration target optimization, three aspects of geological factors need more attention, ie. basin evaluation (in relation to hydrocarbon resources, exploration potential, and exploration economics), play optimization and prospect determination. Thfe comprehensive study aspects currently in fashion are characterized by basin genesis and type, deep controlling factors for basin evolution, a series of evolution events, dynamic features of basin filling, fluid kinematics and dynamics, and quantitatively dynamic simulation, and so on. Strike-slip basins being one kind of sedimentary basins play an important role in huge hydrocarbon discoveries.In recent years, the successul coopeartion between CNOOC and America-based Philips saw the discovery of Penglai 19-3 Oilfield which is located in offshore territory of EastChina, as strengthens the evidences of hydrocarbon accumulatiom existing in some sedimentary basins and structural zones associated with Tanlu strike-slip faulting. In general, the above mentioned recognition will surely widen our next exploration targets and adjust our thinking way to comprehensively study hydrocarbon resources potential and favorable petroleum zones in the strike-slip basins in relation to Tanlu Fault through the application of anvanced exploration theories and methods such as the concept of petroleum system.Weibei Basin is one of the sedimentary basins within Tanlu Fault Zone. Several decades of exploration practices make people believe that this basin bears abundant petroleum resources. The petroleum exploration in this basin becomes more and more difficult because of low level of understanding of evolution history, petroleum potential and hydrocabon distribution law of Weibei Basin. This paper is based on Dynamics of Sedimentary Basin to apply structural interpretation, sequence stratigraphy and petroleum system specially for strike-slip basins to the comprehensive analyses of Weibei Basin, furtherly target some favorable prospects. A lot of first hand data are successful in establishing the dynamic evolution process, making clear the geochemical features and distribution law of effective source rocks, simulating hydrocarbon generation evolution, and determining the controlling factors of hydrocarbon accumulation and the petroleum system boundaries of Weibei Basin. As leads to concluding the distribution law of hydrocarbon accumulations and proposing new favorable exploration zones.The leading conclusions drawn from the above analyses are as follows: 1. Weibei Basin, catelogued as pull-apart basin, is a stretching strike-slip basin whose growth and formation is controlled by Tanlu strike-slip rifting. Weibei’s structural evolution underwent 5 stages: (1) strike-slip rifting during cretaceous, which is characterized by development of hugely thick volcanic and volcaniclastic rocks; (2) strike-slip rifing and depressing during the 3rd member of Kongdian Formation, the general structural framework was established; (3)-3-During the sedimentation of the 2nd Member of Kongdian Formation and Shahejie Formation, extentional faulting and depressing movement prevailed in this important stage of basin formation; (4) during Oligocene, ie. the latest stage of sedimentation of Shahejie Formation, strike-slip compressing played more actively; (4) during Neocene, the whole basin entered into its regional subsidence and compression development stage.2. On the basis of the comprehensive analyses of seismic stratigraphy and high resolution sequence stratigraphy for individual well, the filling successions are classified into 6 sequence boundaries, 2 second class sequences and 6 third class sequences, and the sequence stratigraphy framework was constructed. The basin’s sedimentary environment developed from shallow to half-deep, deep lacus during rifted subsidence which formed significant source rock SQ2. Fan deltas and turbidite fan sand bodies are predominant reservoirs which were deposited in two low stand tracts SQ3 and SQ4.3.更多还原