【作者】 王磊；

【导师】 吕延防；

【作者基本信息】 大庆石油学院 ， 油气田地质工程， 2007， 博士

【摘要】 准噶尔盆地南缘(简称准南)是我国中西部前陆盆地油气勘探的一个重要领域,目前针对该地区所面临的断裂与油气成藏和保存的关系不清晰等问题,本文以断层相关褶皱理论、断裂控藏理论为指导,详细研究了断裂与圈闭的形成与演化的关系,断裂与油气运聚和保存的关系,建立了准南前陆冲断带的油气运聚成藏模式。准南前陆冲断带断裂活动期次可分为4个期次,石炭世被动大陆边缘阶段张性正断层形成时期、晚石炭世-二叠纪周缘前陆盆地阶段逆冲断裂形成时期、白垩系构造挤压断裂活动时期和晚第三纪以来再生前陆盆地逆冲断裂形成时期。并依据断裂的断穿层位划分为基底卷入型断裂和以三套滑脱层为滑脱面的滑脱断裂。根据断层相关褶皱理论和冲断带上的地震剖面,分析了基底卷入型和盖层滑脱型构造样式的形成和发育过程,明确了构造样式分区分带的特征。准南前陆冲断带油气具有多期成藏和晚期为主的特点,早期油气运移通道主要是砂体和不整合面,向古隆起方向侧向运移;再生前陆盆地时期油气运移主要通道为断裂,以垂向运移为主,此时期错过了主力烃源岩大量生排油时期,因此断裂表现为调整和破坏早期油气藏、形成次生油气藏的过程。从圈闭的形成时间,空间展布,成藏过程和要素组合条件出发,详细分析了各种圈闭的有效性,认为只有这四个方面都是有效的圈闭才是冲断带上可钻探的目标,结合油气成藏过程,提出四种有利的目标模式:(1)新近纪形成的薄薄叠加型构造样式的中构造层中的圈闭;(2)受盖层限制的基底卷入型构造样式含油气性普遍较好,目的层集中在中下构造层;(3)厚-薄叠加型构造样式中下构造层圈闭,如果位于油气运移路径上,其含油气性可能很好;(4)继承性发育的基底卷入型构造样式的下部构造层中,早期有油气的聚集,晚期断裂没有破坏圈闭完整性的圈闭。分析了断裂带内部结构和封闭机理,明确了断层封闭的类型,建立了适合于中西部前陆盆地断层封闭性评价方法,并对安集海背斜、卡因迪克背斜和西湖背斜断层封闭性进行了评价,结果表明,准南前陆盆地断裂主要为泥岩涂抹和层状硅酸盐/框架断层岩封闭,同一条断裂不同层段,同一层段的不同位置,其封闭性存在很大的差异。准南前陆冲断带油气成藏主控因素为:有效源岩的范围控制着油气的分布、古隆起控制着早期油气运移方向和分布、油源断裂控制着晚期油气的分布、优质盖层是油气充注和保存的关键因素、断层的封闭性控制着油气聚集的层位。利用断裂本身错动面积及倾角大小能反映断裂输导油气的能力的性质,对断裂输导能力进行了定量评价。提出了考虑断层垂向封闭性和盖层品质综合评价盖层阻烃能力的方法,并对准南再生前陆盆地时期盖层阻烃能力进行了评价。依据有效烃灶、高效输导和有利保存条件,预测准南前陆冲断带有利的富集区域主要分布在第二排构造带和第三排构造带上。更多还原

【Abstract】 The southern Junggar foreland basin is an important oil and gas exploration field for the foreland basins in central and western China. In view of the problem that the relation of fracture, hydrocarbon accumulation and preservation is not clear at present, under the guide of fault-related folding theory and fault control hydrocarbon theory , the relationship of faults and the formation and evolution of traps, hydrocarbon migration and preservation had been studied detailly in this paper, and the models of reservoir migration and accumulation in the southern Junggar foreland basin wrere established.The active period of foreland thrust belt in southern Junggar foreland basin were divided into four stages: (1)normal fault-phase formation period of Carboniferous passive continental margin stage;(2) thrust fault formation period of Late Carboniferous-Permian peripheral foreland basin stage ;(3)faults’activities period of Cretaceous tectonic compression stage;(4) thrust fault formation period in renewable foreland basin since the late Tertiary. According to the fault active period and the layer broken by the fault, the faults were divided into two major type,basement-involved faults and detachment faults with detachment surfaces formed by three sets of detachment layers. According to the theory of fault related fold and the seismic profile, the formation and development process of basement-involved style and caprock detachment is analyzed, the features of partition and zone of tectonic style is defined.Oil and gas were characterized as multi-period accumulation and mainly formed in late period in thrust belt of Southern Junggar foreland basin, early paths of hydrocarbon migration were mainly sand bodies and unconformity surfaces, oil and gas migrated laterally to ancient uplift. In the period of regenerated foreland basin, the main paths of hydrocarbon migration were faults, oil and gas mainly migrated in vertical direction. The period of regenerated foreland basin missed the period of abundant hydrocarbon generation and expulsion from main source rock, the process of adjusting and damaging early reservoir by faults begins, and then secondary reservoir was formed. With respect to the formation time, spatial distribution, migration and accumulation process, reservoir and seal conditions of trap, the effectiveness of various traps was analyzed, it’s considered that the drilling target in the thrust belt was the trap with all four aspects mentioned above, indicating the four types of favorable target models are: (1) trap in tectonic layers in thin-thin superimposed style formed in the Neogene; (2) the tectonic style of basement-involved structural style restricted by caprock generally involve better content of gas and oil, where formation of interest assembles in the mid-lower structure layers; (3) the lower tectonic layer traps in the thick-thin superimposed structure style may be favorable mode, if located in hydrocarbon migration path, the mid-lower structure of hydrocarbon-bearing layer is good; (4) the low part of tectonic layers in the basement-involved structural styles of inherited development, oil and gas accumulated in the early time ,while trap’s integrity not undermined in late time.The internal structure and sealing mechanism in southern Junggar foreland basin was analyzed, the type of fault sealing and the evaluation method of fault sealing suitable to the Central and Western Areas of foreland basin is established. Also the fault sealing of Anjihai anticline, Kayindike anticline and West-Lake anticline is evaluated. It’s considered that the main type of the fracture were sealed by clay smear and phyllosilicate /framework fault rock. The sealing ability of fault vary greatly for the same fault of different l formation as well as the same formation of different location .The main control factors of hydrocarbon accumulation in the thrust belt of Southern Junggar foreland basin: effective hydrocarbon controlled distribution of oil and gas; paleohigh control the early direction of hydrocarbon migration and distribution; oil sources faults control the distribution of late hydrocarbon; high-quality caprock becomes a critical factor for charging and preservation of oil and gas,fault sealing control the accumulation layer of oil and gas. Using the slippage area of faults and inclination reflecting transporting ability of oil and gas, the quantitative evaluation to fault transporting ability in the thrust belt of southern Junggar foreland basin was made. By proposing the method of evaluating the sealing ability of caprock to hydrocarbon allowing for fault vertical sealing and caprock quality, the comprehensive evaluation to the sealing ability of caprock to hydrocarbons, which were in the period of each renewable foreland basins, was made. According effective hydrocarbon, and efficient transporting and favorable preservation conditions, favorable enrichment region mainly distribute in the second and the third tectonic zone in the thrust belt of southern Junggar foreland basin is forecasted.更多还原