金湖凹陷断裂成因与构造演化分析

发布时间：2018-01-29 04:58

本文关键词： 金湖凹陷断裂成因构造演化断裂系统数值模拟　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：苏北盆地是杨子板块上为数不多的几个陆相含油气盆地之一,金湖凹陷是该盆地内最重要的油气产区之一,其油气成藏与盆地断裂系统具有密不可分的关系,但该凹陷的断裂构造长期以来一直缺乏系统、深入的认识。本文在区域动力学背景分析的基础上,通过对典型剖面的构造精细解释、剖面和平面构造样式解析、断层活动性及构造演化分析,重点开展了成盆期的应力场模拟、断裂形成过程的数值模拟等研究,阐明了金湖凹陷内断裂系统的成因及演化历史。金湖凹陷发育有杨村、铜城和石港三大断裂系统,这些断裂系统在成盆前及成盆期经历了多期构造演化阶段。区域构造分析及断裂模拟结果表明,杨村断层西段(汊涧断层)、石港断层与铜城断层均为晚白垩世-古近纪成盆前的基底断层复活的产物,其中石港断层与汊涧断层的前身为印支期苏鲁造山带南缘前陆变形带上的同一条前陆逆冲断层,在晚白垩世-古近纪成盆期间发生断层复活,由逆冲断层转变为控盆/控洼铲形正断层。铜城断层的前身为晚侏罗世的左行平移断层,平移期将汊涧断层与石港断层左行错开,并在晚白垩世-古近纪成盆期间转变为汊涧断层的释放断层。杨村断层的东段形成于晚白垩世-古近纪成盆期间,为汊涧断层强烈拉张下的扩展断层。一系列证据表明,金湖凹陷在晚白垩世-古近纪成盆期间处于近SN向的拉张应力场中,在此区域应力背景下,杨村、铜城与石港断层的主干断层旁侧分别发育了特征性的羽状断层或雁列状断层,本文的数值模拟结果再现了这些次级断层的形成过程与发育机制,对三大断裂系统构造样式的成因给出了合理的解释,详细阐述了凹陷内各方位断裂的成因特征。金湖凹陷自晚白垩世以来经历了多期成盆与反转事件,自下而上发育有三套构造层,在剖面上形成了三套截然不同的构造系统,相应地盆地经历了泰州-阜宁期的分散断陷、戴南-三垛期的集中断陷与盐城期的坳陷阶段。断层活动性分析表明泰州-阜宁期为同沉积伸展断层启动阶段,戴南-三垛期为伸展断层强烈活动阶段,盐城期在弱伸展作用下(SN向拉张)盆地趋于消亡、断层活动趋于停止。戴南-三垛沉积期与盐城沉积期之间的三垛事件(NEE向挤压)造成了盆地的强烈反转,铜城断层因其独特的走向方位与断层性质,在三垛事件中由成盆期的释放断层(正断层)转变为典型的逆断层,是苏北盆地内为数不多的逆断层之一。总体上看,金湖凹陷内的断裂系统是在基底断裂控制下多期演化的结果,晚白垩世-古近纪成盆期间在区域近南北向拉张的应力场下发育了一系列次级断层,从而形成了复杂的断裂构造系统。金湖凹陷的断裂系统在成盆前主要经历了印支期前陆逆冲和燕山期左行平移两个构造演化阶段(基底主干断层形成阶段),成盆后经历了阜宁期初始伸展阶段(盆地分散断陷阶段)、戴南-三垛期强烈伸展阶段(盆地集中断陷阶段)、三垛事件断层反转阶段及新近纪以来的弱伸展-消亡阶段(盆地坳陷-消亡阶段)。
[Abstract]:The northern Jiangsu Basin is Yang Zi plate is one of the few continental petroliferous basin in the number of Jinhu sag is one of the most important oil and gas producing areas of the basin, the hydrocarbon reservoir and the fault basin system has a close relationship, but the fault depression has long been lack of systematic, in-depth understanding of the foundation. This paper analysis on regional dynamics background, through the fine structure interpretation of the typical profiles, profile and plane structural style analysis, analysis of the evolution of fault activity and structure, focus on the stress field simulation of basin, research on Numerical Simulation of the process of crack formation, expounds the origin and evolution of faults in Jinhu sag the history of the system. Jinhu sag is Yang Cun, Tongcheng and Stone Harbor three fault system, the fault system in the basin and basin forming period experienced multi-stage tectonic evolution stages of tectonic analysis and fault. The simulation results show that the crack, West Yangcun fault (Chajian fault), Shigang fault and Tongcheng fault are late Cretaceous - Paleogene basin basement faults before the product of resurrection, of which Shigang fault and fault Chajian formerly known as the Su Lu orogenic belt of the Indosinian foreland deformation with a foreland zone the thrust faults during the Late Cretaceous to Paleogene faulted basin raised by thrust faults into the basin controlling / control wa listric normal fault. Tongcheng fault was sinistral fault in Late Jurassic period, the translation will Chajian fault and Shigang fault left staggered. And during the late Cretaceous Paleogene basin into fault Chajian release faults. The faults formed in the eastern section of Yang village during the late Cretaceous Paleogene basin, Chajian fault for strong pull fault under expansion. A series of evidence that Jinhu sag in Late Cretaceous Paleogene Paleogene basin forming period Is close to SN the tensile stress field in this area should be Yang Cun, Tongcheng and force under the background, the main fault of Shigang fault were developed flanking characteristic pinnate fault or en echelon fault, the results of the numerical simulation reproduces the formation and development mechanism of these secondary faults, causes are given of the three major fault systems of structural styles explained and elaborated formation characteristics of each fault depression range. Jinhu depression since the late Cretaceous basin experienced multi period and reversal events, bottom-up develops in three tectonic layers, forming three distinct tectonic system in the section, the basin Taizhou - Funing experienced dispersed phase fault depression, Dainan Sanduo period - three concentrated period of Yancheng fault depression and depression stage. The fault activity analysis showed that the Taizhou - Funing period synsedimentary extensional fault start-up phase, Dainan - three For a period of intense activity duo extensional stage, Yancheng in the period under the weak extension (SN tension) basin tends to disappear, the fault activity tends to stop. A South - between three and Yancheng duo sedimentary stage in the sedimentary period of the three events (Duo NEE compression) caused strong inversion, Tongcheng fault because of its unique the orientation and the nature of the fault, in three by the release of fault events duo basin period (fault) into reverse fault in Northern Jiangsu Basin is typical, as one of the few thrusts. On the whole, the fault system in Jinhu depression is in the evolution of multi period results of basement fault control and the late Cretaceous Paleogene basin during the regional north-south extensional stress field under the development of a series of secondary faults, thus forming a complex fault system. The fault system in the Jinhu sag basin before experienced Indosinian foreland thrust and Yanshan During the period of sinistral two tectonic evolution stages (basal main fault formation stage), after a period of Funing basin (basin extensional stage initial rifting stage, dispersion) - three Dainan Sanduo period strong extensional stage (central basin rift stage), three duo event fault inversion stage and Neogene weak the extension and extinction stage (Basin - extinction stage).

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13;P542

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