【作者】 王丽静；

【导师】 张明学； 梁江平；

【作者基本信息】 大庆石油学院 ， 地球探测与信息技术， 2007， 硕士

【摘要】 论文以层序地层学为基本理论和研究方法,在前人研究成果的基础上,结合现代地球物理理论和构造理论,对徐家围子断陷西部的地层格架进行了深入研究和分析,并取得了一些认识。根据地震剖面和钻测井资料所反映的地层之间的接触关系及层序的沉积特征进行层序界面的识别和层序划分,共划分了4个超层序和8个三级层序,建立了徐家围子断陷西部的地层格架。通过制作构造图和构造发育史剖面图对地层格架内重要界面的构造特征和构造演化进行研究。徐家围子断陷西部主要受北北西走向的徐西大断裂控制,并在断裂活动的同时伴随火山喷发。圈闭类型以背斜和断鼻圈闭为主,大部分圈闭受断层控制,分布在断层的边缘及古凸起上。该区的构造演化经历了强烈断陷期、断坳转换期、坳陷期和挤压褶皱期4个演化阶段。对三级层序的沉积特征进行分析,认为火石岭组和营城组一段以火山岩相为主,沙河子组下段、沙河子组上段和营城组四段分别以扇三角洲、深湖-半深湖和三角洲相为优势相,而登娄库组则为河流相。并对碎屑岩沉积的三级层序进行了体系域划分,一个完整的三级层序分为低水位体系域、水进体系域、高水位体系域。影响徐家围子断陷西部层序发育的因素包括构造、气候、沉积物供给速率、湖平面变化和火山喷发,在断陷期构造因素为主控因素,而在断坳转换期气候因素的影响逐渐变大。上述诸因素通过综合作用影响着基准面和可容空间的周期性变化,进而控制着各级层序的发育和内部结构特征。综合分析构造和层序沉积特征,并对生储盖组合和超覆圈闭进行了分析与预测,认为徐家围子断陷西部有利的勘探区带分布在肇州西凸起区、昌德凸起区、中内泡凸起区和徐西断裂地层超覆区。更多还原

【Abstract】 Based on a mass of previous achievements, the thesis has studied the stratigraphic framework of the strata in the west of Xujiaweizi fault depression with the fundamental principle and methods of sequence stratigraphy, combining modern geophysical theory and tectonic theory, and has got some elementary conclusions.The strata in the west of Xujiaweizi fault depression is divided into 4 super-sequences and 8 third-order sequences according to the contact relations of the strata which are reflected from seismic section, drilling data and log data. Accordingly the stratigraphic framework is set up in the west of Xujiaweizi fault depression.The tectonic characteristics of the critical boundaries of stratigraphic framework and structure evolution are studied through the establishment of structure map and structural history profile. The strata in the west of Xujiaweizi fault depression were controlled by NNW Xuxi fault, and volcanic outbreak accompanied the fault activities. The anticline and fault-nose are the main and vast trap. A majority of traps are influenced by fault, and locate on the edge of faults and the top of paleo-bulges. The structure evolution process experienced 4 stages: intensively faulting period, the period transformed from fault depression to sag, depression period and compaction fold period.According to the analysis of the sedimentary characteristics of third-order sequences, it is thought that volcanic facies is the main sedimentary environment in Huoshiling formation and in the first section of Yingcheng formation. In the lower section of Shahezi formation, the upper section of Shahezi formation and the forth section of Yingcheng formation, the main sedimentary environment is fan delta facies, deep and semi-deep lake facies and delta facies respectively. Fluvial facies develops in Denglouku formation. Besides, systems tract is studied in third-order sequences which filled with clastic rocks. An intact third-order sequence is divided into lowstand systems tract, transgressive systems tract and highstand systems.The development of sequence in Xujiaweizi fault depression is controlled by tectonic factor, climate factor, sediments supply rate, lake-level change and volcanic outbreak. The tectonic factor is the main affecting factor in faulting period, but in the period transformed from fault depression to sag, climate factor becomes more significant. All the above factors comprehensively interact each other to affect the periodical change of base-level and accommodation, in turn, control the development of sequence and the features of its internal structure.It concludes that the favorable zones for prospecting locate at Zhaozhouxi bulge, Changde bulge, Zhongneipao bulge and overlap area of Xuxi fault, which is educed by the synthetical study of tectonic characteristics, sequence sedimentary characteristics, source-reservoir-caprocks assemblage and overlap trap.更多还原