宁武盆地构造演化及其对页岩气成藏的控制

发布时间：2018-08-08 18:27

【摘要】：宁武盆地是山西省北部重要的含煤盆地,石炭-二叠纪与侏罗纪地层中富有机质泥页岩非常发育,为页岩气成藏提供了丰富的物质基础。研究宁武盆地构造发育特征、演化规律、页岩气地质特征及构造演化对页岩气成藏的控制作用,对研究宁武盆地构造演化及页岩气进一步勘探开发工作具有重要意义。本论文主要以板块构造理论为指导,在充分研究区域地质构造背景基础上,运用传统地质调查方法,配合室内构造地质学、模拟软件运用等实验手段,对宁武盆地主要地质构造几何学特征、运动学特征及其形成机制特征展开了全面研究,并探讨了地质构造演化对页岩气成藏及其赋存状态的控制作用。主要获得了如下几点认识:(1)宁武地区的地层由下古生界寒武系至新生界第四系均有发育。区域目的层主要经历了海西期、印支期、燕山期、喜马拉雅期等多期构造旋回影响。(2)宁武盆地褶皱构造主要为宁武-静乐向斜,位于宁武盆地的中心;断裂构造主要分布在盆地东西两缘,盆地内部断裂构造相对较少;研究区节理走向主要以NE向、NEE向、NW向和近NS向为优选方位,其次为NWW向。(3)宁武盆地构造在空间展布上存在较大的差异。构造演化存在多期次、多方向、多阶段、多性质的发育历程。(4)宁武盆地中生代以来构造演化史可分为五期:印支期近S-N向挤压、燕山早-中期NW-SE向挤压、燕山晚期近E-W向挤压、四川期近S-N向挤压和喜马拉雅期新裂陷形成阶段,其中鄂尔多斯盆地动力学及太行山隆升动力学对宁武盆地主体构造动力学起着决定性控制作用。(5)研究区野外实测剖面目的层厚度介于30~100 m;TOC介于0.11~7.87%,平均值1.92%;有机质成熟度(Ro)均0.5%。目的层主要经历了五个沉积埋藏阶段:海西-印支早期的快速埋藏阶段、印支末期的快速抬升阶段、燕山早-中期的快速埋藏阶段、燕山晚期的缓慢褶皱隆升阶段、四川期-喜马拉雅期的快速抬升剥蚀阶段。有机质热演化主要经历了三个阶段:印支早-中期的快速埋藏演化阶段、印支末期抬升停止演化阶段和燕山早-中期进一步演化阶段,研究区有机质演化主要定型于燕山早-中期末期,且该期也是页岩气主要成藏期。宁武盆地东缘断裂存在构造负反转作用,生成的烃类气体大量逸散;西缘逆冲断裂带和向斜核部为页岩气成藏提供了封堵和圈闭作用,形成良好的构造页岩气藏。
[Abstract]:Ningwu Basin is an important coal-bearing basin in the north of Shanxi Province. Organic matter rich mud shale is very developed in Carboniferous Permian and Jurassic strata which provides rich material basis for shale gas accumulation. It is of great significance to study the tectonic evolution of Ningwu Basin and the further exploration and development of shale gas. Based on the theory of plate tectonics, based on the full study of the regional geological structure background, this paper uses the traditional geological survey method, the laboratory tectonics and simulation software, and so on. The geometries, kinematics and formation mechanism of main geological structures in Ningwu Basin are studied, and the controlling effect of geological tectonic evolution on the formation and occurrence of shale gas reservoirs is discussed. The main results are as follows: (1) the strata of Ningwu area are developed from Lower Paleozoic Cambrian to Cenozoic Quaternary. The regional target layer mainly experienced several tectonic cycles, such as Hercynian, Indosinian, Yanshanian and Himalayan epoch. (2) the fold structure of Ningwu basin is mainly Ningwu-Jingle syncline, which is located in the center of Ningwu basin; The fault structure mainly distributes in the east and west margin of the basin, and the fault structure in the basin is relatively few, the strike of the joint in the study area is mainly in the NE-NE direction and the NW direction and the near NS direction as the preferred orientation. Secondly, NWW direction. (3) there are great differences in spatial distribution of Ningwu basin. There are many stages, directions, stages and properties of tectonic evolution. (4) the history of tectonic evolution in Ningwu Basin since Mesozoic can be divided into five periods: Indosinian near-S-N compression, early to middle Yanshanian NW-SE compression, late Yanshanian near E-W compression, and so on. The near S-N compression stage in Sichuan and the new rift formation stage in Himalayan period, The dynamics of Ordos Basin and uplift of Taihang Mountain play a decisive role in controlling the main structural dynamics of Ningwu Basin. (5) the thickness of target layer measured in the field profile in the study area is between 30 ~ 100mTOC between 0.11 and 7.87, with an average value of 1.92, and the maturity of organic matter is 0.5. The target layer has undergone five sedimentary burial stages: the rapid burial stage in the early Hercynian-Indosinian period, the rapid uplift stage in the late Indosinian period, the rapid burial stage in the early Yanshanian period and the rapid burial stage in the middle Yanshanian period, and the slow fold uplift stage in the late Yanshanian period. The rapid uplift and denudation stage of Sichuan and Himalayan periods. The thermal evolution of organic matter has experienced three stages: the rapid burial evolution stage of Indosinian early to middle period, the uplift and stop evolution stage of late Indosinian period and the further evolution stage of Yanshanian early to middle period. The evolution of organic matter in the study area was mainly defined in the late Yanshanian early to middle stage, and this stage was also the main reservoir forming stage of shale gas. The faults in the eastern margin of Ningwu basin have negative structural inversion and large amount of hydrocarbon gases, and the western margin thrust fault zone and syncline core provide plugging and trap for the formation of shale gas and form a good structural shale gas reservoir.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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