渝东北地区构造特征与页岩气富集关系研究

发布时间：2018-02-15 04:39

本文关键词： 渝东北页岩气构造样式保存条件有利区预测　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：论文以矿物岩石学、石油地质学、构造地质学等相关学科作为理论依据,结合室内实验与野外剖面观察,分析区域地质背景和区域构造演化史;通过渝东北地区的构造样式、断裂特征、裂缝特征等,来研究构造特征对页岩气富集、保存条件的影响。最后根据页岩气构造保存条件预测有利区块,为渝东北地区的页岩气勘探提供地质依据。渝东北地区位于大巴山逆冲推覆带前缘,横跨秦岭地层区与扬子地层区。研究区的地层除泥盆系、第四系缺失外,整体都有出露。城巴断裂将渝东北地区分隔为北大巴山逆冲推覆构造带和南大巴山前陆褶皱冲断带两个一级构造单元。其中南大巴山前陆褶皱冲断带沿坪坝断裂和鸡鸣寺断裂划分为叠瓦断层带、断层-褶皱带和滑脱褶皱带三个次级构造单元。北大巴山推覆构造带整体为复式背斜,断层的显著发育表明该区经历强烈的冲断作用。南大巴山断褶带的构造样式是“逆冲褶皱组合”,形成逆冲断层系统,冲断褶皱系统和滑脱褶皱系统三类构造组合。研究区裂缝发育明显,以小型裂缝和中等尺度裂缝为主,大尺度裂缝发育较差,裂缝类型包括构造缝及成岩缝,其中主要以构造缝为主。裂缝充填程度高,充填物主要为方解石及少量石英和黄铁矿。渝东北地区富有机质页岩层厚度较厚,埋藏深度在250m-4000m,烃源岩热成熟度处于高成熟度-过成熟度之间,区域盖层总体较好,有利于渝东北地区的页岩气保存与富集。根据对渝东北地区构造特征的分析,选择下寒武统水井沱组、鲁家坪组和上奥陶统五峰组-下志留统龙马溪组为主要勘探目的层系。优选出下寒武统页岩气资源分布有利区为巫溪周围地区及开县西北部、满月乡西南部。上奥陶统-下志留统页岩气资源分布有利区为巫溪县西南方向,处于红岩向斜核部地区和开县境内满月乡附近。
[Abstract]:Based on the related disciplines of mineral petrology, petroleum geology, tectonic geology and so on, the paper analyzes the regional geological background and the history of regional tectonic evolution through laboratory experiments and field profile observation. In order to study the influence of structural characteristics on the accumulation and preservation conditions of shale gas, the fracture characteristics and fracture characteristics are studied. Finally, the favorable blocks are predicted according to the structural preservation conditions of shale gas. It is located in the front edge of Dabashan thrust nappe belt, straddling Qinling stratigraphic area and Yangtze formation area. The strata of the study area except Devonian and Quaternary are missing. The Cityba fault divides the northeast of Chongqing into two first-order tectonic units: the North Dabashan thrust nappe belt and the southern Dabashan Foreland fold thrust belt, in which the southern Dabashan Foreland fold thrust belt along the Pingba fault. The Hejinmingsi fault is divided into the imbricate fault zone, Three secondary tectonic units, fault-fold belt and slip fold belt. The northern Dabashan nappe belt is a composite anticline. The obvious development of the fault indicates that the area experienced strong thrust. The structural style of the South Dabashan fault fold belt is "thrusting fold assemblage", forming a thrust fault system. There are three types of structural assemblages of thrust fold system and slip fold system. The fractures in the study area are obviously developed, mainly small and medium scale fractures, but poor in large scale fractures, and the types of fractures include structural fractures and lithogenic fractures. The fracture filling degree is high, the filling material is mainly calcite, a small amount of quartz and pyrite, and the thickness of organic matter rich shale is thicker in the northeast of Chongqing. The buried depth is between 250m and 4000m, the thermal maturity of hydrocarbon source rock is between high maturity and overmaturity, and the regional caprock is good, which is beneficial to the preservation and enrichment of shale gas in northeast Chongqing. The lower Cambrian Shuituo formation, Lujiaping formation and Upper Ordovician Wufeng formation and Lower Silurian Longmaxi formation are selected as the main exploration target series. The favorable area of shale gas resources distribution in Upper Ordovician and Lower Silurian is southwest of Wuxi County, located in the core area of Hongyan syncline and near Manchue Township in Kaixian.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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