小纪汗井田中侏罗统延安组层序地层研究

发布时间：2018-07-15 08:13

【摘要】：论文以钻孔岩芯描述、测井曲线分析和测试分析为基础,对鄂尔多斯聚煤大型盆地榆横煤田小纪汗井田中侏罗统延安组沉积相、层序地层进行了研究。在层序格架内,综合地层厚度、砂岩厚度、泥岩厚度、含砂率和煤层厚度等因素,分析了延安组沉积期不同层序的古地理特征与沉积演化,探讨了层序格架内聚煤规律。在研究区延安组识别出曲流河、辫状河、三角洲和湖泊4种沉积相、10种亚相、23种微相,总结了不同沉积相的特征。依据层序地层学原理,将研究区延安组划分为6个层序、15个体系域,建立了研究区层序地层格局。层序发育主要受构造升降、湖平面变化、古气候、沉积物通量与可容纳空间等因素控制,构造升降是最主要控制因素。以体系域为单位,系统研究了延安组不同沉积期的古地理特征,研究区延安组沉积期经历了湖泊初始充填、湖泊扩张、湖泊萎缩、湖泊萎缩期后等四个阶段,建立了延安组沉积相模式。总结了延安组主要煤层的聚煤规律,建立了曲流河岸后河漫沼泽、湖湾泥炭沼泽、三角洲前缘分流间湾泥炭沼泽和三角洲平原分流间洼地泥炭沼泽4种聚煤模式;富煤期间为最大水进面体系域,最佳富煤带为井田西及西北部。
[Abstract]:Based on drilling core description, log curve analysis and test analysis, the sedimentary facies and sequence stratigraphy of the middle Jurassic Yanan formation in Yuheng coalfield of Yuheng coalfield, Ordos coal accumulation large scale basin, are studied in this paper. In this paper, the paleogeographic characteristics and sedimentary evolution of different sequences of Yanan formation during sedimentary period are analyzed by synthesizing the factors of stratigraphic thickness, sandstone thickness, mudstone thickness, sand content and coal seam thickness, and the regularity of coal accumulation in sequence framework is discussed. Four kinds of sedimentary facies, including meandering river, braided river, delta and lake, were identified and 23 microfacies of 10 subfacies were identified in Yanan formation, and the characteristics of different sedimentary facies were summarized. According to the principle of sequence stratigraphy, the Yan'an formation in the study area is divided into 6 sequences and 15 system tracts, and the sequence stratigraphic pattern of the study area is established. Sequence development is mainly controlled by such factors as tectonic rise and fall, lake level change, paleoclimate, sediment flux and accommodation space, etc. The paleogeographic characteristics of different sedimentary periods in Yan'an formation were systematically studied in system tracts. The sedimentary period of Yan'an formation in the study area underwent four stages: initial filling of lakes, lake expansion and lake atrophy. The sedimentary facies model of Yan'an formation has been established. This paper summarizes the coal accumulation law of the main coal seams in Yan'an formation, and establishes four coal accumulation models: Houhe Man swamp, Huwan peat marsh, delta front distributary interbay peat swamp and delta plain distributary depression peat swamp. During coal enrichment period, it is the largest water entry system tract, and the best coal rich zone is west and northwest of the mine field.
【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】：P618.11

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