古交杨庄勘探区晋祠组—太原组层序格架古地理演化及聚煤规律

发布时间：2018-04-05 15:15

本文选题：杨庄勘探区　切入点：晋祠组-太原组　出处：《中国矿业大学》2016年硕士论文

【摘要】：杨庄勘探区位于山西古交市南端的草庄头村周围,估算资源量12.29亿吨,下二叠统晋祠组-太原组为主要的含煤地层之一。而随着对杨庄井田勘探程度的不断加深,迫切需要对杨庄井田开展全面的煤炭赋存规律研究工作。本文以经典层序地层学、岩石学、沉积学、煤地质学等学科的理论和方法为指导,再结合杨庄勘探区野外40余口钻孔资料、测井资料的分析,以及Y2-10井和Y3-6井的野外精心编录,对杨庄勘探区晋祠组-太原组沉积相,层序的划分、古地理的展布以及煤层的聚集规律等进行了研究。研究表明,杨庄勘探区晋祠组-太原组时期为一陆表海浅水三角洲-碳酸盐岩台地-障壁岛-泻湖-潮坪体系,并进一步划分为7个亚相和9个微相。其次,通过层序界面的识别,将晋祠组-太原组分为4个三级层序,8个体系域,并建立了研究区层序地层格架。SQ1时期主要发育一套海侵体系域和高位体系域,海侵体系域以碳酸盐岩台地和泻湖为主,东部普遍发育厚度不大的吴家峪灰岩,海水自东北面而来;高位体系域发育潮坪沉积,未见煤层;SQ2时期也发育海侵体系域和高位体系域,沉积相以三角洲平原-泻湖-潮坪为主,泥炭沼泽广泛发育,形成全区厚度大、分布广泛的8#煤和9#煤,在SQ1末期华北地台发生跷跷板运动,地层由南高北低变为北高南低,海水来自东南方;SQ3时期,海水几次侵入后退,形成庙沟和毛儿沟灰岩,灰岩中含大量的蜓化石。高位体系域以潮坪相为主,发育全区局部可采的7#煤层;SQ4时期海水最后一次从南面入侵,形成全区广泛分布的斜道灰岩,L4灰岩为质地纯净的生物碎屑灰岩沉积,是整个华北地区晚古生代最大海侵的产物,高位体系域发育一套分流河道微相和分流间洼地微相为主的沉积,并在三角洲平原上发育泥炭沼泽,形成局部发育的6#煤层。海水自此全面撤出山西全境。8#煤层发育于SQ2海侵体系域内,煤层分布面积广,厚度大、层位稳定,结构简单至复杂,厚度变化的总体规律为西北厚,东南薄,三角洲相比潮坪相更适合沉积厚煤层。煤厚等值线图与硫分等值线图出现惊人的相似性,说明海平面变化对聚煤演化起着重要的控制作用。9#煤层发育于海侵体系域中,除局部地区未见煤外,全区稳定分布,煤层呈向东开口的半弧形展布,总体厚度变化的趋势是向东向北厚度逐渐增厚。地形古地理和海平面共同控制9#煤煤厚的变化,而在未见煤地段发育分流河道砂岩,应是在后生冲刷作用下导致煤层在此处尖灭。
[Abstract]:Yangzhuang exploration area is located around Caozhuangtou Village in the southern tip of Gujiao City Shanxi Province. The estimated amount of resources is 1.229 billion tons and the Lower Permian Jinci formation-Taiyuan formation is one of the main coal-bearing strata.With the deepening of the exploration degree of Yangzhuang mine field, it is urgent to carry out a comprehensive study of coal occurrence law in Yangzhuang mine field.Guided by the theories and methods of classical sequence stratigraphy, petrology, sedimentology and coal geology, this paper combines the field data of more than 40 boreholes in Yangzhuang exploration area, the analysis of logging data, and the detailed cataloguing of Y2-10 well and Y3-6 well in the field.The sedimentary facies, sequence division, paleogeography distribution and coalbed accumulation of Jinci formation and Taiyuan formation in Yangzhuang exploration area were studied.The results show that the Jinci formation to Taiyuan formation in Yangzhuang exploration area is a shallow water deltaic carbonate platform barrier island lagoon tidal flat system and is further divided into 7 subfacies and 9 microfacies.Secondly, through the identification of sequence interface, the Jinci formation-Taiyuan formation is divided into 4 third order sequences and 8 system tracts, and a set of transgressive system tracts and high system tracts are mainly developed in the period of sequence stratigraphy framework. SQ1 in the study area.Transgressive system tracts are dominated by carbonate platforms and lagoons, and Wujiayu limestone is generally developed in the east of China.Transgressive system tracts and highstand system tracts were also developed in the period of SQ2. The sedimentary facies were mainly delta plain, lagoon and tidal flat, peat swamp was widely developed, and formed large thickness and widely distributed 8# coal and 9# coal in the whole area.Seesaw movement occurred in the North China platform at the end of SQ1, the strata changed from high in the south to low in the north to low in the north and south. The sea water came from the period of SQ3 in the southeast of China. The sea water intruded and retreated several times, forming Miaogou and Maogou limestone, which contained a large number of fly fossils.The highstand system tract is dominated by tidal flat facies and developed the last intrusion of seawater from the south in SQ4, a locally recoverable coal seam in the whole area, resulting in a wide distribution of sloping limestone and L4 limestone deposits of pure bioclastic limestone in the whole area.It is the product of the largest transgression of the late Paleozoic in the whole North China. A set of distributary channel microfacies and interdistributary depression microfacies are developed in the upper system tract, and peat swamps are developed on the delta plain, forming locally developed 6 # coal seam.Since then, the sea water has completely withdrawn from the whole area of Shanxi Province. The coal seam has been developed in the SQ2 transgression system region. The coal seam has a wide distribution area, a large thickness, a stable horizon, a simple and complex structure, and the overall law of thickness variation is thick in the northwest and thin in the southeast.The delta is more suitable for thick seams than tidal flat facies.The remarkable similarity between the contour map of coal thickness and that of sulfur shows that the sea level change plays an important controlling role in the evolution of coal accumulation. The coal seam is developed in the transgressive system tract, with the exception of no coal in the local area, the stable distribution of the whole area.The coal seam has a semi-arc distribution with an orifice to the east, and the thickness of the coal seams tends to increase gradually from the east to the north.Topography, paleogeography and sea level control the variation of coal thickness; however, distributary channel sandstone is developed in the unseen coal area, which should be caused by epigenetic scouring to cause coal seams to be destroyed here.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P618.11;P531

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