鄂尔多斯盆地西部奥陶系马家沟组四段沉积相研究

发布时间：2018-02-09 16:33

本文关键词： 鄂尔多斯盆地西部马四段沉积相沉积模式　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文针对当前鄂尔多斯西部地区马家沟组四段碳酸盐岩地层划分、沉积微相和沉积相分布规律等方面的研究现状和所存在的问题,以地层学、碳酸盐岩岩石学、构造地质学以及沉积学理论为指导,运用野外和室内、宏观和微观相结合的方法,以野外剖面和岩芯精细观察描述、常规显微薄片观察及鉴定为基础,结合碳氧同位素地化分析数据,对地层格架、沉积相划分、相标志、纵向沉积组合序列、平面分布规律进行了深入研究。在区域地质背景、构造作用史等地质特征分析基础上,进行了岩性特征、测井曲线特征和古生物综合分析,认为研究区地层横向上东西向呈现出中间厚两边薄的趋势,由南向北地层厚度具有逐渐增厚的趋势。平面上研究区以棋探1-鄂19-余探1井为界,西部地层厚度平面分布规律性明显,自东向西地层厚度具有明显增厚趋势。东部马四段地层厚度平面上以定边地区为高值区,逐渐向四周变薄；系统总结了研究区马家沟组马四段沉积特征,将其划分为碳酸盐岩台地与碳酸盐岩缓坡两种沉积相,并可进一步细分为6个亚相带和若干个微相。横向上,自西向东为由海槽-深缓坡-浅缓坡组成的碳酸盐岩缓坡相过渡为由浅滩-台坪亚相组成的碳酸盐岩台地相。说明研究区沉积环境为自西向东水体逐渐变浅,水体能量逐渐增强,中央古隆起以东再度减弱。马四时研究区承袭了马三时的古地貌,马四时研究区水体有所加深,因此沉积物岩性以灰质白云岩以及灰岩为主。随着海侵过程进一步扩大,海水的入侵方向与早期入侵方向一致,台坪面积具有明显缩小的变化趋势,沉积物类型以灰色白云岩为主,局部夹泥岩和含泥含云泥晶灰岩。其外主要为台地沉积,沉积物类型以深灰色厚层-块状泥晶灰岩、颗粒灰岩以及细晶一粉晶白云岩为主。研究区马四段平面上沉积相变化规律性明显,自西向东方向依次发育海槽、深缓坡、浅缓坡和浅滩、台地。在上述研究的基础上建立了研究区沉积相模式图。
[Abstract]:At present, the western region Ordos four member of Majiagou Formation carbonate strata, sedimentary microfacies and sedimentary facies research status and other aspects of the distribution and the problems in carbonate stratigraphy, petrology, structural geology and sedimentology, using field and laboratory, the combination of macroscopic and microscopic methods, described by field section and the core of fine observation, conventional microscope observation and identification based on analysis of data combined with the carbon and oxygen isotope, the stratigraphic framework, sedimentary facies, facies, vertical sedimentary sequence, plane distribution laws were studied.
In the analysis of regional geological background, tectonic history and geological features on the basis of comprehensive analysis of lithology, logging curves and paleontology, the study area that strata horizontal East-West appears on both sides of the thin middle thick, from south to north with strata thickness gradually thickening trend. The plane in the study area of chess 1- Hubei 19- exploration over 1 well as Western circles, formation thickness plane distribution regularity, from east to West stratigraphic thickness has obvious trend. The eastern section of the horse four thickened stratum thickness on the plane in Dingbian area high value area around to gradually thinning;
The four section summarized the sedimentary features of Majiagou Formation in the study area, which is divided into carbonate ramp carbonate platform and two kinds of sedimentary facies, and can be further divided into 6 subfacies and several microfacies. Horizontally, from west to east by the carbonate ramp trough - deep ramp - shallow ramp the phase transition consists of carbonate platform for Taiwan Shoal flat sub facies composed of phase. The sedimentary environment of the study area is from the west to the East water gradually becomes shallow, the water energy gradually increased, the central uplift of the East once again weakened. Ma Sishi study area inherited the ancient landform Ma three, Ma Sishi has water in the study area therefore, to deepen, sediment lithology calcareous dolomite and limestone. With the transgression process to further expand the direction of seawater intrusion and intrusion early direction, Tai Ping area change tendency is significantly reduced, sediment types in gray Dolomite, local mudstone and mud containing limestone. Its main Unni as platform sediments, sediment types in dark gray thick bedded and massive micritic limestone, grain limestone and fine crystal dolomite. The study area four plane sedimentary facies variation regularity is obvious, from the west to the to the East are developed trough, deep ramp, shallow ramp and shallow tableland. Sedimentary facies model was established on the map on the basis of the above research.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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