川中高石梯～磨溪地区震旦系灯影组热液作用及其对储层的影响

发布时间：2018-02-27 18:18

本文关键词： 灯影组热液作用鞍状白云石储层特征　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文主要以地层学、岩石学、矿物学、地球化学、储层地质学和国内外最新相关研究进展为理论指导,以钻测井资料和地震资料为基础,对高石梯～磨溪地区震旦系灯影组白云岩的热液作用进行较深入的研究。从岩石学特征和地球化学特征上提供了热液白云岩的存在依据,分析了热液作用的形成条件及形成模式,并阐述了热液作用对储集空间的改造及灯影组白云岩储层的形成演化。热液作用的岩石学研究表明,研究区发育有以热液白云岩为母岩的密西西比河谷型矿化作用形成的方铅矿和闪锌矿及其共生的热液附属矿物：鞍状白云石、长石、萤石、石英、黄铁矿以及方解石,它们以裂缝和孔洞充填或者以交代的方式出现在热液白云岩中,其中鞍状白云石被普遍认为是热液作用的指示者。热液作用的地球化学研究表明,研究区灯影组热液白云岩与早期白云岩和海水相比,δ180同位素值偏小,是由于温度效应使重的18O进入到流体中,轻16O进入到白云石中；87Sr/86Sr同位素比值偏大,是由于热液白云石化作用时,在埋藏条件下有放射性锶87Sr进入到热液白云岩中,这些放射性87Sr,来自硅质碎屑物,或来自岩浆作用或变质作用的残余流体；微量元素Mn和Fe值偏大,是由于热液白云石化作用是在埋藏环境中发生的,为还原环境,热液流体中的Mn和Fe处于低价状态,可以进入到白云石晶格中。稀土元素显示Ce和Eu的正异常,与海水的稀土元素模式相反,可能是由于热液流体的作用造成的。结合研究区构造特征、演化背景及地层特征,分析了热液作用形成条件,包括由于兴凯地裂运动造成的拉张性的大地构造背景、下伏碎屑岩层的热液储库和上覆沉积层的覆盖和封堵,并建立了热液作用形成模式图。此外,通过岩心和岩石薄片的观察,详细阐明了热液作用改造的储集空间特征,包括晶间孔和晶间溶孔、角砾孔、热液溶蚀孔洞、裂缝。分析了研究区的主要成岩作用,认为建设性的成岩作用包括重结晶和新生变形作用、岩溶作用、热液溶蚀作用。最后,探讨了储层的形成与演化过程,建立了灯影组储层孔隙演化模式。
[Abstract]:This paper is mainly guided by stratigraphy, petrology, mineralogy, geochemistry, reservoir geology and the latest related research progress at home and abroad, and based on drilling log data and seismic data. The hydrothermal action of dolomite of the Dengying formation of Sinian system in Gaoshiti ~ Moxi area is studied in depth. The petrological and geochemical characteristics of the dolomite are provided as a basis for the existence of hydrothermal dolomite. The forming conditions and forming modes of hydrothermal action are analyzed, and the transformation of reservoir space by hydrothermal action and the formation and evolution of dolomite reservoir in Dengying formation are expounded. The petrological study of hydrothermal action shows that galena and sphalerite formed by the Mississippi Valley mineralization with hydrothermal dolomite as parent rock and their associated hydrothermal subsidiary minerals: saddle dolomite, feldspar, fluorite, Quartz, pyrite and calcite, which appear in hydrothermal dolomite in the form of fractures and pores or in metasomatism, of which saddle dolomite is generally regarded as an indicator of hydrothermal action. The geochemical study of hydrothermal process shows that the 未 180 isotope value of hydrothermal dolomite in Dengying formation is smaller than that of early dolomite and seawater, which is due to the temperature effect that makes heavy 18O into the fluid. The relatively large isotope ratio of 87s / 86Sr into dolomite is due to the presence of radioactive strontium 87Sr into hydrothermal dolomite under burial conditions, which are derived from siliceous debris. Or residual fluid from magmatism or metamorphism, the trace element mn and Fe are higher because hydrothermal dolomitization occurs in a buried environment, and mn and Fe in hydrothermal fluid are in a low-priced state in a reductive environment. The rare earth elements show positive anomalies of ce and EU, contrary to the REE model in seawater, which may be caused by the action of hydrothermal fluids. Based on the structural characteristics, evolution background and stratigraphic characteristics of the study area, the forming conditions of hydrothermal process, including the extensional tectonic background caused by the Xingkai tectonic movement, are analyzed. The hydrothermal reservoir and the overlying deposit of the underlying clastic rock are covered and sealed, and the model diagram of hydrothermal action is established. In addition, through the observation of cores and thin pieces of rock, the reservoir space characteristics of hydrothermal transformation are expounded in detail, including intergranular pore and intergranular solution pore, breccia pore, hydrothermal solution hole and fracture. The main diagenesis of the study area is analyzed. Constructive diagenesis includes recrystallization and new deformation, karstification and hydrothermal dissolution. Finally, the formation and evolution process of reservoir is discussed, and the pore evolution model of Dengying formation is established.
【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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