玉北地区下奥陶统蓬莱坝组储层特征与主控因素

发布时间：2018-02-20 18:31

  本文关键词： 玉北地区 沉积相 储层特征 成岩作用 主控因素　出处：《中国地质大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：本文以沉积学、储层地质学、地球化学为理论基础,通过对岩心、薄片、扫描电镜、阴极发光等方面的分析,对塔里木盆地玉北地区蓬莱坝组的沉积相、储层特征、成岩作用等方面进行了研究,取得了如下成果:(1)蓬莱坝组沉积期研究区为局限台地相,可进一步分为泻湖、潮坪、台内滩亚相,玉北5井岩心出现的渗流豆、碴状层、帐篷构造等暴露标志表明蓬莱坝组曾经短期暴露,也证明了鹰山组与蓬莱坝组之间的T78界面为不整合面。(2)白云岩类为蓬莱坝组最主要的岩石类型,根据岩石结构特征与特殊构造可分为细晶白云岩、中晶白云岩、粗晶白云岩、(残余)颗粒白云岩、藻纹层白云岩,其中以中晶白云岩的储集性能最佳。晶间孔、晶间溶孔、溶蚀孔洞以及构造裂缝是玉北地区最主要的储集空间。泥晶化、溶蚀、压溶、重结晶、破裂、白云石化作用为研究区建设性的成岩作用;胶结、压实、充填、热液作用等对储层发育不利,为破坏性成岩作用。(3)通过对蓬莱坝组溶孔方解石充填物、缝洞白云石充填物、裂缝方解石充填物的碳氧同位素分析发现,14组数据中有9件样品的碳同位素值低于早奥陶世的最低值-1.5‰;在11件缝洞方解石充填物样品中,有10件的δ18O介于-10.1‰~-14.4‰,平均为-12.9‰,显著低于早奥陶世正常海相碳酸盐岩的值,同时也低于鞍形白云石的氧同位素组成,高负特征明显,表明大气淡水是参与成岩作用的重要流体。(4)优质储层受沉积相、成岩作用、构造运动共同控制。局限台地内的台内滩相为白云岩储层的发育提供了较好的物质基础。与T78界面相关的大气淡水作用是优质储层形成的关键因素,后期白云石化作用有利于孔隙的保存。此外,和田古隆起的发育演化为大气淡水淋虑提供了一定的条件,构造运动所形成的断裂及构造裂缝,增加了水与碳酸盐岩的接触面积,增加了溶蚀范围,是良好的流体渗滤通道。
[Abstract]:Based on the theory of sedimentology, reservoir geology and geochemistry, the sedimentary facies and reservoir characteristics of Penglai formation in Yubei area, Tarim Basin, are studied by analyzing the core, thin slice, scanning electron microscope and catholuminescence. The diagenesis has been studied, and the following results have been obtained: (1) the sedimentary period of Penglai Dam formation is a restricted platform facies, which can be further divided into lagoon, tidal flat, subfacies of beach within the platform, percolation of the core of well Yubei 5, and ballasted bed. The T78 interface between Yingshan formation and Penglai formation is unconformable face. 2) dolomite is the main rock type of Penglai dam formation. According to the characteristics of rock structure and special structure, it can be divided into fine grain dolomite, medium grain dolomite, coarse grain dolomite grain dolomite, algal dolomitic dolomite, in which mesocrystalline dolomite has the best reservoir performance. The voids and structural fractures are the most important reservoir space in Yubei area. Mud crystallization, dissolution, pressure solution, recrystallization, rupture and dolomitization are constructive diagenesis, cementation, compaction, filling, etc. Hydrothermal process is unfavorable to reservoir development, which is destructive diagenesis. The carbon and oxygen isotopic analysis of fractured calcite fillers shows that 9 of the 14 samples have lower carbon isotopic values than the lowest values of early Ordovician (-1.5 鈥，

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