【作者】 黄成刚；

【导师】 黄思静；

【作者基本信息】 成都理工大学 ， 矿物学、岩石学、矿床学， 2004， 硕士

【摘要】 近年来，对胜利油田济阳坳陷桩西、埕岛地区下古生界古潜山的勘探取得了丰硕成果。随着勘探程度的不断加大，也需要对其潜山储集层的研究不断深入与之相适应，本文着重从地球化学的角度对桩西、埕岛地区下古生界古潜山储层的发育机制进行了研究和探讨。 岩石学研究表明，桩西、埕岛地区下古生界古潜山储层的岩石类型有碳酸盐岩、粘土岩、碎屑岩、以及少量蒸发岩，其中碳酸盐岩是该区下古生界古潜山储层最主要的岩石类型，为一种稳定地台型海相沉积环境的产物。 通过对桩西、埕岛地区下古生界碳酸盐岩的地球化学特征研究，表明在岩石的各种结构组分中，洞或脉中的方解石充填物具有显著较高的⁸⁷Sr／⁸⁶Sr比值，较低的δ¹³C、δ¹⁸O和较高的Mn含量，其所经历的重要岩溶作用是大气淡水成岩作用，发生的时间为表生成岩阶段。 通过本区白云岩的研究发现：已有的白云岩样品的岩石学特征没有显示出如示底构造、渗滤沙、新月型胶结物和重力胶结物等大气淡水作用的特征；在白云石MgCO₃mol百分数和白云石Sr含量的投点图中，无论是准同生成因的泥—微晶白云岩，还是粉—细晶（或中晶，或细晶以上的不等晶）的成岩白云岩，均投在海水线的附近；白云岩（或基质）的⁸⁷Sr/⁸⁶Sr比值显著低于与孔洞或脉中充填的亮晶方解石，且与海水值十分接近，δ¹³C和δ¹⁸O值显著高于孔洞或脉中充填的亮晶方解石，也偏向于海水值；Mn含量则显著低于孔洞或脉中充填的亮晶方解石。因此，我们认为桩西、埕岛地区寒武—奥陶系白云岩主要有两种不同的成因类型，即准同生白云岩和成岩白云岩，并且成岩白云岩是在埋藏成岩过程中，在粒间孔隙水中由交代作用形成的。白云岩储集岩主要分布在成岩白云岩中，因而成岩白云岩的形成机制便直接与储层孔隙的形成机制相关。成岩白云岩孔隙的形成机制有:l)岩石的原生孔隙度是成岩白云岩储层形成的必要条件。一部分成岩白云岩仍具有残余粒屑结构，其原岩可能主要为各种类型的粒屑灰岩，这类岩石通常具有较高的初始孔隙度（原生孔隙度），这是以后形成成岩白云岩储层孔隙的重要基础条件。2)在白云石化过程中岩石粒屑的收缩作用可以形成白云岩储层孔隙。 我国东部深大断裂对桩西、埋岛地区寒武一奥陶系碳酸盐岩的储层孔隙影响很小，可能发生在喜山期的岩溶作用（深部流体带来的岩溶作用）也是十分有限的。更多还原

【Abstract】 In the last few years, we had obtained plenteous harvests on the exploration of lower Palaeozoic burial hills in the regions of Zhuangxi and Chengdao, Jiyang depression. With the enhancing of the exploration degree, it needs more deep research on its reservoirs to adapt to it. This thesis emphasizes to proceed the study on the mechanism of formation of the reservoirs of lower Palaeozoic burial hills in the regions of Zhuangxi and Chengdao from the angle of geochemistry.The research of petrology reveal rock types of the regions mainly include carbonate rock, claystone, siltstone, breccia and a few of evaporite rock. Among of them, carbonate rock is the primary type of them, it is the product of stable platform facies of marine.We study the geochemical characteristic of carbonate rock of lower Palaeozoic burial hills in the regions of Zhuangxi and Chengdao and find that the calcite fillings in cave or vein have high value of 87Sr/86Sr, low value of 13C and 18O and high Mn content among of different structural components. So it has been exposed to be dissolved by meteoric water on supcrgene diagenetic stage.We find that the petrology characteristic of all the samples have no characteristic of meteoric water such as geopetal structure, infiltrative sand, (uniform cement and gravitational cement on base of the research of the dolomite in the regions. On the dot diagram of combination of MgCO3(mol%) and Sr, the dot are all close to the line of seawater whether they are microlite-crystalline penecontemporaneous dolostone or diagenetic dolostone of various crystals. The 87Sr/86Sr value of dolostone or matrix is less than the one of sparry calcite in cave or vein, and close to the value of seawater. The 5 ’ C and 8 ’ O values of dolostone or matrix is greater than the ones of sparry calcite in cave or vein, but whose content of Mn is less than the ones of sparry calcite obviously. So we can draw a conclusion that the dolostone of C-O stratum in the regions of Zhuangxi and Chengdao has primarily two genesis types, they are penecontemporaneous dolostone and diagenetic dolostone. The diagenetic dolostone is formed by replacement in intergranular pore water on the course of burial diagenesis. The reservoir of dolomite is mainly distributed in diagenetic dolostone. So the formation mechanism of diagenetic dolostone have directly relation with that ofthe reservoir pore. The formation mechanism of the pore of diagenetic dolostone includes: 1) The primary porosity is essential condition for the formation of dolostone reservoir. A lot of diagenetic dolostones have remainder granulation structure, and the native rock of it may be various intraclast limestone. This type of rock usually has high primary porosity. The high primary porosity is the important base of forming the pore of dolostone reservoir. 2) The contraction action of granulations can form the pore of dolostone reservoir in the course of dolomitization.Huge deep fractures in the east of China have a little influence on the pore of carbonatite reservoir of €-O stratum in the regions of Zhuangxi and Chengdao. The karstification which probably happened at Xishan tectogenesis period is also very limited.更多还原