【作者】 黄擎宇；

【导师】 张哨楠；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 塔中地区奥陶系发育多种类型的碳酸盐岩储层,其均具有非均质性强、影响因素多、勘探难度大等特点,为此,论文以沉积岩石学、储层地质学等为理论指导,综合钻(测)井、岩心、薄片等资料,开展了塔中地区奥陶系碳酸盐岩储层成因机理和主控因素的研究。在吸收前人研究成果的基础上,充分利用研究区多口钻井的取心资料,对岩心及薄片进行详细观察,总结了塔中地区奥陶系碳酸盐岩的岩石学特征和成岩作用特点,并建立了相应的成岩序列作为储层成因研究的依据。通过对良里塔格组岩相、成岩作用、储集空间及物性特征的分析,认为该组的储层主要与同生岩溶和表生岩溶有关。同生岩溶作用受沉积相控制明显;表生岩溶与不整合面发育特征关系密切,尤其是加里东中期二幕岩溶对良里塔格组储层的发育具有重要影响。塔中南、北坡折带是良里塔格组储层的有利发育部位:优势相带、同生岩溶、表生岩溶的共同作用使该区储层明显优于其他区域,其中又以北坡即塔中I号断裂带附近储层储集条件最好。鹰山组储层同生岩溶不发育,主要受表生和埋藏溶蚀作用控制。鹰山组顶部发育的多个不整合面代表了其在地质历史过程中曾受多期表生岩溶的影响,因此该组岩溶作用范围广、纵向分带性明显;埋藏溶蚀作用对下奥陶统白云岩储层具有重要影响,尤其是与二叠纪岩浆活动期间,侵蚀性热液流体对白云岩层进行改造,形成了新的溶蚀孔洞,对于寻找内幕型白云岩储层非常有利。塔中地区碳酸盐岩储层受多种因素的控制,特别是沉积相带、岩溶作用及白云石化作用对储层的发育影响深远。沉积相带是储层发育的物质基础,不同的沉积相带,由于沉积物的组成不同、古地理位置各异,从而导致其储集特征存在着明显的差异性。岩溶作用是塔中碳酸盐岩储层形成的关键,研究区主要的溶蚀作用包括同生岩溶、表生岩溶和埋藏岩溶:同生岩溶分布局限,主要发育于良里塔格组中;表生岩溶作用期次多、影响范围广,不同层位均有分布;与热液作用有关的埋藏溶蚀主要受断裂系统控制,对储层改造明显,但层位不稳定。白云石化作用对于下奥陶统白云岩储层的形成演化具有重要意义,白云石结构类型、白云石化程度共同控制了白云岩储层的发育,浅埋藏期形成的直面、自形-半自形、粉-细晶白云岩以及成岩晚期的热液白云岩储集性能最好。更多还原

【Abstract】 Various types of carbonate reservoir developed in Tazhong region,but many previous studies indicate that the reservoir properties are of the characteristics of strong heterogeneities,multiple influencing factors and petroleum exploration is characterized by large difficulty.Aiming at the shortage,this paper deals with the genetic mechanism of Ordovician carbonate reservoir in Tazhong region and its key controlling factors by integrating drilling and logging date analysis,cores observation,thin section identification,and so on.In addition,all these study are under the theoretical guidance of sedimentary petrology,reservoir geology,etc.Based on absorbing the studied results of former geologists, cores and thin section are observed detailedly by fully applying coring data in interesting area.As a result, this paper has generalized petrology characteristic and diagenesis of Ordovician carbonate rock in Tazhong region.And corresponding diagenesis sequence is also established,which could be used as a criterion for discussing the origin of reservoir.With the analysis of lithofacies,diagenesis,reservoir space and physical property of Lianglitage formation in interesting area,it is considered that the reservoir of Lianglitage formation is chiefly related to syndepositional karstification and epigenetic karstification. Diagenesis analysis approves that the syndepositional karstification is controlled obviously by sedimentary facies.And epigenetic karstification is closely related to unconformity,especially influenced by the second episode karstification of Middle Caledonian.According to all the study above,it show that slope break belts in the southern and northern of Tazhong region are the favorable position for the reservoir in Lianglitage formation.In conclusion,under the combined action of prevailing face belt,syndepositional karstification and epigenic karstification,the reservior in these zones become more favorable than others.Moreover,the reservior in the northern slope break belt(i.e. the zone close to the Tazhong-ⅠFault) is better between these two slope break belts.The syndepositional karstification was not development in reservoir of Yingshan formation, it was mainly controlled by epigenetic karstification and burial karstification. Much unconformity developed on the top of Yingshan formation interprets it was influenced by epigenetic karst in the long history, so the karstification in Yingshan formation influenced a large area and has a significantly longitudinal zonation. Burial dissolution has important influence for the dolomite reservoir of lower Ordovician, especially in the period of Permian magmatism, hydrothermal fluid transformate dolomite and formate more solution pore, this result is better for discover the inner buried dolomite reservoir.There are several factors controlling the carbonate reservoir of Tazhong area, such as sedimentary facies, karstification and dolomitization. Sedimentary facies are the material basis for reservoir development. Differences in reservoir characteristics is caused by the different sedimentary facies, sediment composition and ancient geographical location. Variety of dissolution including syndepositional,epigenetic and buried karstification is key to the formation of carbonate reservoirs in the study area. Syndepositional karst with restricted distribution, mainly developed in the Lianglitage formation. Multi-period and large range epigenetic karstifications are distributed in different strata; Buried karstification which relate with hydrothermal fluids is mainly affected by the fault system. This karstification plays an important role on the reservoir reconstruction, however, its distribution is not controlled by strata. Dolomitization is vital to the formation and evolution of the dolomite reservoir in the Lower Ordovician. The structure type of dolomite and the degree of dolomitization control dolomite reservoir development jointly. The dolomite with best reservoir performance is distributed on the planar-e(s), finely crystalline dolomite formed in the shallow burial period and hydrothermal dolomite formed in the deep burial period.更多还原