摘要
白云岩的结构不仅在白云岩成因研究方面具有重要意义还对白云岩储集空间的发育具有控制作用。在大量岩心、薄片以及扫描电镜分析的基础上,结合物性测试资料,针对塔里木盆地寒武系—奥陶系不同结构类型的白云岩在储集性能方面的差异进行了研究,并探讨了岩石微观结构对储集空间发育的控制作用。结果表明:①白云岩的结构特征与储层物性具有明显相关性,细晶、平面—自形白云岩(多孔的、砂糖状白云岩)孔渗性最好,其次为粉—细晶、平面—半自形白云岩,中—粗晶、曲面—它形白云岩以及保留原始结构的白云岩物性最差;②白云岩的结构类型同样影响着白云岩储层的储集空间及储层类型,随着白云石晶体结构由平面—自形向曲面—它形的转化,其储层类型也由以晶间孔为主的孔隙型储层转变为溶蚀孔洞型或裂缝型储层;③侵蚀性流体对储层的改造方式也受白云岩结构的制约,导致研究区白云岩地层中往往不发育大型洞穴储集体,而是以呈层状分布的孔隙型或针状溶孔型储层为主。
The study of dolomite texture not only indicates the origin of the dolomites but controls the quali ty of dolomite reservoirs significantly. The main objectives of this paper are to investigate the differences of the dolomite reservoirs with distinct textures and the relationship between dolomite texture and reservoir development of the Cambrian-Ordovician carbonate rocks in central Tarim Basin, based on observation of core, thin-section and SEM,combined with the analyses of petrophysical properties. The results show that. （1）Dolomite texture can be used to predict the reservoir quality due to the strong interdependency between petrophysical properties of the reservoir and dolomite texture, the reservoir qulity of the fine-crystalline. Planar-e（euhedral） dolomite is the best of all the dolomite reservoirs,and the very-fine to fine crystalline planar-s（subhedral） dolomite reservoir is mediate, but the medium to coarse crystalline,non-planar-a（anhedral） dolomite and precursor lithologic fabric preserved dolomite are poor in porostiy; （2） Dolomite texture also affects porosity type. With the shape of dolomite crystal changing from planar-e to non-planar-a, the porosity of dolomite reservoir transforms intercrystalline pore to vug and fracture porosity; （3）The formation and modification process of dolomite reservoir are controlled by dolomite texture, resulting in the shortage of cave porosity and abundance of thin-bedded,porous intervals with intercrystalline/vug porosity in the dolomite reservoirs.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第3期341-350,470,共11页
Natural Gas Geoscience
