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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 structure of the dolomite is of great importance not only in dolomite genetic studies but also in the control of dolomite reservoir development. Based on the analysis of a large number of cores, thin slices and scanning electron microscopy, the differences in reservoir properties of different types of dolostones of Cambrian-Ordovician series in the Tarim Basin have been studied based on the data of physical properties. Structure controls the development of reservoir space. The results show that: (1) The structural characteristics of dolomite have obvious correlation with the reservoir physical properties. The fine-grained, planar-automorphic dolomite (porous and granulated dolomite) has the best porosity and permeability followed by powder-fine grain, - Semi-automorphic dolomite, medium-coarse grain, curved surface-dolomite with its shape and the dolomite with the original structure have the poorest physical properties. (2) The structure type of dolomite also influences the reservoir space and reservoir type of dolomite reservoir , With the dolomite crystal structure from planar to self-directed to curved surface - its shape conversion, the reservoir type is also changed from intergranular pore-dominant reservoir to dissolved pore-type or fractured reservoir. ③Erosion The modification of the reservoir by the fluid is also restricted by the structure of the dolomite. As a result, large-scale cave reservoirs are often not developed in the dolomite strata of the study area. Instead, the pore-type or needle-like dissolved pore reservoirs distributed in layers are the Lord.