Abstract Carbonate cementation is one of the significant tightness factors in Chang 6 reservoir of the western Jiyuan (WJY) area. Based on the observation of core and thin sections, connecting-well profile analysis as well as carbon and oxygen isotope analysis, it is found that ferrocalcite is the main carbonate cements in the Chang 6 reservoir of the WJY area. The single sand body controls the development of carbonate cements macroscopically. Both carbonate cements and calcite veins hold similar diagenetic conditions: the dissolution of plagioclase is the main calcium source and the de-acidification of organic acids is the main carbon source. The diagenetic stage is identified as the mesogenetic A stage. The sedimentary environment is of low salinity. Accordingly, the development model of carbonate cementation in Chang 6 reservoir is summarized into three types: “eggshell pattern,” “cutting pattern,” and “favorable reservoir pattern.” The development degree of carbonate cementation affects the physical properties of reservoir.

中文翻译：

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致密油储层碳酸盐胶结成因模式——以鄂尔多斯盆地西部济源地区上三叠统延长组长6油层为例

摘要 碳酸盐胶结作用是济源西部长6油藏显着的致密性因素之一。通过岩心和薄片观察、连通井剖面分析以及碳氧同位素分析，发现铁方解石是WJY地区长6储层的主要碳酸盐胶结物。单一砂体宏观控制碳酸盐胶结物的发育。碳酸盐胶结物和方解石脉都具有相似的成岩条件：斜长石的溶解是主要的钙源，有机酸的脱酸是主要的碳源。成岩阶段被确定为中生 A 阶段。沉积环境为低盐度。因此，长6油藏碳酸盐岩胶结发育模式概括为“蛋壳型”、“切割型”和“有利储集型”三种类型。碳酸盐胶结发育程度影响储层物性。