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碳酸盐胶结物是酒东坳陷下白垩统砂岩内一种重要的自生矿物,其对深部储层储层质量有着重要影响。本文通过薄片观察、扫描电镜、能谱分析及碳氧同位素分析,认为碳酸盐胶结物主要为铁方解石、白云石和铁白云石,并且以后者为主,其分布具有不均一性且分带性明显。碳酸盐胶结物均为成岩作用后期产生,形成该矿物所需的物质主要来源于泥岩的黏土矿物转化和有机质热演化,还有一部分钙来源于斜长石的蚀变。碳酸盐胶结物的溶蚀溶解是深部低渗透储层中发育较为优质储层的重要原因,该溶蚀溶解必须存在流体运移的通道,另外,碳酸胶结物含量也对储层质量有所影响,当碳酸盐含量大于5%时,储层孔隙度随碳酸盐胶结物含量增加而降低,而当其含量小于5%时,储层孔隙度与碳酸盐胶结物含量之间没有明显对应关系。
Carbonate cement is an important authigenic mineral in the Lower Cretaceous sandstone in the JiuDin Depression, which has an important influence on reservoir quality in deep reservoirs. In this paper, the observation of thin film, scanning electron microscopy, energy spectrum analysis and carbon and oxygen isotope analysis, that carbonate cement mainly calcite, dolomite and iron dolomite, and the latter mainly the distribution of heterogeneity and zonation obvious. Carbonate cements are all produced in the late stage of diagenesis. The materials needed to form this mineral mainly come from clay mineral transformation of mudstone and thermal evolution of organic matter, and some calcium comes from alteration of plagioclase. The dissolution and dissolution of carbonate cements is an important reason for the development of higher quality reservoirs in deep low permeability reservoirs. The dissolution and dissolution must exist channels for fluid migration. In addition, the content of cemented carbonate also affects the reservoir quality, When the carbonate content is more than 5%, the porosity of the reservoir decreases with the increase of the carbonate cement content. When the content is less than 5%, there is no obvious correspondence between the reservoir porosity and the carbonate cement content relationship.