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扶杨油层是松辽盆地致密油勘探重要的目的层,碳酸盐胶结作用是造成储层致密的重要原因,揭示碳酸盐胶结物特征对认识和评价扶杨油层致密储层具有重要意义。本文通过岩心精细描述、岩石薄片鉴定和孔渗分析,详细介绍了碳酸盐胶结物的宏观和微观特征。研究表明:扶杨油层孔隙度主体为6%~18%,小于12%的样品占60%以上;渗透率小于1×10~(-3)μm~2的样品占70%以上,碳酸盐胶结物是扶杨油层主要的胶结物类型,碳酸盐含量与孔隙度和渗透率总体呈负相关关系。方解石主要以微晶和亮晶为主,微晶方解石主要以孤立状分布,亮晶方解石呈连晶状胶结。砂岩底部物性差,碳酸盐含量高,中上部物性变好,碳酸盐含量低。扶杨油层多以砂泥互层或薄砂厚泥组合为特征,砂岩顶底泥岩较发育,砂泥互层结构有利于泥岩中粘土矿物转化过程中分离出来的钙、铁、钾等离子进入毗邻的砂岩中,并在砂岩内富集和沉淀,从而形成碳酸盐胶结物。
Fuyang oil layer is an important target of tight oil exploration in Songliao Basin. Carbonate cementation is an important reason for the formation of tight reservoirs. Revealing the characteristics of carbonate cements is of great significance for understanding and evaluating the tight reservoirs in Fuyang oil layer. In this paper, macroscopic and microscopic features of carbonate cements are introduced in detail by fine description of cores, identification of rock slices and pore permeability analysis. The results show that the main porosity of Fuyang reservoir is 6% ~ 18%, while the samples with less than 12% account for more than 60%. The samples with permeability less than 1 × 10 ~ (-3) μm ~ 2 account for more than 70% Cement is the main type of cements in Fuyang oil layer. Carbonate content is negatively correlated with porosity and permeability. Calcite is mainly dominated by crystallites and spherules. Microcrystalline calcite is mainly isolated in an isolated form, and calcite is crystallized. Sandstone bottom physical properties, high carbonate content, the upper part of the physical properties become better, low carbonate content. Most of the oil reservoirs in Fuyang are characterized by sand-mud interbeds or thin-grained thick mud combinations, top-bottom mudstones in sandstone are well developed, and interlayer structure of sand and mud is favorable to the separation of calcium, iron and potassium ions from the clay minerals in mudstone during the conversion process Of the sandstone and enriched and precipitated within the sandstone to form a carbonate cement.