东营凹陷东辛地区沙河街组一段两类储层结构成因

Two Type of Reservoir Structure Formation of Member 1 of Paleogene Shahejie Formation in Dongxin Area,Dongying Sag

东辛地区沙河街组一段发育大量湖相碳酸盐岩与碎屑岩。利用东营凹陷东辛地区沙一段的岩石薄片、铸体薄片鉴定、压汞与岩石物性测试等方法及分析测试数据,结合岩心观察,从储层的岩性特征、物性特征、储层的空间类型等方面对各类岩石的物性、孔隙类型进行了分析,精细表征了沙一段储层微观特征及主控因素。研究表明,东辛地区沙一段碳酸盐岩和碎屑岩均为研究区的有利储层,储层物性碳酸盐岩优于碎屑岩,储层物性的优劣表现为鲕粒灰岩>生屑灰岩>含砾粗砂岩>粉细砂岩;碎屑岩内主要发育原生粒间孔、粒间溶孔及微裂缝等储集空间类型,碳酸盐岩以发育生物体腔孔、粒内溶孔、粒间溶孔、铸模孔为主;沙一段储层具有沉积作用主控、成岩作用改造、断裂体系促进储层物性的特点,受下伏深层烃源岩生烃转化的影响,沙一段深层储集岩体更容易受溶蚀作用影响,形成含油性良好的储层。

Lacustrine carbonates and clastic rocks are extensively developed in Member 1 of Shahejie For- mation in Dongxin area. On the basis of rock thin sections, casting thin sections, mercury penetration, da- ta analysis and core observations, we have comprehensively analysed pore types of reservoir including res- ervoir lithology, property and space type to reveal the microscopic features and controlling factors of reser- voir in Member 1 of Shahejie Formation. The results show that： 1） Lacustrine carbonates and clastic rocks are both the favorable reservoirs and carbonate reservoir physical property is better than that of clastic rocks, oolitic limestone〉bioclastic limestone〉conglomeratic coarse sandstone〉fine siltstone; 2） The original intergranular pore, intergranular dissolved pore and microfracture are dominant reservoir space types in the clastic rocks, while the carbonates develop intragranular pore（organism cavity）, intragranular dissolved pore, intergranular dissolved pore and mold pore; 3） The reservoirs of Member 1 of Shahejie Formation are characterized by being controlled by deposition,transformed by diagenesis and improved by fracture system. Due to the hydrocarbon generation of underlying source rocks, Member 1 of Shahejie For mation is more easily affected by the dissolution to form excellent oil reservoirs.