鄂尔多斯盆地胡尖山地区上三叠统延长组长4+5—长6段储层特征及其与石油运聚关系

Reservoir Characteristics of Member 4+5 & 6 of Yangchang Formation from Upper Triassic in Hujianshan Area,Ordos Basin and Their Relationship with Oil Accumulation

从储集层地质发育特征、岩石组成与成岩作用、物性与孔隙类型等方面,分析了鄂尔多斯盆地胡尖山地区上三叠统延长组长6—长4+5段砂岩储集层的特殊性,对储集层特征与石油聚集的关系进行了探讨。砂体主要发育于三角洲前缘亚相中的水下分流河道微相中,具有较强的非均质性。砂岩以长石岩屑细砂岩为主,成岩作用较强,物性总体较低,多为低孔低渗—致密储集层,有效孔隙类型主要为粒间孔、溶蚀孔隙和晶间孔。石油在不同物性的储集层中均有聚集,含水层多具有较高的孔隙度和渗透率,所以,储集层本身特征对石油的聚集不起决定性作用,还必须要有一定厚度的物性较好的储集层、输导通道与油源的良好配置才可能形成油藏。

From the reservoir geological characteristics, rock composition and diagenesis, physical properties,pore types and so on,this paper analyzes the particularity of sandstone reservoirs in the member 6 to the member 4＋5 of the upper Triassic Yanehang Formation from the Hujianshan area of Ordos basin,and discusses the reservoir characteristics and their relationship with oil accumulation. The sand body with strong heterogeneity develops in submarine distrihutary channel of delta front. The sandstones are mainly feldspathic lithic fine sandstone with strong diagenesis and low physical property values as a whole. Most of the reservoirs are low porosity and low permeability-tight and the effective pore types are mainly intergranular pore, dissolution pore and intracrystalline pore. Oil accumulates in the reservoir layers with different physical properties and many aquifers have high porosity and permeability. So reservoir characteristics itself can not afford a decisive role in the petroleum gathering. There must have a good assemblage of higher physical property value reservoir,conduct pathway and oil surce can form oil pool.