金湖凹陷西斜坡阜宁组灰岩段混积储层特征

金湖凹陷灰岩段为灰岩与砂岩混层沉积，灰岩储层与砂岩储层特征差异较大。综合运用岩芯、物性分析以及 铸体薄片资料分析灰岩段储层特征和储层控制因素。灰岩段由3 个沉积韵律组成，每个韵律的下部为泥岩或泥灰岩， 上部为生物碎屑灰岩或砂岩。生物碎屑灰岩平均孔隙度12.7%，平均渗透率为21 mD，属低孔低渗型储层。灰岩储集 空间以粒内孔为主，粒间溶孔和铸模孔为辅，裂缝多被方解石全充填或半充填。砂岩储层平均孔隙度16.36%，平均渗 透率为47.11 mD，属中孔中渗型储层，砂岩储层以粒间孔为主。灰岩储层铸体薄片资料显示储层孔隙和喉道分选均较 差，非均质性强，而砂岩储层孔隙和喉道分选性好，较均一。储层物性和非均质性明显受到沉积环境、米级旋回和成岩 作用等因素的影响。平面上，构造高部位生物碎屑灰岩发育，储层物性好，非均质性弱，纵向上，米级旋回上部生物碎 屑灰岩发育，储层物性也较好。

Mixing Reservoir Characteristic of Limestone Member in West Slope of Jinhu Depression

Limestone member is the important oil production layer，but its reservoir is of strong heterogeneity. Based on cores，physical property test and casting slice data，reservoir feature and controlling factors can be analyzed. Three deposition cycles comprise limestone member. The lower part of every cycle consists of mudstone and marlstone；the upper part consists of biolithite limestone and muddy biolithite limestone. With average porosity of biolithite limestone of 12.7%，and average permeability of 21 mD，the reservoir falls into low porosity and low permeability type. The relationship between porosity and permeability is poor，so secondary pores develop well，with little primary pores. Reservoir space mainly consists of dissolving pore distributed inter-grains，and dissolving pore distributed inner-grains and mold pore are little. Cracks are filled or half filled by calcite. Based on casting slice data，pore and throat of reservoir is of poor sorting and strong heterogeneity. Physical property and heterogeneity of reservoir are controlled by sedimentary facies，M level cycle and diagensis. Horizontally，biolithite limestone developed well on high structural point，and physical property is good and heterogeneity is poor. Vertically，biolithite limestone developed well on upper M level cycle，with good physical property.