Low permeability reservoir is one of main objectives of oil and gas exploration all around the world. It is proved that the pore structure is a key factor in the nature of low - permeability reservoirs during exploration and development. Microscopic characteristics of the low permeability reservoir were studied with the integration of data such as thin section analysis, molded thin sections, scanning electron microscope, intrusive mercury, constantspeed mercury intrusion etc. Pore structure were divided into three types according to the type of penetration. The remaining oil was divided into seven types with the analysis of fluorescence microscopic thin section. The relationship between microscopic structure and residual oil was studied. It was concluded that the types of microscopic residual oil in low permeability reservoirs were mainly the absorption inter particle , thin film on pore surface and cluster. The formation of remaining oil in type one pore structure was major related to fragmentation of clay and snapoff, and in type three pore structure, the formation of remaining oil was major related to detour flow.%低渗透储层是目前国内外油气勘探的主要对象之一.勘探、开发实践证明,孔隙结构特征是影响低渗储层性质的关键因素.综合镜下普通薄片、铸体薄片观察、普通压汞、恒速压汞等多种资料研究了低渗储层的微观孔喉分布特征,并根据渗透率将孔隙结构类型分为三类,结合荧光薄片分析将水洗后微观剩余油分为七类,研究了微观剩余油与微观孔隙结构的关系,认为低渗透储层微观剩余油主要是粒问吸附状、孔表薄膜状和簇状,一类孔隙结构中剩余油的形成主要和碎裂泥化和卡断作用有关,三类孔隙结构中剩余油的形成主要和绕流作用有关.
展开▼
