【摘要】 以芦草沟组为研究对象,采用物理模拟和数值模拟方法,综合铸体薄片、高压压汞和微米CT等分析测试,分析致密储层含油饱和度增长过程,揭示致密油聚集过程及其主控因素。结果表明:致密储层含油饱和度增长模式分3种,相渗曲线和最终含油饱和度存在较大差异;致密油聚集过程及渗流特征主要受充注压力和孔隙结构控制,充注压力是含油饱和度增长的必要条件,孔隙结构是导致含油饱和度增长过程存在差异的主要因素,其中孔喉半径和配位数控制作用明显;孔喉半径增大,水相相对渗透率减小,油相相对渗透率和有效渗透率均增大;配位数增大,水相相对渗透率增大,油相相对渗透率减小,但油相有效渗透率呈指数增大,石油渗流能力增强,储层含油饱和度增长速度呈逐渐增大的趋势,最终含油饱和度也逐渐增大。更多还原

【Abstract】 Tight oil in Lucaogou Formation is treated as the target. In combination with thin section, high-pressure mercury injection and micro-CT, physical simulation and numerical simulation are conducted to analyze growth process of oil saturation of tight reservoirs, aiming to demonstrate the accumulation processes and their controlling factors.Growth pattern of oil saturation is divided into three types, which show significant differences in the oil-water relative permeability curve and final oil saturation.The accumulation process and flow characteristics are dominantly influenced by the injection pressure and pore structure of tight reservoirs. The injection pressure is a prerequisite for the increase of oil saturation, and pore structure is the main factor to control the growth pattern of oil saturation. Variations in pore throat radius and coordination number play a significant controlling role in the growth pattern of oil saturation. As pore throat radius increases, water relative permeability decreases, whereas oil relative permeability and effective permeability increase. Increase of coordination number results in the increase of water relative permeability and decrease of oil relative permeability. However, oil effective permeability magnifies exponentially and oil flowing capability is strengthened. As a result, growth rate of oil saturation and final oil saturation increase gradually.更多还原