Abstract: After long-term water-flooding extraction, primary integrated reservoir gradually evolves into secondary bottom water reservoir, and its remaining oil can be categorized as the weakly movable remaining oil in the upper-middle part, the by-passed movable remaining oil in the lower middle part, and the residual oil after water flooding in the high water flooded area. The tapping potential of such oil reservoir is exploited with ASP flooding. Based on the production data, the ASP flooding history is divided into three stages, namely the pre-effective stage, sustained effective stage, and the post-effective stage, and the time span of sustained effective stage is calculated. With quantified displacement characteristic curve, displacement capacities of wells in the sustained effective stage are calculated. Also, engineering, geographical, and chemical factors that affect the displacement effect are analyzed. The results show that the development characteristics of APS flooding in secondary bottom water reservoir differ considerably from those of conventional bottom water reservoirs, while the engineering and geographical factors have similar effects on these two reservoirs. The polymer components in oil displacement agents play an important part in oil-water seepage throughout the development history.

Key words: secondary bottom water reservoir, ASP flooding, displacement characteristic curve, chemical plugging, remaining oil, water-out