Study on start-up of residual oil for different grades of water flooding zones at ultra-high water-cut stage

Abstract

At present stage, most of the oil reservoirs in China have entered the ultra-high water-cut period, and the heterogeneity is serious. The water flooding effects in different zones of the reservoirs are obviously different. The overall reservoir recovery degree is low, and there is still a large amount of remaining oil remaining in all grades of water flooding zones. This paper mainly carried out the relevant physical model experiment of the remaining oil in the ultra-high water-cut period, and simulated the recovery of the remaining oil under different subsequent flooding conditions after entering the ultra-high water-bath period of different grades of water flooding zones. The start-up law of the remaining oil in the different grades of water flooding zones was observed and analyzed. According to the experimental results, it can be seen that in the period of ultra-high water cut, the strong water flooded zone has a greater exploitation potential than the extreme water washing zone and the weak water flushed zone. Therefore, the focus of developing in the ultra-high water-cut stage should be placed on the strong water flooded zone, and the water flooding after adjusting the profile by injecting jelly can effectively improve the recovery rate of the strong water flooded zone.