Field application of profile control throughout polymer flooding

The technique of profile control throughout polymer flooding can prevent the breakthrough of polymer and post-water flooding and improve the drive effects of polymer.The profile control in block-wide was made in V Block before polymer flooding and inⅠ_5+Ⅱ_(1-3) Block before post-water flooding.The radius of profile control ranges from 50 meters to 80 meters,and the amount of profile control agent in a well is in the range 3692 m~3 to 15300 m~3.The ratio of profile controlled wells to polymer-injected wells is over 75%.The field application showed that the injection pressure increased,and the apparent injecting index reduced.The pro- duced polymer concentration was obviously reduced from 170mg/L to 31mg/L after two years of polymer flooding.The natural de- cline ratio of oil production in other blocks without profile control is 28.4%,but the oil production of blocks with block-wide profile control increased in first year of post-water flooding.