There is the further potential tapping for the main productive layers in block B, and this is owing to a certain amount of untapped remaining oil after water flooding and polymer flooding. The research focus on the remaining oil distribution and characteristics of post⁃polymer flooding, by means of numerical simulation and the data analysis of sealing coring wells and log interpretation of water flooded layers, which shows the remaining oil horizontally concentrates in fluid diversion line with 2.35 percent higher than main streamline oil saturation and is vertically distributed in layer PⅠ2 and PⅠ3. Therefore, the research of streamline variation to enhance oil recovery has been performed to analyze the influence from different ones on EOR, which indicates that the well pattern infilling in fluid diversion line is optimum. According to the geological characteristics and current well patterns, three kinds of well adjustment patterns have been designed on basis of previous research. The streamline variation by well pattern infilling has been adopted through contrastive analysis which can enhance EOR by predict 1.26 percent by water flooding and 5.17 percent more with high concentration polymer flooding.