Physical Simulation On Influence Factors Of Polymer Flooding Effect

In the middle and late period of polymer flooding,the distribution of remaining oil is dispersed and the difficulty grows for stabling the oil production.The mismatch between flooding system or injection method and reservoir causes the phenomenon of profile reverse.Considering those question in oil field,physical simulation of polymer flooding is done for recognizing the influence of permeability,oil saturation and flooding system on polymer flooding effect.The difference of percolation mechanism,flow characteristics and displacement efficiency between three injection methods is also studied.The new experimental model with three parallel plate core mode composed of an injection and a production wells is applied as well as a new experimental method with stability in constant pressure and constant flow rate.All those new methods make the results of physical simulation closer to the actual site in aspects of progress and theory.The results show that the displacement efficiency increase at first but reduce slightly later with the viscosity of polymer grows in heterogeneous reservoirs.The oil saturation affects the fluid mobility in different layers during the high water cut stage,thus influencing the injection profile of different layers.The effects of three injection methods including single polymer slug,viscosity reduce continuous polymer slugs,viscosity grows continuous polymer slugs is given and evaluated.The mechanism of employing remaining oil and flow characteristics of different injection methods is analyzing and contracting.It shows that the injection method with viscosity reduce continuous polymer slugs is the best for laboratory experiment with higher the pressure gradient in middle and low permeability reservoirs is higher,bigger swept volume and later time for the beginning of profile reversal.