Study On Different Factors Affect Oil Displacement Of The Polymer System

As the mature of polymer flooding technology and perfectness of various accessorymeasures,Polymer flooding technique is widely used in Daqing Oilfield.Polymer floodingtechnique remarkably decrease moisture content and improve crude oil recovery in fieldapplication.This paper studies the effect of polymer flooding system and influencing factor inClass II Reservoirs of Daqing oilfield for Improving the utilization rate of polymer solution.It could be determined the concentration and the injection rate of different molecularweight（s1.9×107and2.5×107）polymer solution Through flow experiment of polymer floodingsystem.It studies the concentration of polymer solution and the effect of alternate times andvarious slug combinations on oil displacement efficiency in the scheme of constant velocityinjection.In the scheme of Constant pressure injection,it studies the effect of the concentrationof polymer solution,injection pressure,different injection mode and various slug combinationson oil displacement efficiency.At last,it verifies the result of Constant pressure injection andconstant velocity injection in the natural core.The results show that1.9×107and2.5×107molecular weights the concentration ofpolymer solution is2075mg/L and1500mg/L,this two kinds of The viscosity of polymersolution is78.9mPa·s（45℃）.Whether constant velocity injection or constant pressureinjection scheme,low molecular weight and high concentration of chemical flooding is higherwhen keeping constant viscosity of two different polymer solution though lowing polymermolecular weight and improving the concentration of polymer solution.It can improve oildisplacement efficiency when increasing the concentration of polymer solution and molecularweight unchanged. Constant velocity alternating Injection polymer flooding scheme is betterthan these two kinds of monolithic polymer slug flooding scheme, and the recovery rateincreased with increasing of the number of alternating Injection.