The Quantitative Describe Of Contribution Of The Elasticity And Injection Parameters Optimization Of Polymer Lfooding Based On Numerical Simulation

Polymer flooding development of main oil layers of Daqing Oilfield was gradually cometo a close and quite a lot of them were turned to subsequent water flooding. So it is quitenecessary to develop Class II reservoirs in order to realize the output connection for polymerflooding. The polymer flooding development project will influence the effect of polymerflooding and reduce economic benefits seriously, if it is not scientific enough. Recently, theexperience of polymer flooding to Class II reservoirs development is deficient. So theinjection parameter optimization of polymer flooding is quite significantly to guide theproduction of polymer flooding to Class II reservoirs.In this paper，ECLIPSE numerical simulation software is used to build up a conceptualmodel which has Five-spot well pattern. Together with the physical parameters in Class IIreservoirs, the influence which is made by physical parameters and injection parameters isanalyzed. The distribution of velocity field and viscosity field of water flooding and polymerflooding from different development stages can be calculated and the contribution of viscosityand elasticity to displacement efficiency can be quantitative described. Taking economicbenefits and recovery as target functions, the injection parameters which are suitable to the oillayers which have different permeability can be chosen. The results showed that: The velocityfield distrbution difference of water flooding is shaper than that of polymer flooding. Seepagevelocity at the injection well bottom is about as120times as that at central area and viscosityat the central area is as3to5times as that at bottom. With the increasing of molecularweight，concentration of the polymer solutions and the amount of the Polymer which isinjected into the oil layers, the ratio which elasticity is contributed to displacement efficiencyis generally enhanced. The influence which is caused by the changing of injection-productionwell spacing is quite limited. When the polymer injection amount is0.57PV and the polymermolecular weight is2300×10~4, the ratio which elasticity is contributed to displacementefficiency is40%. If the molecular weight is3500×10~4, the ratio becomes45%. There is aeconomic benefit balance point between polymer injection amount and production for samespecies of polymer solution. The injection parameters which are suitable for the oil layerswhich permeabilities are800×10-3μm~2,400×10-3μm~2and200×10-3μm~2are given in this paper.