High Concentration Of Polymer Flooding In Enhanced Oil Recovery Methods Of Experimental Study

Petroleum is a kind of irreproducible resources, and it's also an important national economy vital. With the exploitation of oil reserves, especially when the water cut of reserves is high, both the economy index and technique index will get worse. The water cut of oil well increases, the production decreases, and the infrastructure investment and cost increase. How to exploit the residual oil in the stratum efficiently after water flooding, which accounts for 60-70% reserves in place, is a main task of petroleum engineering experts the entire world.Polymer flooding and ASP flooding has improved oil recovery a lot in Daqing oil field. At the same time, there are still some problems, such as the increasing of injection pressure of polymer and transfusion resistance. This aggravates the imbalance between injection and recovery. In ASP flooding, the existence of alkali not only need to increase the concentration of polymer solution but also decreases the visco-elastic characteristic of polymer, which decreases the oil recovery of polymer flooding. And also because the existence of alkali, high viscosity w/o emulsion begin forming which not only influents off-take potential of oil well but also increases the difficulty of emulsion breaking. And the crust of alkali influents oil well a lot.Usually the injection pressure increases with the increasing of concentration and molecular weight of polymer, which limits the concentration of injection polymer. When the dose level of polymer is settled, the change of injection volume and concentration do not increase oil recovery obviously. While the result of lab research shows that the increasing of oil recovery of high concentration and high molecular weight polymer flooding can reach or over that of ASP flooding. And there is no theory about this at present. The aim of this paper is to study how injection time, different assemblage of polymer slug and concentration of polymer solution influence the oil recovery in high concentration and high molecular weight polymer flooding. If we optimize the experiment scheme in some ways, then we can improve the oil recovery efficiently, and decrease the cost, and contribute to the realization of exploitation the residual oil after water flooding cheaply and efficiently.