The Microcosmic Mechanism Of Viscoelastic Polymer Flooding Heavy Oil

For some offshore heavy oil field, due to the constraints such as that offshore platform use fixednumber of year, a growing number of offshore oil field start with the method of polymer flooding ininitial state of production, in order to improve the recovery efficiency of heavy oil in a short time, theflow in the reservior pore is two phase flow of polymer solution-heavy oil system. Also for some ofthe heavy oil field of the land, the oil field grew into the latter period of reservoir development; alarge amount of residual oil has not yet been out of the ground. The oil fields often adopt the methodof polymer injection to improve recovery efficiency. Therefore, it is very necessary to study the flowlaw of polymer solution flooding of heavy oil and residual oil flooding of heavy oil in the reservoirpore.Based on the viscoelastic fluid finite element numerical simulation software Polyflow, the paperinvolves three aspects: the single-phase flow of polymer solution in simplified channel of thereservoir, two-phase flow of polymer solution flooding heavy oil, and polymer solution floodingresidual oil of heavy oil. For polymer single-phase flow, the influences have been studied, which iscaused by the viscolasticity of polymer, pressure gradient, characteristics of simplified pore channel.The change of the polymer micro swept area is explained, through analysis to the change of stressfield in flow process. In polymer-heavy oil two phase flow, the influences have been studied, whichis caused by the viscolasticity of polymer, pressure gradient, the yield stress of heavy oil. At the sametime, the area that the viscoelasticity of polymer play a role is studied in the real complex pore, microoil displacement efficiency is calculated in the real reservoir pore. In the numerical simulation ofpolymer flooding residual oil, the influences have been studied, which is caused by the viscolasticityof polymer, pressure gradient, the yield stress of heavy oil. It is proved that heavy residual oil startedto transport, when the pressure gradient is greater than the start-up pressure gradient of heavy oil.Through the study of this article, it has laid a solid foundation for the future to numerically simulatethe micro polymer flooding of heavy oil flowing law.