Transient Pressure Analysis Of Viscoelastic Polymer Solution

Polymer flooding is an important tertiary oil recovery technology. Presently the major oil regions of most domestic oil fields have been entered a large high water cut development stage. With the increasing difficulty in stabilizing the output, some field tests and industrial field tests of polymer flooding have been conducted, and the technical and economic benefits have been proved to be significant. In recent years, a lot of domestic and foreign experts have done a large number of researches on flow characteristics of the polymer solution in porous media and the influence on the flooding effects. However, in most dynamic analysis on pressure of polymer flooding, the polymer solution is always assumed as Newtonian fluid or pseudoplastic fluid, its elasticity is ignored. Therefore, in this paper, to study the dynamic analysis on pressure of viscoelastic polymer solution, the following work is carried out:The rheology and viscoelasticity of the polymer solution has been analyzed. The radial transient flow mathematical model of of a homogeneous reservoir with viscoelastic polymer solution has been established and solved. The type curves have been plotted. The influence of the relaxation time, the power-law index and the consistency coefficient of polymer solution on the characteristics of the type curve has been analyzed.The radial transient flow mathematical model of a compound reservoir with viscoelastic polymer solution and Newtonian-fluid flow has been built. The type curves have been plotted. The influence of the relaxation time, the power-law index and the consistency coefficient of polymer solution on the characteristics of the type curve has been analyzed.Besides, the influence of theAs well as the two phase mathematical model of viscoelastic polymer solution and gas, the two phase mathematical model of viscoelastic polymer solution and oil has been set up. In these models, besides the changing of the concentration, the influence of the viscoelasticity to the effective viscosity and the residual oil saturation has been taken into consideration, too. The type curves of the iniection well have been plotted. The influence of some properties of polymer solution on the characteristics of the type curve has been analyzed.Finally, some actual examples of the transient pressure analysis of polymer solution are given.