Well test analysis on pressure of viscoelastic polymer solution with variable rheological parameters*

Abstract

According to the behavior that the polymer solution has both the characteristics of viscosity and elastic properties, the transient flow mathe- matical model considered the viscoelasticity of the polymer solution has been established. The model, in which the variation of the rheological parameters during the seepage flow has been also taken into consideration, has been solved using finite-difference method. The type curves have been plotted. The influence of some properties of polymer solution including the viscocity, the elastic properties and the rheological parameters has been analyzed. Compared with the curves of the power-law fluid, it is shown that the pressure derivative curve considering the elasticity of the polymer solution upwarps less at the radial flow regime. Besides, it will come down as the variation of the rheological parameters, which is quite different from the case regarding them as constants. Therefore, in well test analysis on pressure of polymer solution, it’s necessary to consider the elasticity and the variation of the rheological parameters.