Hydrodynamics mechanism of viscoelastic fluids displacing residual oil droplets in micro pores

Key words:  viscoelastic fluids  polymer flooding  micro pores  residual oil  Wiesenberger number

Abstract:

In order to analyze the microscopic stress field acting on residual oil droplets in micro pores, calculate its deformation, and explore the hydrodynamic mechanism of viscoelastic fluids displacing oil droplets, the viscoelastic fluid flow equations in micro pores were established by choosing the upper convected Maxwell constitutive equation. The numerical solutions of the flow field were obtained by volume control and alternate direction implicit methods. The velocity field and microscopic stress field, the forces acting on residual oil droplets, the deformations of residual oil droplets by various viscoelastic displacing fluids were calculated and analyzed. The results demonstrate that both the normal stress and horizontal force acting on the residual oil droplets by viscoelastic fluids are much larger than those of inelastic fluid. The distribution of normal stress changes abruptly. Under the condition of the same pressure gradient, the ratio of the horizontal forces acting on the residual oil droplets by different displacing fluids which are water, the power law fluid and viscoelastic fluid with Wesson Borg number of 0.3 is about 1∶8∶20. The viscoelastic fluids cause the residual oil droplet to deform significantly, and the flooding is better.