Effect of Elastic Behavior of HPAM Solutions on Displacement Efficiency Under Mixed Wettability Conditions

Abstract

Abstract In this paper, the oil displacement efficiencies of viscous-elastic HPAM solutions and viscous glycerin solutions are studied by flooding at visual microscopic glass models. Also, the effect and mechanism of the viscous-elastic behavior of HPAM solutions and glycerin solution on the displacement of residual oil films under mixed wettability conditions and residual oil at blind-end are studied, the relationship between the elastic behavior of HPAM and oil displacement efficiencies is given. The results of rheological characteristic measurement indicate that both the viscosity and the first normal stress differential (N1) of HPAM solutions increase with the increase in concentration, HPAM solutions show strong viscous-elastic characteristics under high concentration conditions. The results of microscopic oil displacement experiments indicate the displacement efficiencies of HPAM solution flooding and glycerin solution flooding gradually increase with the increase in the viscous-elastic behavior of HPAM solutions and the viscosity of glycerin solutions. However, for HPAM solution flooding, the displacement efficiency is always higher and residual oil saturation lower than that of glycerin at the same viscosity and same capillary number and at the same oil saturation after water flooding.