Effect of Elastic Behavior of HPAM Solutions on Displacement Efficiency UnderMixed Wettability Conditions

摘要

In this paper, the oil displacement efficiencies of viscouselasticrnHPAM solutions and viscous glycerin solutions arernstudied by flooding at visual microscopic glass models. Also,rnthe effect and mechanism of the viscous-elastic behavior ofrnHPAM solutions and glycerin solution on the displacement ofrnresidual oil films under mixed wettability conditions andrnresidual oil at blind-end are studied, the relationship betweenrnthe elastic behavior of HPAM and oil displacementrnefficiencies is given. The results of rheological characteristicrnmeasurement indicate that both the viscosity and the firstrnnormal stress differential (N_1) of HPAM solutions increasernwith the increase in concentration, HPAM solutions showrnstrong viscous-elastic characteristics under high concentrationrnconditions. The results of microscopic oil displacementrnexperiments indicate the displacement efficiencies of HPAMrnsolution flooding and glycerin solution flooding graduallyrnincrease with the increase in the viscous-elastic behavior ofrnHPAM solutions and the viscosity of glycerin solutions.rnHowever, for HPAM solution flooding, the displacementrnefficiency is always higher and residual oil saturation lowerrnthan that of glycerin at the same viscosity and same capillaryrnnumber and at the same oil saturation after water flooding.