The Research On The Mechanism Of EOR By Viscoelastic Two-component Displacement System With No Anlika

Based on rheology, surface chemistry, fluid dynamics and fluid mechanics in porous medium theory, aimed on the enhanced oil recovery, the problems after ASP compound flooding that clay is dispersed and migrated, alkali incrustation is formed, permeability is reduced can be caused by the displacement liquid with alkali, and alkali also reduces viscoelasticity of polymer solution making sweep efficiency reduced. Using the new amphoteric surfactant that can attain ultralow interfacial tension with oil at the condition with no-alkali, following works are researched.The interfacial characteristic and the rheological property between polymer solution, surfactant solution, polymer-surfactant solution and oil are studied. The research results show that concentration, molecular weight, temperature and salinity have the effect on the interfacial characteristic of chemical solution. The concentration variety of mono-system has the effect on the interfacial characteristic between mono-system and oil. The interaction of polymer, surfactant and alkali has the obvious effect on interfacial characteristic and viscosity and the influence and effect mechanism are related with polymer, surfactant and alkali concentration on the binary system.A great deal of work is reviewed including the status of effect of interfacial behavior between polymer and oil upon displacement. An integral mechanical energy balance equation for the system is established. The relation between interfacial dimensionless axial displacement speed, dimensionless flow rate dimensionless and the relation of dimensionless average flow rate and dimensionless interfacial tension, interfacial viscosities and wetting angle between polymer and oil. We study the effect of in dimensionless interfacial tension, interfacial viscosities and wetting angle between polymer and oil upon diaplacing velocity in the undulating tube mode is analyzed. The conclusions are gained, when the direction of interfacial curvature is adverse with the direction of polymer flooding, the dimensionless interfacial tension and interfacial viscosities between polymer and oil all make dimensionless interfacial axial displacement speed, dimensionless flow rate and dimensionless average flow rate decrease, the larger its value is, the more larger dimensionless interfacial axial displacement speed, dimensionless flow rate and dimensionless average flow rate decrease. When the direction of interfacial curvature is same with the direction of polymer flooding, the dimensionless interfacial axial displacement speed, dimensionless flow rate and dimensionless average flow rate all increase with the accretion of dimensionless interfacial tension.The displacement oil experiments were finished in artificial core,the displacement oil effects of surfactant flooding and SP flooding after water flooding are analyzed with that of after polymer flooding. The probability of enhancing oil recovery of surfactant flooding and SP flooding are analyzed quantitatively after polymer flooding. The results of investigation indicate that oil recovery can be enhanced by surfactant flooding and SP flooding further after polymer flooding. But the effect of enhancing oil recovery is not obvious especially by surfactant flooding after polymer flooding, the effect of enhancing oil recovery is more obvious by SP flooding after polymer flooding.The displacement oil experiments of microscopic model were progressed, the seepage flow process of different interfacial tension surfactant flooding and different viscoelasticity and interfacial tension SP flooding is acquired after polymer flooding in the dead-end model and artificial homogeneous model. The distribution of remaining oil are analyzed, startup and moving mechanism of kinds of residual oil are analyzed. The probability of enhancing oil recovery is verified further by surfactant flooding and SP flooding after polymer flooding. The results of investigation indicate that oil recovery can be enhanced further by surfactant flooding and SP flooding after polymer flooding. The advancing value of oil recovery and final oil recovery are enhanced with interfacial tension decreasing in surfactant flooding after polymer flooding. The advancing value of oil recovery and final oil recovery are enhanced with viscoelasticity of polymer raising and interfacial tension decreasing in SP flooding after polymer flooding.