| This paper studies systematically about the feasibility application of the visco-elastic polymer flooding and Alkaline/Surfactant/Polymer(ASP) flooding under the conditions of high-temperature reservoir.In addition,the function of polymer visco-elastic and the displacement mechanism has been lucubrated.On the basis of studying a large number of domestic and foreign theoretical literature about polymer flooding and ASP flooding,we have studied the polymer thermal stability,the polymer rheological and viscoelastic effection on enhancing oil recovery under the conditions of high temperature,the three components of ASP flooding displacement mechanism,as well as their synergistic effect.Based on the results, polymer flooding and ASP flooding has been optimized and screened out.This dissertation is divided into the following sections,and will be descripted briefly:1,long-term thermal stability and visco-elasticity of polymer.Under the conditions of high-temperature,the stability of the polymer displacement fluid played a very important role. Two kinds of stabilizers were evaluated.It was first proposed that a low concentration of polyhydroxy compound stabilizer can enhance the chemical stability of the polymer solution, and can effectively control the viscosity grow rate.The results of physical simulation show that injection velocity on the polymer solution can increase flexibility,thereby it can enhance oil displacement efficiency.When the injection velocity is higher than 0.5mL/min,the system showed a higher viscoelasticity.Under the same viscosity conditions,the high viscoelastic polymer flooding oil displacement experiments can reach a relatively higher efficiency.2,Study of polymer theology.We examined the impact of polymer concentration on the viscoelasticity and viscoelasticity on the role of oil displacement efficiency.The results showed that it was only concentration reaching a certain degree that it shows significant viscoelasticity.3,By three different elastic fluids but in the same viscosity flow experiments,we obtained that elasticity has a positive effect on enhancing oil recovery,while the viscosity is less.4,Physical flow experiments.We studied different concentrations polymer,different size and different penetration effect on the improving the efficiency,as well as changes in visco-elasticity caused by hydrolysis effected on enhancing oil recovery.It is obtained from experiments that the suitable polymer concentration is 2000 mg / L,and the slug size is 0.4-0.5PV. 5,Formulation of ASP flooding system.It showed that the composite system can achieve the minimum interfacial tension when the surface-active agent and alkali concentration was in a certain range.The viscosity was controlled mainly by the concentration of polymer,while surfactant concentration does not affect the viscosity,but it is the most important factor of effecting the interfacial tension system.We measured the static adsorption capacity of the three components.The results proved that the polymer and alkali has obvious protective effect on the of agents adsorption.6,A series of porous media flow experiments by ASP system have been done.The results showed that interfacial tension is the major factor of substantially increasing EOR,especially when the interfacial tension reached 10-4 magnitude system,the effect is particularly evident. It is the first time to be proposed that different water-oil viscosity ratio has the impact on oil displacement efficiency.It is also obtained that with the water-oil viscosity ratio increased, the enhanced oil recovery rate is increasing.Meanwhile,the rate of increase slowed down when the viscosity ratio is more than 8.4.As the result,the range of the polymer concentration should be 1000～1500mg / L.Considering the absorption as well as economic and other factors,the system should be adoped as 0.25%QY-3 +1500 mg / L polymer +0.5% Na2CO3.As it can maintain a high viscosity,the system has a good effect on enhanced oil recovery of 22%.
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