Study On The Oil Displacement Mechanism And The Seepage Law Of Different Polymer Surfactant

As a very promising chemical flooding agent,polymer surfactant has already been concerned by domestic and overseas oilfields and scientific research institutions.As a potential tertiary oil recovery technology after polymer flooding,polymer surfactant flooding has achieved some success experience in domestic and overseas oilfields.Although some scientific research institutions have begun to study the polymer surfactant as a new type of oil displacement agent,there is lack of enough understanding of many aspects of polymer surfactant,such as physical and chemical properties,seepage law and so on.And they still can not give a clear explanation to some problems appeared in the field tests.Therefore,a deeper study on the performance,the oil displacement mechanism and the macroscopic seepage law of polymer surfactant needs to be done.Through laboratory experiments,we used the micro lithography glass models to study the oil displacement mechanism of three polymer surfactant in this paper,and we also made a comparison.Based on the study and comparison of oil displacement mechanism experiments of three polymer surfactant,we got the following results: Huading I type polymer surfactant had the biggest stage swept area in three polymer surfactant,Haibo BI type polymer surfactant had the best displacement efficiency,and Lianhua III type polymer surfactant was not prominent in stage swept area and displacement efficiency,which indicated that Lianhua III type polymer surfactant was not suitable for the experimental conditions in this paper.We also studied the physical and chemical properties of polymer surfactant,such as stability,shearing resistance,salt resistance and so on.And we studied the injectivity of polymer surfactant on the basis of above study,determined the optimal injection concentration and the optimal slug size.The optimal injection concentration of three polymer surfactant all is 1000mg/L,and the optimal slug size all is 0.7PV.According to the determined concentration and slug size,we designed laboratory experiments to study the seepage law.The cores used in the experiments are thick heterogeneous cores with four layers.The experimental results show that: The production pressure of Huading polymer surfactant flooding after polymer flooding was significantly higher than that of Haibo polymer surfactant flooding.There is an oscillation trend of distributing rate of low permeability layer and high permeability layer by Hua ding polymer surfactant flooding,while the trend of distributing rate by Haibo polymer surfactant flooding was relatively smooth,which indicated that Huading polymer surfactant increased the recovery of remaining oil greater.The results of saturation model displacement experiments indicated that the producing degree of low permeability layer and high permeability layer by Huading I type polymer surfactant flooding was higher,while the swept volume in low permeability layer and high permeability layer by Haibo BI type polymer surfactant flooding was larger.The results and understanding of this paper can not only provide a theoretical basis for field application,but also has a guiding significance.