Feasibility Of Emulsification Flooding And Profile Control In Mid-high Permeability Reservoir

Emulsification of oil and water in the process of displacement is one of important mechanisms for enhancing oil recovery.It has important theoretical and practical significance to carry out further research.In this paper,the influence factors of emulsification of oil and water in the reservoir and the feasibility of enhancing oil recovery are studied with a main method of simulation experiments.In order to ensure the repeatability of the experimental conditions,the emulsion particle size is controlled as the standard,and the method of stirring is selected as the preparation method of the emulsion sample.The experimental results show that the particle size of emulsion is decreased while the mixing rate of emulsion increases,which provides inspiration for the study of oil and water emulsion conditions in the process of oil displacement.The emulsion simulation experiment was carried out to study the influence of various factors on the emulsification of oil and water in the oil reservoir.Based on the experimental results,the oil-water emulsification condition coefficient Em is built to reflect the influence of the dynamic conditions like the injection velocity,migration distance and permeability on the effect of oil and water emulsification in porous media.For a specific oil and water system,there is a corresponding critical emulsification condition coefficient Emc.Only when Em ?Emc,oil and water emulsifies in the reservoir.The experimental results also show that the correlation between the emulsifying ability of oil and water and the interfacial tension is not obvious when the interfacial tension is lower than 10-1 mN/m.The matching relationship between emulsion particle size and displacement efficiency was studied using the visual microscopic model.It is found from the experimental observations that there exists a median particle size(7.7?m)to match a specific core permeability(1.6?m2).Under the condition,the startup of micro heterogeneous residual oil can be observed clearly.The increase of the oil displacement efficiency can be as high as 14.8%in the base of water flooding.Emulsion profile control-oil displacement simulation experiment is done in artificial heterogeneous reservoir model.The increase of oil recovery is limited when injecting single emulsifier plug after water flooding.However,the increase of oil recovery is 10%in the base of water flooding using profile control agent and emulsifier plug.It is indicated that the emulsifier fully contacts remaining oil with the barrier of the profile control agent is a necessary condition for the realization of emulsion profile control in heterogeneous reservoirs.