| The class ? reservoir in the Sartu Oilfield is highly heterogeneous and show serious interlayer interference,which greatly influence the development and recovery of the oil field.The ASP flooding field test shows that the emulsion plays an important role in improving the recovery factor.Emulsified compound flooding could enlarge sweep volume of polymer and improve oil displacement efficiency.The proportion of emulsion system and related supporting technologies in stabilizing oil and controlling production in high water content oil fields is increasing.With increasing water content in oil reservoirs and complexity of water flooding,emulsion flooding has gradually become an important technology for water and polymer flooding.and has good application prospects.In this paper,on the basis of exploring the influencing factors of the emulsification,the experiment of emulsion percolation characteristics was carried out by using the stable emulsion system.By measuring the droplet distribution and pressure change of the dispersed phase of emulsion system,the profile control characteristics and migration rules of emulsion during its migration in porous media are explored,and the matching relationship between different emulsion systems and class III reservoir is established.Then,the stable emulsion system is used to simulate the underground emulsification process,the parallel core flooding experiment is carried out,and the effect of the emulsion system is compared with that of the ASP system,and the adjustment effect of the emulsion on the interlayer interference under the conditions of different emulsification degree and different permeability contrast is studied.The results show that the stability of the emulsion is related to the shearing strength,water content,and the type and concentration of the chemicals.There is a critical value of shear strength,and the best shear strength is 11000r/ min.The higher the water content is,the worse the stability of crude oil emulsion is.The type and concentration of surfactant play a major role in the emulsification of ASP system,and the chemical agents interact in the emulsification of ASP system.The migration process of emulsion is related to resistance coefficient,chemical viscosity and core permeability.The emulsion droplets flowing through porous media will pass through porous media in the way of deformation,fragmentation or demulsification.When the matching relationship between the particle size of emulsion and the pore diameter of core is good,the peak value of migration resistance of emulsion in porous media is high,which has a strong sealing ability for pores.In the oil displacement experiment,the oil displacement effect of emulsion flooding is better than that of ASP flooding.For parallel-core with average permeability of 40 m D and permeability contrast of 2,the emulsion flooding can enhance oil recovery by 21.16% compared to that of the water flooding.With increasing core permeability ratio,the recovery rate of the emulsion flooding will further increase.The ability of profile control for the emulsion systems are stronger than those of the ASP systems.The emulsion can reduce the interlayer difference between the high and low permeable layers,enlarge the sweep volume,enhanced the oil recovery,thus achieve the effect of adjusting the interlayer interference to some extent.When the permeability contrast is in a small range,the stronger the heterogeneity of the porous media,the higher the degree of emulsification of the displacement fluid,and the better the adjustment effect of the emulsification on the interlayer interference. |
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