Study On The Effect Of Different Polymers On The Stability Of Emulsions Of Suizhong Crude Oil

Polymer flooding technology is an important technology in tertiary oil recovery,which plays a significant role in enhanced oil discovery.However,the treatment is very difficult because of the emulsified produced liquid containing polymers.In this paper,Suizhong crude oil was chosen as the research object.It was separated into four components by means of fluid-soild adsorption chromatogram and three components(resins,asphaltene,oil)by means of solvent extraction.The molecular weight,elementary composition,acid value,alkali nitrogen value,IR spectrum of crude oil,as well as the four components were investigated.The result showed that resin and asphaltene had relatively high activity,and contained more nitrogen,oxygen and sulfur.The molecular weight of asphaltene was the largest.The content of hetero atom and the unsaturation degree of four components was largest.Besides,its structure was complex.The stability of crude oil and the simulate emulsion of active components,as well as the effects of HPAM and AP-P4 on the stability of simulate oil emulsion,was systematicly investigated.The result showed that the stability of simulate oil emulsion was asphaltene>crude oil>resin>oil content.Although the addition of AP-P4 into the simulated system greatly strengthened the stability of the simulate emulsion,the difficulty of oil-water separation thereupon increased.The effects of AP-P4 and HPAM on the oil-water interfacial tension and dilatational viscoelasticity of crude oil and its components were studied.With the concentration of the polymer increasing,the interfacial tension in the aqueous phase of the toluene solution of crude oil,resin and asphaltene and aqueous phase increased first and decreased later.The interfacial tension can be reduced when the concentration of polymer was in a certain scope,and when the concentration of the polymer surpassed this scope,the interfacial tension began to increase,since the adsorption of the polymer beginning to replace the active components on the interface.The addition of AP-P4 and HPAM had unobvious influence effect on reducing the oil-water interfacial tension.With the polymer concentration increasing,the dilatational viscoelasticity of crude oil and its active components showed the trend that the dilatational modulus,the dilatational viscosity and the dilatational elasticity increased,and the phrase angle decreased.When the polymer was in a certain concentration,with the dilatational frequency increasing,the dilatational modulus and the dilatational elasticity increased gradually,while the dilatational viscosity and the phrase angle decreased gradually.AP-P4 can greatly improve the stability of the interfacial film.