Emulsification And Viscosity Reduction Of Heavy Oil By Mucopolysaccharides

In recent years,due to the gradual depletion of the reservoir,people have to pay attention to the heavy and heavy oil in the oil deposits.In this experiment,the emulsification and viscosity reduction of heavy oil were studied by mucopolysaccharide,an extracellular product secreted by streptococcus epizootic.It mainly includes three parts:the preparation and purification of mucopolysaccharide,the performance study of mucopolysaccharide as oilfield displacement agent,and the viscosity reduction experiment of mucopolysaccharide on heavy oil emulsification.First,streptococcus epizoophilus was cultured in a 5 L fermenter under optimal fermentation conditions to obtain the fermentation broth.Multiple series methods were used to remove bacteria and other insoluble impurities with large volume in the fermentation broth:ethanol decolorization flocculation,diatomite adsorption,and three times plate and frame filtration.The final solution at 600 nm had an absorbance of 0.002,which could be regarded as the basic bacteria removal.Then,the freeze-thaw--Sevage combined method was used to remove the soluble protein in the solution.The protein removal rate reached 72.89%,and the protein content in the solution was only 0.0212 mg/ml.Finally,11.63 g of refined mucopolysaccharide A was obtained through ethanol flocculation and vacuum drying.Secondly,in order to better promote the application of mucopolysaccharide to oil field exploitation and transportation,the influence factors of viscosity of mucopolysaccharide A and its rheological properties were systematically studied.The results showed that mucopolysaccharide A had good high temperature resistance,rheological property,salt resistance,shear resistance and strong chemical stability.The influence of each factor on the viscosity of mucopolysaccharide was successively the mucopolysaccharide concentration>ph>temperature>time.Therefore,it is further indicated that mucopolysaccharide A is a kind of oil recovery displacement agent with excellent properties,which can emulsify heavy oil to reduce viscosity and improve oil recovery.At last,mucopolysaccharide A was used to carry out the emulsification and viscosity reduction test for liaohe heavy and heavy oil.By investigating the influencing factors of viscous oil emulsification and viscosity reduction,the technological conditions of viscous viscosity reduction for mucopolysaccharide A heavy oil emulsification were determined,the experimental results show that the oil/water mass ratio 6:4,polysaccharide,mass concentration of 75 mg/L temperature 25?,the speed of 160 r/min of shaking table under the condition of emulsifying 7 h,heavy oil viscosity by 87000 mPa to 180.3 mPa.s,adhesion rate of 99.7%.Demulsification can be achieved after viscous oil emulsified by mucopolysaccharide A is left at room temperature for 24 h,and the polysaccharide aqueous solution after demulsification can be reused for 2 batches,effectively reducing the cost of production of polysaccharide emulsifier and treatment of viscous oil stripping water.The polysaccharide emulsifier can be widely used in viscous oil emulsification and viscosity reduction recovery and transportation.