Research Of Microbial-Chemical Compound System For Reducing Viscosity Of Heavy Oil

With the rapid and sustained development of economy,the requirement for resources is growing day by day.While oil as the important support of our country’s economic strategy,whether its supply can meet the needs of economic development is related to whole national production.In our country,the heavy oil shares a large proportion,and its mining ways are different from conventional oil because of its high viscosity and poor flowing ability.For now,the main ways to exploit heavy oil are steam injection and chemical methods.The compound method for reducing viscosity of heavy oil is combining microbes with chemical reagents,clean and green.It has considerable application prospect.In this paper,the surfactant which was produced by the Pseudomonas aeruginosa ATCC9027 was been used for emulsifying crude oil,then the viscosity of heavy oil was reduced.Firstly,the strains was activated to ensure they were in the most vigorous growth stage,then their culture was amplified by slant culture and shaking culture.To determine the growth law of bacteria dynamically,biomass in fermentation broth and the surface tension of the fermentation broth were traced.The change of bacterial metabolites was determined by Anthrone-sulfuric method.The extraction and purification process of metabolites were studied.Further,they were identified as rhamnolipid by NMR and IR spectrum.Their viscosity reducing performance was tested.The results indicated that the difference of viscosity reducing performance between pure rhamnolipid and fermentation broth was little.The viscosity-reducing rates were about 62%.In the end,the fermentation conditions of the strains were optimized and the optimum medium was defined.Five kinds of glucosides with various side chains were prepared by the reaction of glucose with n-octanol,n-decanol,n-dodecanol,n-tetradecanol,n-hexadecanol,respectively.Sucrose laurate was prepared by the reaction of sucrose with ethyl laurate.They were characterized by NMR and FTIR.And their viscosity reducing performance was investigated.The test results showed that n-tetradecyl glucoside had the best viscosity reducing performance among the five kinds of glucosides,and sucrose laurate also had good viscosity reducing performance.The synthesis conditions of n-tetradecyl glucoside and sucrose laurate were studied,respectively,the optimum synthesis conditions were proved.The viscosity reducing performance of bacterial metabolites can not meet the request.To further improve the viscosity reducing performance,a new complex viscosity reducer was prepared from fermentation broth,n-tetradecyl glucoside,sucrose laurate and polyether D-90.The optimum formula of composite viscosity reducer was determined by the orthogonal test,and its viscosity reduction efficiency was ideal.In order to test the performance of microbialchemical complex viscosity reducer in practice,the oil recovery efficiency was determined by sand pack experiment.The effects of different oil samples,different dosage and different temperature on the recovery efficiency and recovery time were examined,which could provide help in enhancing oil field recovery.