Study On The Synthesis And Performance Of Emulsified Viscosity Reduction Of Heavy Oil Reservoir

The reserves of heavy oil resources are abundant in China,and the exploitation of heavy oil resources is of great significance to solve the problem of oil resource shortage.However,due to the high asphaltene and colloid content in heavy oil,its high viscosity and poor fluidity and most of oil fields in China are high-salinity oil reservoirs.The high-salt and high-viscosity oil reservoir environment makes the development of heavy oil difficult to exploit.The emulsifying viscosity reducers used in conventional heavy oil reservoirs generally have strong selectivity and poor temperature and salt resistance.Therefore,designing an emulsified viscosity reducer that is resistant to temperature and salt and has universal applicability will make a great contribution to the enhanced oil recovery.In this paper,aiming at the problems existing in the emulsification and viscosity reduction of heavy oil by oil displacement emulsification and viscosity reduction agents,a temperature-and salt-tolerant anionic-nonionic surfactant fatty alcohol polyoxyethylene ether sulfonate sodium was synthesized.The specific research results are as follows:Firstly,through the orthogonal experiment method,the effect of the types of raw materials(AEO-7,NP-10,OP-10),reaction temperature,and reaction time were investigated,and the best raw material type was optimized as AEO-7,the reaction temperature was 60?and the reaction time was 4h.On this basis,the effect of the material ratio,reaction temperature and reaction time on the fatty alcohol polyoxyethylene ether sulfonate sodium was investigated,and the optimal reaction conditions were optimized as follows:the material ratio was 1:1.3,and the reaction temperature was 70?,the reaction time was 5 h.The effect of emulsification viscosity-reducing agent concentration,oil-water ratio,aging temperature,aging time and salinity had been systematically studied.The experimental results showed that as the concentration of emulsifying viscosity-reducing agent increased,the emulsification effect was better,The best emulsification viscosity reducer concentration was in the range of 0.6%to 0.8%.The fatty alcohol polyoxyethylene ether sulfonate system had good temperature resistance and salt resistance,and can withstand temperatures up to 300?,and can be aged at 200?for 10 d,and still had good stability performance.When the concentration was less than 15000 mg/L and Ca²⁺and Mg²⁺were less than 3000 mg/L,it had good emulsification and viscosity reduction performance.The effect of the combination of fatty alcohol polyoxyethylene ether sulfonate sodium and different cationic surfactants(CTAC,CTAB,DTAC)on the interfacial tension was investigated,and the interfacial tension of heavy oil could be reduced to the order of 10^-2.The oil displacement performance of fatty alcohol polyoxyethylene ether sulfonate sodium and its compound system under different temperature conditions were investigated.For fatty alcohol polyoxyethylene ether sulfonate sodium compound system,the temperature increased from 100?to 300?,The oil displacement efficiency can be increased by 8.4%.The oil displacement efficiency under different interfacial tension conditions was investigated.When the interfacial tension increased to the order of 10^-2and the temperature was 300?,the oil displacement efficiency can increased by 15.0%.