Stutd On Betaine Surfactant Flooding System

Under the condition of growing tension in the energy, enhanced oil recovery EOR technology has become a major issue in study of oil exploitation. Surfactant or surfactant mixed system for the three oil production technology has been widespread concern. In view of the current low permeability oil reservoirs in conventional water flooding low recovery rate, poor development effect, high salinity and high temperature reservoir on the surfactant flooding requirements of high status, this paper chooses a carboxylic acid betaine amphoteric surfactant EAO as main agent and analyzes its performance. The performance of EAO has been improved by adding other additives. According to main reagent EAO performance and combined system performance, the optimum formulae of the mixed system have been obtained.The results show that the surfactant has low critical micelle concentration (CMC), good emulsification properties, temperature resistance, salt resistance and compatibility, lower ground absorption loss and good oil displacement effect, through evaluation of the main agent EAO performance. However, oil-water interfacial tension has not achieved ultra-low and the price of EAO is high. Moreover, the interfacial tension of the solution above the critical micelle concentration needs to further reduce. Therefore, ultra-low interfacial tension could be achieved by mixing other additives.In order to make up the performance deficiency of the main agent, this paper investigates two complex systems. One is various alcohols (dodecanol, octanol, n-butyl alcohol, isopropanol) and EAO mixture. The other is other surfactants and EAO mixture. The results show that two good formulae are obtained which are EAO:OP-10=3:1using concentration of0.3%, and EAO:fluorocarbon=900:1using concentration of0.3%. When mixing with OP-10, the amount and cost of the used main agent can be reduced. When mixing with fluorocarbon, oil recovery can be greatly improved. Furthermore, these two kinds of oil displacement system formula have strong salt resistance. However, the temperature resistance of EAO/OP-10complex system is poor which can be used in lowtemperature reservoir. While the temperature resistance of EAO/fluorocarbon complexsystem is good, especially in the60degrees at the concentration of0.3%, and can achieveultra low interfacial tension10-3mN/m. Therefore, this system can be used for lowpermeability, high salinity reservoir and significantly enhancing the oil recovery.