Abstract:Aiming at the problems of unsatisfactory injection production ratio in the actual oil production and development process of Yanhua 182 Well Group, low production and low energy of development wells, high salinity, high calcium and magnesium ions in formation water resulting in the failure of conventional surfactant, a system of surfactant flooding with anti-salt was prepared. Without chelating agent and stabilizer, the system of surfactant flooding consisted of PPM-12(bis{[(N-methylN-(3- dodecanoxy-2-hydroxyl) propyl-N-(2-hydroxyl-3-sulfonic acid sodium) propyl] methylene} ammonium chlorides),AES-12 (sodium lauryl ether sulfate) and OB-2 (dodecyl dimethylamine oxide). The optimum total concentration of surfactant flooding system was 0.3wt%, and the suitable weight ratio range was 4:1:1-1:1:4. The optimum ratio is 2:1:3, and the oil-water interfacial tension can reach the lowest value (0.0012 mN.m-1). The adsorption, emulsification, salt resistance of the composite surfactant flooding system was studied under optimum conditions. The results of adsorption performance showed that the system was still in the order of 10-3 mN.m-1 after six adsorption. The results of emulsification showed that the water separation time of the system was 3995s. The experimental results of resistance to sodium, calcium and magnisesium ions showed that the system could reach the order of 10-3 mN. m-1 in the range of sodium, calcium and magnesium ions in the oilfield. Magnesium ions have the greatest influence on the interfacial tension of the system, followed by calcium ions and sodium ions. Experiments show that the PPM-12, AES-12 and OB-2 compound system is suitable for EOR of Chang 6 reservoir of Hua 182 well groups, with an average EOR of 10.3%. It has a good application prospect in similar high salt and low permeability reservoirs.