Study On Temperature And Salt Resistance Surfactant Flooding System

Surfactant flooding,an enhanced oil recovery technology in the oilfields ,which is widely applied at home and abroad, has achieved good economic and social benefits.However, because of the poor resistance to temperature and salinity, ordinary surfactant can not be used in high-temperature or salty layers, whose application subjects to certain restrictions. So it is significant to develop surfactant resistant to temperature and salinity in order to enlarge application scope and enhance oil recovery. In this paper, we have examined surface activity, interfacial activity, and emulsifying capacity of single surfactant. Surfactant adsorption and biological toxicity of APG has been evaluated. Compared with ionic Surfactant, non-ionic Surfactant has a lower critical micelle concentration, and the effect of interfacial tension reduction is better than anionic surfactant while compounding with the alkali. In addition, emulsion capacity of non-ionic surfactants is superior to ionic surfactants, with an emulsion up to 87%. Whose adsorption is lower than ordinary surfactant, Static adsorption and dynamic adsorption of APG is 0.846mg/g sand and 0.123mg/g sand respectively , and it is nontoxic and friendly to the environment..On the basis of evaluation of single surfactant, four surfactant flooding systems with low interfacial tension which is resistant to temperature and salinity has been selected through studying different surfactants mixed systems. Its emulsifying capacity and resistance to temperature and salinity has also been assessed. The results reveal that the optimized system is better than single surfactant in emulsification and resistance to temperature and salinity, whose limitation to temperature, Na⁺ and Ca²⁺ is 140-160℃, 15000-50000mg/L and 1500-4500mg/L respectively. Finally, the effectiveness of displacement of the compouding system was investigated. Experiment shows that oil recovery increases by 19.3% compared with water flooding system. All in all, the anti-temperature and anti-salt surfactant flooding system has several advantages,such as high interfacial activity salt-tolerant, low cost, friendly to environment, which deserves a promising future in wide applicationn in oilfeilds.