Abstract: In order to evaluate the adaptability of surfactant WLW for exploit of reservoir of crude oil with extra low permeability in Changqing Jingan oilfield,the imbibition characteristics,emulsion performance and interfacial tension between crude oil and the surfactant WLW solution as well as the oil displacement test using physical simulated rock core were studied in experiment and in field application.Results show that the surfactant WLW stimulates the imbibition efficiency of the injected water;when the injection mass fraction of surfactant system is 0.2%,the oil displacement efficiency will increase 5% in this low permeability reservoir,and in the range of the low permeability,the lower the permeability is,the better the surfactant improves the oil displacement efficiency.From 2011 to 2013,field test of oil well group A1 and A2 in Changqing Jingan oilfield was conducted and 4 781 t of crude oil increased.Obviously,the surfactant can enhance the oil recovery of extra low permeability reservoirs.

Key words: surfactant, extra low permeability reservoir, oil displacement efficiency, imbibition efficiency, field test