Mimic oil recovery with a SDBS-dodecane-silica gel system

The wettability of the solid powder of silica gel was determined via a modi fied Washburn equation expressed as contact angles. The interfacial tension (gamma) between the dodecane and the dilute sodium dodecyl benzene sulfona te (SDBS) aqueous solution was obtained using the spinning drop (gamma < 10 mN m(-1)) or drop vol;me methods (<gamma> > 10 mN m(-1)). Contact angle ch anges for SDBS aqueous solutions on the surface of a silica gel powder were studied. The average aggregation number of SDBS micelles in aqueous soluti on was determined using the fluorescence quenching method. The relationship between the wettability of the powder surface, the critical micelle concen tration (CMC) of SDBS and the mimic oil recovery of the resident oil on the powder surface has been explored. It has been found that good residual oil recovery was achieved by surface wettability changes at the interfacial te nsions around 4-5 mN m(-1). which is far from the 'ultra low' condition (le ss than or equal to 10(-3) mN m(-1)). (C) 2001 Elsevier Science B.V. All ri ghts reserved.