Dynamic interfacial tension behaviors between Guerbet betaine surfactants solution and Daqing crude oil

► The effect of ethylene oxide groups was studied. ► Both of GC16 (3) and GC20 (5) could reduce DIFT to low value. ► When the mass ratio of GC16 (3)/GC20 (5) was 9:1, the DIFT could reach ultralow value. ► The GC16 (3)/GC20 (5) compound system showed a certain temperature resistance.