In order to resolve the problem whether more excellent combinational demulsifiers for north shaanxi oil fields of Changqing could be made from the commercial demulsifiers used for the oil fields at present,four excellent demulsifiers for the representative crude oils from Baota district,Ansai and Zichang in the oil fields,YT-100,GT-940,HQ96-1,SP-169,were screened out.One combinational demulsifier was formed by the combination of one of the four demulsifiers with another of the four in different proportions,and the capability of combinational demulsifiers in demulsification/dehydration was compared at total demulsifier use level of 100mg/L at 55℃ in 2h by bottle tests.The dehydrating efficiency of combinational demulsifier of GT-940 and HQ96-1 was higher than GT-940 or HQ96-1 for all the crude oils,and the proportion of GT-940 to HQ96-1 in combinational demulsifier which dehydrating efficiency was highest was respectively 4∶1,4∶1 and 3∶2 for Baota district,Ansai and Zichang crude oils.The dehydrating velocity of combinational demulsifier of YT-100 and GT-940 was higher than YT-100 or GT-940 for Ansai crude oil and the proportion of YT-100 to GT-940 in the combinational demulsifier is 4∶1.The dehydrating efficiency of combinational demulsifier of YT-100 and HQ96-1 was higher than YT-100 or HQ96-1 for Zichang crude oil and the proportion of YT-100 to HQ96-1 in combinational demulsifier which dehydrating efficiency was highest is 2∶3.The dehydrating efficiency of combinational demulsifier of SP-169 and HQ96-1 is higher than SP-169 or HQ96-1 for Baota district crude oil and the proportion of SP-169 to HQ96-1 in combinational demulsifier which dehydrating effciency was highest is 2∶3.
