The Influence Of The New Treatments On The Oil-water Interface And The Emulsion Stability Of The Tahe Heavy Oil

The heavy oil produced from Tahe No.2 combination has high viscosity and its demulsification is rather difficult.To obtain the viscosity reducing and demulsification mechanism of the heavy oil and select the suitable viscosity reducer and demulsifier,the influence of the new treatments including different kinds of viscosity reducers and demulsifiers on the oil-water interfacial properties and the emulsion stability of the dehydration crude oil and model oils with petroleumfractions was studied.The results show that the water soluble viscosity reducer was good for the formation of O/W emulsion because it reduced the oil-water interfacial tension of the dehydration crude oil and petroleum fractions and increased the Zeta potential of the O/W emulsion.The oil soluble viscosity reducer benefitted for dissolving and dispersing the asphaltene component,thereby reducing the viscosity of the produced liquid,increasing the interfacial film strength and improving the emulsion stability.When the viscosity reducers were mixed,the oil-water interfacial tension was decreased,the interfacial film strength and the Zeta potential were increased,accordingly the emulsion stability was greatly improved and the effect of viscosity reduction was better.When the total concentration was 3000 mg/ L and the ratio of the water soluble viscosity reducer concentration and the oil soluble viscosity reducer concentration was 2:1 or 1:1,the emulsion after 7 day still had good emulsionfication phenomenon and the viscosity decreased significantly.The water soluble demulsifier containing surfactant reduced the oil-water interfacial tension,dissolved some asphaltene by increasing the interfacial film strength of the colloid and wax,and made the interfacial film strength of the crude oil decreased,the emulsion stability decreased and the demulsification efficiency was better.When the concentration of the demulsifier 4# and 2# was greater than 600 mg/L,they had great effect on demulsification efficiency.The oil soluble demulsifier had little effect on the surface and the oil-water interfacial properties,and its demulsification efficiency was poor.