Synthesis And Evaluation Of The Viscosity Reducer For TK1073 Oil In Tahe Oil Field

With the full development of domestic oil fields, the scope and extent of the exploitation of heavy oil is growing. The characteristics of heavy oil are high density, viscosity, and high content of resin and asphaltene. These bring difficulty in heavy oil production and transportation. As a result, research on heavy oil viscosity reducer is of profound theoretical and practical significance.Tahe Area 10 is typical super-heavy oil with the characteristics of"three high and one low". The key point to reduce the viscosity is to synthesize a selective reducer. Based on domestic and foreign literatures, a kind of viscosity reducer for Tahe heavy oil was synthesized and the synthesis conditions were determined. What's more, it was characterized and its performance was evaluated. Lastly, the mechanism of viscosity reduction process using this viscosity reducer was discussed initially.Styrene, butyl methacrylate and maleic anhydride were used as a polymerization monomers, toluene as solvent and azobisisobutyronitrile as the initiator of synthetic oil-soluble viscosity reducer, its viscosity reduction was evaluated by test. The effects of the monomer ratio, reaction temperature, initiator dosage, reaction time on product performance were discussed. And the optimum reaction conditions were confirmed: reaction temperature 70℃, reaction time 7h, initiator dosage 3‰, n-butyl methacrylate: Styrene: Maleic anhydride monomer molar ratio of 8:3:1.5. The polymer structure and composition were characterized.The mechanism of the viscosity reduction with oil-soluble viscosity reducer was explorated initially. The results showed that the viscosity was reduced through the interaction of viscosity reducer with resin and asphaltene. At the same time, the intrinsic viscosity, the polar group and the ester chain also have effect on the viscosity reduction. The viscosity reduction of viscosity reducer was evaluated on the dosing temperature, dosage, combination of surfactant and compatibility with the demulsifier. The result showed that the combination effect of polymer and cetyltrimethylammonium bromide was better than others. When the proportion of cetyltrimethylammonium bromide to the mixed reducer was 35%, the viscosity reduction rate could reach about 39%. Viscosity-temperature test and rheological test were made on crude oil with and without viscosity reducer and the effects of different amounts of viscosity reducer on demulsification experiment were discussed. The result indicated that synthetic viscosity reducer can obtain better results than those which were using in Tahe oil filed, and it can compatible well with demulsifier.