Abstract:The development of LD 27-2 oilfield has entered the middle and late stage of steam stimulation. At present, the water content of the oilfield has risen rapidly, and the development effect of steam stimulation has deteriorated. In order to better carry out the reserve evaluation and development of the LD 27-2 oilfield. In this paper, the effects of heavy oil composition, temperature, oil-water emulsification, pressure, N2 dissolution and viscosity reducer on the viscosity of heavy oil in LD 27-2 oilfield were studied in detail. Then through the fluidity experiment, it is confirmed that the fluidity of the heavy oil in the reservoir is mainly affected by the viscosity, and it is clear that the temperature, the oil-water emulsification and the use of the viscosity reducer are the main factors affecting the viscosity of the heavy oil. When the temperature is raised from 50 °C to 100 °C, the viscosity of the heavy oil sample of the LD 27-2 oilfield is reduced from 3665 mPa?s to 172 mPa?s, which is reduced by 95.31%. At 50 °C, the viscosity of the 70% water content crude oil is 21.1 times the viscosity of the dehydrated crude oil; when the temperature was 50 °C and the viscosity reducer content was 1.0%, the viscosity reduction rate was 94%. Effectively avoiding or weakening the emulsification of oil-water to form a water-in-oil emulsion is an important way to effectively improve the development of oilfields.