Performance evaluation of a novel viscosity-reducing agent for heavy oil

Abstract

Heavy oil has high viscosity, high content of resins-asphaltenes and poor fluidity, which makes it difficult to produce. In the early research, a novel viscosity-reducing agent with high molecular weights and various active groups was synthesized in the laboratory. Ion composition analysis of wastewater and heavy oil viscosity test of Jincai 27 well were carried out. The emulsifying and viscosity reducing properties of a novel viscosity-reducing agent for heavy oil under low shear condition were evaluated by water content change of emulsion phase and viscosity reduction rate. The results showed that under 50 °C and low shear (10∼20s−1) condition, the viscosity-reducing agent solution had a fast emulsifying speed for the heavy oil. The O/W emulsion with good emulsion stability formed after about 60min shear. The viscosity reduction rate for the heavy oil was above 90%. The emulsion micrographs showed that the emulsion was highly dispersed and the particle size was uniform with diameter of 2 microns or even lower. The viscosity value of viscosity-reducing agent solution with concentration higher than 1200 mg/L could reach 25.0mPa.s under 8.0s−1 shear rate and 50°C, which indicated that it had a certain thickening property. Artificial core flooding experiments showed that viscosity-reducing agent flooding could increase heavy oil recovery by more than 10% compared with water flooding.