Synthesis and laboratory evaluation of iso-tridecyloxypolyethylene glycol acrylate copolymers as potential viscosity reducers for heavy oil

As driven by the increase in global fuel demand and decrease in worldwide reserves of conventional oil, it is important to develop new production technologies for heavy oil. In this work, copolymers PAAI(7), PAAI(10), and PAAI(15) were synthesized and evaluated as potential viscosity reducers for heavy oil. iso-Tridecyloxypolyethylene glycol acrylates (I13C(x)AA, x = 7, 10, 15), acrylic amide (AM), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) were polymerized to give the copolymers PAAI(x), respectively. Copolymers PAAI(x) were characterized by FTIR, H-1 NMR spectroscopy, and TGA and showed good thermal stabilities as the decomposition temperature was above 350 degrees C. Their viscosity-average molecular weights were measured as in the range between 6.53 x 10(6) and 10.58 x 10(6) g/mol. The effects of temperature, shear rate, and salinity on the viscosity of polymer solutions were studied, and PAAI(x) had reasonable rheological properties. The solutions of PAAI(x) in formation water could emulsify heavy oil sample to form oil-in-water emulsion when mass ratio of oil:water was in the range of 6:4-2:8, respectively. The rates of reduction in viscosity of emulsions compared with that of original oil sample were 53.5%-97.5% at 50 degrees C under shear rate of 20 s(-1). The effects of oil:water ratio, emulsifying temperature, and shear rate on the viscosities of emulsions were extensively studied, and the effect of the polymer structure on the emulsification and viscosity reduction of heavy oil was also discussed. Among three copolymers, PAAI(15) formed the most stable emulsion with heavy oil and the emulsion had the lowest viscosity. PAAI(15) had the potential for further study.