The Synthesis Of Comb-like Polymer And Its Effect On The Rheological Behavior Of Heavy Crude Oil

As with the world-wide reduction of conventional oil, the utilization of the heavy or waxy oil are more and more common. So to develop the proper flow modifier in accordance with the properties of oil is becoming critical.Poly(2-acrylamido-2-methyl propane sulfonic acid-co-Acrylic acid) grafted with n-amines named as P-X-Y targeting to emulsify heavy crude oil and three series of comb-copolymers named MAC, AMACs and PMACs used as pour point depressant (PPD) were synthesized.1H-NMR was used to characterize their chemical structures. Rheology methods and Polarizing light microscopy were used to access the above copolymers.In P-X-Y series, four kinds of P-X-Y except P-12-4aqueous solutions can emulsify the crude oil with low mixing energy. Polymer P-X-Y with a relatively longer alkyl side chain n-amines/acrylic acid increases the stability of emulsions and decreases the viscosity of emulsions. P-X-Y with a medium degree of side chain substitution shows optimal stability and viscosity of stabilizing emulsions. Zero shear viscosity of emulsions stabilized by P-16-4or P-12-4decrease two orders of magnitude compared with crude oil which turn out to be suitable emulsifying agents for high asphaltic crude oil.The effect of copolymers used as PPD on the rheology of waxy model oil as well as waxy crude oil with asphaltenes was studied. Compared to MAC2, new designed copolymers PMAC and AMAC showed better improvement to waxy gels, of which PMAC1.0and AMAC1.0with medium substitution degree seemed to reach a balance to get optimal interactions with paraffins and asphaltenes in the model oil or crude oil and could improved them most. AMACs performed better than PMACs that probably caused by the selectivity of aromatics in asphaltenes towards aniline unit and oxyethyl unit. The waxy crude oil shows viscoplastic profile at studied temperature, which can be best presented by the Casson model.