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Experimental Investigation on the Interactions between Asphaltenes and Comb-like Octadecyl Acrylate (OA) Polymeric Flow Improvers at the Model Oil/Water Interface

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journal contribution
posted on 20.02.2020, 12:46 by Daiwei Liu, Hao Zhang, Chuanxian Li, Fei Yang, Guangyu Sun, Bo Yao
In the crude oil production, comb-like octadecyl acrylate (OA) polymers are usually added into the well as flow improver, causing the existence of OA polymers in the produced fluid. OA polymers and asphaltenes in the crude oil could both adsorb at the oil/water interface and form a composite interfacial layer, thus affecting the stability of crude oil emulsion. In this study, the interactions between OA polymers and asphaltenes are explored. OA polymers with different polar groups are first synthesized and their molecular structures are then analyzed. In order to investigate the adsorption behaviors of asphaltenes and OA polymers, the dynamic interfacial tension is detected. The influences of the interactions between OA polymers and asphaltenes on the interfacial tension are obtained by analyzing the adsorption behaviors of single system and binary system. The results show that the OA polymers join in the formation of interfacial layer by competitive adsorption with asphaltenes. The interfacial dilational modulus is then determined with a method of small-amplitude oscillation. The modulus decreases with the addition of OA polymers, indicating that the intensity of interfacial layer is weakened. The conductivity experiment, asphaltene precipitation experiment, and dynamic lighting scattering experiment are conducted jointly to investigate the dispersion state of asphaltenes affected by OA polymers. The polar moieties of OA polymers can interact with asphaltenes and form composite particles containing alkyl side chains with strong oil compatibilities, thus improving the dispersion state of asphaltenes. Among all the synthesized OA polymers, the OA polymer with benzene rings possesses the strongest effects on asphaltenes.