Inhibiting asphaltenes from agglomeration by controlling the length of aliphatic branches and polarity of anions in imidazolyl ionic liquid polymers

Abstract

Ionic liquid polymers have been reported being capable of inhibiting the precipitation of asphaltenes, and are expected to further solve problems such as the reduction of oil flowability, reservoir plugging, and blockage of transportation pipeline. In this article, a series of imidazolium‐based ionic liquids containing long aliphatic branches and different anions (Br−, DBSA−, and DEHP−) were synthesized by free radical polymerization and to explore the influence of polymers on asphaltenes, model oil containing Tahe asphaltenes was prepared. The initial precipitation point (IPP), particle size of asphaltenes in model oil were measured, and morphology of asphaltene precipitates was observed by microscope. The rheological behaviors of Tahe crude oil in the presence ionic liquid polymers were examined by analyzing the viscosity–temperature curves. The results show that among all the synthesized ionic liquid polymers, the [IM16E18] [DBSA] can increase the IPP from 36% to 69%, reduce the size of asphaltene precipitates by 76.3%, and decrease the viscosity of crude oil by 64.9% at the dosage of 0.5%. The ionic liquid polymers can inhibit asphaltene precipitation at a low concentration of 50 ppm, which are one of promising inhibitors for heavy crude oil containing asphaltenes.