Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

Abstract

The production, processing, and transportation of heavy crude oil (HCO) is difficult because of its high viscosity. For practical applications, information on the rheological behavior of HCO plays an important role, especially in flow assurance investigations. In this work, six different imidazolium ionic liquids (ILs) were tested for their effects on the rheological behavior of HCO under high-pressure and high-temperature conditions. The rheological studies were carried out at three different pressures (0.1, 5, and 10 MPa) and four experimental temperatures (298.15, 323.15, 348.15, and 373.15 K). The HCO + IL systems showed favorable viscosity reductions of 26.5% and 31.5% for the systems of HCO + 1-butyl-3-methylimidazolium chloride ([BMIM]+[Cl]−) and HCO + 1-octyl-3-methylimidazolium chloride ([OMIM]+[Cl]−), respectively, at 298.15 K and 0.1 MPa as compared to the pure HCO system. At 298.15 K and 0.1 MPa, the yield stress of the HCO + IL systems was reduced by about 15–20%, whereas when the temperature...