Displacement of heavy-oil by gas at elevated temperatures and residual oil saturation (S-or) development on the walls of a square capillary were investigated through computational fluid dynamics (CFD). The displacements were carried out at 55 and 85 degrees C and compared to experimental data showing good quantitative and qualitatively agreement. On the basis of these results, the behavior of S-or was explored at 200 degrees C, a typical temperature of thermal oil recovery (steam injection) applications. It is shown that S-or decreases at higher temperatures for a fixed air injection velocity. This numerical study suggests that the S diminishes exponentially with time until it reaches a constant value along the square capillary during the displacements. It also indicates that when the contact angle is increased, the retention of oil decreases lineally. Above 60 degrees, oil is completely swept at 85 degrees C and 200 degrees C. This is the first attempt with CFD to analyze the retention of oil in the pores of a reservoir after the application of thermal methods. CFD approach to model this microscopic phenomenon is promising to carry out further research at temperature and pressure conditions that are very difficult to generate at the microscopic scale in laboratory experiments. (C) 2015 Elsevier Ltd. All rights reserved.