Experimental Investigation of Hot Polymer Flooding for Viscous Oil Recovery

Abstract Hot polymer flooding has been proposed as a hybrid process for heavy oils that combines moderate heating (60-80 °C) with polymer mobility control to extend the applicability of polymer flooding to more viscous oils. However, most of the studies are simulation-based, and experimental data remain limited. This study presents a controlled bench-scale experimental investigation of hot polymer flooding for viscous oil recovery. Flooding experiments were conducted in a cylindrical glass holder packed with sand using a viscous oil (~1600 cp) and a partially hydrolyzed polyacrylamide solution. Four flooding schemes—water flooding, cold polymer flooding, hot water flooding, and hot polymer flooding—were systematically evaluated under identical injection rate and boundary conditions. Oil recovery factor, oil cut, pressure drop, and inlet and outlet temperatures were continuously monitored to characterize displacement performance and thermal behavior. The results show that water flooding exhibits early breakthrough and poor sweep efficiency due to high mobility contrast. Polymer flooding significantly improves sweep efficiency and recovery through enhanced mobility control. Hot water flooding reduces oil viscosity but remains prone to unstable displacement in the absence of mobility control. Hot polymer flooding combines viscosity reduction and mobility control, yielding the highest recovery (~85%) and the most stable displacement behavior among the tested schemes. These experiments provide direct laboratory evidence of the complementary roles of temperature and polymer in viscous oil displacement and help bridge the gap between simulation studies and experimental validation of hot polymer flooding.