A visual investigation of enhanced heavy oil recovery by foam flooding after hot water injection

Hot water flooding is an important method for the development of heavy oil. But due to water channeling and low enthalpy, oil recovery by hot water flooding is very limited. In this paper, a two-dimensional visual experiment is conducted to intuitively study foam flowing characteristics and blocking mechanisms in porous media, as well as the microscopic mechanisms of enhancing heavy oil recovery by foam after hot water flooding. The experiment visually reproduces foam generation in porous media and the processes of hot water flooding and foam flooding. The results show that foam flows along the channels with lower flow resistance in oil layer and can effectively improve the sweep efficiency. Compared with pure hot water flooding, the ultimate sweep efficiency increases from 40.5% to 70.7% after foam injection. Moreover, foam can effectively displace the residual oil caused by hot water flooding. The ultimate oil recovery of thermal foam flooding is 67.54%, 31.30% higher than that of hot water flooding. This paper can provide reference for the study for foam and thermal foam flooding in heavy oil recovery. (C) 2016 Elsevier B.V. All rights reserved.