Keywords: 
• heavy oil reservoir /
• steam stimulation /
• foam flooding /
• flue gas /
• nitrogen /
• parallel dual-pipe test /
• numerical simulation

Abstract: With consideration of low thermal conducting efficiency induced by insufficiency in energy and severe steam channeling during steam stimulation, researches have been conducted through indoor physical simulation and numerical simulation by adding gas and high-temperature foam to enhance performances of steam stimulation. First of all, comprehensive foam indicators have been introduced to identify the optimal foaming agent. Secondly, four indoor parallel dual-pipe tests, namely pure steam flooding, steam-flue gas foam flooding, steam-nitrogen foam flooding and steam-nitrogen flooding, were performed. Test results show under identical flooding conditions, both steam-flue gas foam flooding and steam-nitrogen foam flooding can effectively seal off high-permeability channels to mobilize low-permeability channels. Compared with pure steam flooding, the new technique can enhance oil recovery by 28.98% and 26.04%, respectively. The steam-nitrogen flooding displayed limited profile-control performances because it failed to mobilize low-permeability channels effectively. It has improved oil recovery by 10.56% higher than that of pure steam flooding. With consideration of the results of physical simulation, numerical simulation has been performed to study the impact of formation parameters on the production performances of flue gas-foam assisted stimulation and pure steam stimulation. Test results show flue gas-foam assisted stimulation has outstanding advantages over pure steam stimulation for development of thin and heterogeneous heavy oil reservoirs because it may effectively enhance performances of steam stimulation. After optimization of the parameters for flue gas-foam assisted steam stimulation in Jinglouling Block, Henan Oilfield, the daily steam injection volume has been up to100 m3, gas/steam ratio to 12 and soaking time to 7 days.