Comparative Study of Thermal and Mechanical Heating Methods for Heavy Oil Recovery

Heavy oil recovery is challenging owing to the high viscosity and low mobility of the oil, necessitating the application of modern recovery technologies. This paper presents a detailed comparative study of the four most widely used recovery processes: Cyclic Steam Stimulation (CSS)/Steam Flooding, Steam-Assisted Gravity Drainage (SAGD), In-Situ Combustion (ISC), and THOR Cavitas (mechanical heating system). The qualitative and quantitative comparisons show the relative merits and demerits of the four processes. SAGD has the maximum recovery efficiency (60-70%) for heavy oil in thick, homogeneous reservoirs, while CSS has a moderate recovery (25-30%), with high energy requirements (500-1000 MJ/bbl) and water requirements (2-5 bbl of water per barrel of oil). ISC has the highest energy efficiency (50-60%) and low water requirements (0.5-1.5 barrels of water per barrel of oil), but it has issues with combustion control. THOR Cavitas has high recovery efficiency (50-60%) by mechanically generating heat directly inside the wellbore with water requirements and reduced greenhouse gas emissions, and has significantly lower capital costs when compared with steam-based facilities. CSS and steam flooding are mature and flexible technologies, but are environmentally taxing. While SAGD is good at continuous operation but is limited to certain reservoirs, and ISC utilizes in-situ energy but needs precise operational control. THOR Cavitas is unique in that it is a selective direct contact heating method with environmental advantages, but it is a less mature technology. From the results, we can gather data that can help us in selecting certain techniques, including hybrids and new technology such as THOR Cavitas, which can assist us in recovering heavy oil in an environmentally friendly manner.