Cyclic Hot Solvent Injection (CHSI) Process for Enhanced Heavy Oil Recovery in Thin Reservoirs

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One of the long-term goals of my research program is to develop effective and efficient techniques to unlock Western Canada's heavy oil resources in an environmentally sustainable way. Western Canada has the second largest oil resource in the world. Over 90% is heavy oil and bitumen. Among them, about 32 billion of heavy oil is deposited in Lloydminster area. The heavy oil reservoirs in Lloydminster are featured with thin pay-zone (in average 3-5 m thick), high oil saturation (average 85%), high permeability (average 2D), and high viscosity (1000 12,000 cp). Cold Heavy Oil Production with Sand (CHOPS) is the main recovery method in this area. However, only 10-15% of oil can be produced with CHOPS. Even though enhanced oil recovery method is strongly needed for Lloydminster heavy oil reservoir. None of current enhanced heavy oil recovery method is commercially viable. ******This research program is proposing a new hybrid process, Cyclic Hot Solvent Injection (CHSI) process and both fundamental and application studies will be conducted. The new invented CHSI process is a single well based process where heated solvent in its near dew point is employed as injection fluid. In each cyclic of the CHSI process, similar to CSI process there have three periods: solvent injection, soaking and production. The solvent used for CHSI process is propane or butane. The injected solvent can be heated to 50-100 C, depending on which solvent is used. The wellbore should be insulated in order to prevent heat loss through the well bore and condensation of solvent in the wellbore. During the injection and soaking periods, both heat and mass transfers occur in the reservoir. The latent heat and sensible heat carried by the solvent will be transferred to the reservoir/hydrocarbon system and solvent will dissolve into the heavy oil. The oil viscosity will be reduced due to the increased reservoir temperature and the dissolved solvent. In the oil production period, both pressure and temperature of the reservoir will be decreased gradually. Foamy oil flow, solution gas drive and gravity effects are the main driving mechanisms of the oil production. The CHSI process is a new process and has never been investigated by other researchers yet. During the past two years, through my NSERC Discovery Development Grant preliminary assessment of CHSI process has been conducted and promising results have been obtained. Patent application is in the process to protect the Intellectual Property of this invention. The proposed research program is to evaluate the performance of CHSI process, better understand the fundamental physics of CHSI process under different pressure and temperature effects and measure fundamental data which needed to evaluate the performance of this process in field scale.*****