Experimental and Numerical Simulation Studies of Cyclic Solvent Injection (CSI) Coupled with Hot-Water Injection and Electro-Thermal Heating in Post CHOPS Reservoirs

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Cold heavy oil production with sand (CHOPS) involves the continuous flow of heavy oil together with an influx of sand to enhance oil production rates. The achieved recovery rates are low which leaves a significant amount of unrecovered heavy oil in post CHOPS reservoirs. Solvent-based enhanced oil recovery (EOR) processes such as cyclic solvent injection (CSI), co-injection of hot water and solvent as well as the combination of solvent injection with electro-resistivity heating are among the most promising techniques to enhance production in post CHOPS reservoirs. The successful application of such EOR processes requires a more detailed knowledge of recovery mechanisms and affecting reservoir and operational parameters. It is the objective of this research proposal to investigate the application of CSI and co-injection of hot water (HW-CSI) as well as in-situ heating through the utilization of electro-thermal methods (i.e. electro-resistivity) combined with solvents (ER-CSI) for post CHOPS reservoirs. More specifically, the effects of reservoir rocks and fluid properties such as reservoir permeability, wormhole length and configuration, and heavy oil viscosity will be studied. In addition effects of operating parameters including solvent type, injection pressure, slug size, length and duration of each injection cycle for CSI will be analyzed. Furthermore, the possibility of wormhole collapse, its effects, and potential prevention and remediation strategies for CSI and co-injection of hot water and solvent as well as combination of solvent injection with electro-thermal heating will be thoroughly investigated. A novel mathematical model will be developed to consider the dynamic changes in fluid and rock properties, foamy oil flow as well as the growth of wormholes. The effects of asphaltene precipitation on foamy oil behavior as well the overall performance of the processes will be also experimentally studied. Finally, CMG’s STARS will be used to simulate lab-scale processes for CSI, co-injection of hot water and solvent and combination of solvent injection and electro-resistance heating. The simulation model will be history matched with the experimental results and used to evaluate the effects of other parameters such as various well configurations and permeability anisotropy. A combination of the results obtained from experimental studies with those from numerical simulation will lead the researchers involved in this study to provide a more accurate numerical simulation model that can predict the performance of the CSI combined with hot-water and/or in-situ heating in post CHOPS reservoirs more precisely and while mapping the properties of the wormholes generated during the process. Such a model allows the researchers, and industry engineers to optimize the operating conditions to maximize the performance of CSI.