Techno-economic assessment of solvent-based bitumen extraction technologies including in-situ electromagnetic heating

Abstract

The oil sands are a vast fossil fuel resource that supports the worldwide energy supply. The bitumen found in fossil deposits is too viscous to flow under reservoir conditions. For this reason, steam-based processes such as steam-assisted gravity drainage (SAGD) are used to increase the reservoir temperature and allow the bitumen to flow. These processes have been successfully implemented. However, they are energy- and greenhouse gas (GHG) emission-intensive because a large amount of fossil fuels is burned to generate the steam. Methods of extraction using solvents are more promising technologies to lower the environmental impact of oil sands extraction. Solvent-based bitumen extraction technology as well effective solvent extraction incorporating electromagnetic heating (ESEIEH) technologies have been successfully tested on laboratory and pilot scale however there is very limited information on the comprehensive techno-economic assessment of bitumen produced from these technologies. This study conducts a techno-economic assessment of these technologies to understand the economic viability of these new processes. In this study, process models of solvent-based bitumen extraction and ESEIEH technologies were developed to evaluate their equipment size and energy requirement. The solvent purification unit was optimized with a high-temperature distillation column. The techno-economic models for solvent-based bitumen extraction and ESEIEH evaluate the supply cost of dilbit produced by these technologies. Considering the uncertainty in the results, the supply costs range from C$48.20/bbl to C$63.70/bbl and from C$55.20/bbl to C$64.40/bbl for the solvent-based extraction and ESEIEH technologies, respectively. The solvent loss in the reservoir is the parameter that most affects solvent-based bitumen extraction technology cost. For the ESEIEH process, the diluent and transportation costs were the major cost contributors. The application of shallow and deep reservoirs was also investigated. For both the bitumen extraction technologies, the use of butane for shallow reservoirs increased the supply cost slightly. The solvent purification unit in the solvent-based bitumen extraction process was modeled through two additional pathways. Pathway I uses a dehydration and refrigeration system to lower the solvent losses in the processing facility. Pathway II uses high-pressure separators to reduce the plant size and lower the impurities in the solvent. The supply costs increased by 5.8% and 2.9% from the base case in pathways I and II, respectively. The developed scale factors of the solvent-based extraction process and ESEIEH technologies are 0.72 and 0.85, respectively. These results suggest that at larger plant capacities, there is a cost benefit due to economies of scale. The results also show that the solvent-based extraction and ESEIEH processes are cost-competitive for oil prices above US$50/barrel. The findings of this study can assist policymakers and industry in decision-making regarding these new bitumen extraction technologies.