A technical, economic, and environmental assessment on dimethyl ether (DME) as a renewable solvent from carbon dioxide utilization (CCU) for heavy oil recovery: A real field in Surmont, Canada as case study

Abstract

The Paris Agreement represents a shared global goal to combat climate change; however, national carbon emissions vary significantly, mainly due to heavy oil production. The viscous nature of heavy oil requires heat to make it flow, which significantly contributes to emissions. Addressing this issue and finding ways to produce heavy oil in a low-carbon manner while ensuring a win–win situation for economic and energy demands are challenges. If these challenges are successfully addressed, carbon emissions could be significantly reduced in countries that have abundant heavy oil resources. In this study, dimethyl ether is proposed as a renewable solvent from syngas, and we evaluate its technical, environmental, and economic performance through laboratory experiments and numerical simulations by taking the Surmont field in Canada as a case study. Our findings are as follows: a) through in-house experiments, DME solvent expanding steam-assisted gravity drainage outperforms conventional steam-assisted gravity drainage in terms of both a recovery factor and a maximum oil rate, with increases of 24% and over two times, respectively; b) from field-scale numerical simulations, DME co-injection with steam offers over two times the maximum recovery rate increase, an 80% reduction in a steam-oil ratio, an extra 50% increase in cumulative recovery, and 86% energy savings; c) the DME recovery rate can be increased by 13% compared to conventional solvents; d) a 0.06 reduction in DME's hold-up ratio and a 13% increase in the recovery ratio suggest that it has higher solvent efficiency and lower solvent losses than conventional light solvents (propane and butane); e) DME can, in theory, be produced with zero emissions; and f) DME demonstrates high economic robustness when considering fluctuating oil prices and carbon policies. In summary, this study demonstrates the potential benefits and applicability of DME-based processes in terms of technical, environmental, and economic aspects.