A 3-D Physical Model Experimental Study of the ES-SAGD Process Utilizing Dimethyl Ether (DME) as a Solvent

Steam-assisted gravity drainage (SAGD) is a widely used method in the oil sands industry for recovering bitumen. However, it faces several challenges, such as high energy consumption, significant heat loss, and the emission of harmful gases that are detrimental to the environment. Hence, the introduction of Expanding Solvent-SAGD (ES-SAGD) combines the advantages of solvent and heat to help curtail these challenges while improving the process’s efficiency. In this work, we conducted three-dimensional physical model experiments (3DPMEs) of ES-SAGD using dimethyl ether (DME) as a solvent compared to a baseline conventional SAGD. The recovery factor, oil rate, water cut, cumulative gas production and composition, cumulative steam-oil ratio (SOR), gas-oil ratio (GOR), and energy reduction and carbon tax analysis are essential factors analyzed in this work. The result shows that coinjecting DME at low concentrations with steam significantly improves bitumen recovery rates compared to the baseline SAGD process. Furthermore, the average steam-oil ratio (SOR) as a measure of energy efficiency reduces from 9.4 for the conventional SAGD to 3.7, 2.14, and 4.3, representing a 60%, 77%, and 54% reduction for 1.25, 2, and 3 mol % DME in ES-SAGD, respectively. Additionally, the study reveals that the cumulative GOR generally increases as the solvent concentration increases. This study demonstrates that incorporating DME as a solvent compared to hydrocarbon solvents in the solvent-assisted thermal recovery process can significantly reduce the environmental impact of the oil sands sector. With a 47–69% reduction in CO2 emissions, a lower steam-oil ratio, and greater carbon tax recovery, ES-SAGD using DME enhances energy efficiency, minimizes greenhouse gas emissions, and accelerates the transition to a low-carbon economy while improving overall sustainability in bitumen recovery compared to natural gas condensates.