Pore-scale analysis of steam-solvent coinjection: azeotropic temperature, dilution and asphaltene deposition. (15th May 2018)

• Record Type: Journal Article
• Authors: Xu, Lining; Abedini, Ali; Qi, ZhenBang; Kim, Mira; Guerrero, Adriana; Sinton, David
• Is Part Of: Fuel. Volume 220(2018)
• Page Start: 151
• Page End: 158
• Publication Date: 2018-05-15
• Subjects: Bitumen -- Steam -- Solvent -- Pore-scale -- Condensation -- Micromodel -- Microfluidics; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.01.119
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract: Steam assisted gravity drainage is the main technologically and economically feasible method for in situ bitumen extraction. However, SAGD is energy intensive with economic and environmental challenges. Steam-solvent coinjection has proposed to improve SAGD performance, where hydrocarbon solvent is simultaneously injected with steam to increase the production rate and lower the steam-oil-ratio. The addition of solvent, however, complicates an already complex multicomponent thermal-chemical process. Microfluidics is well suited to quantify the pore-scale of steam-solvent coinjection with a tight control over experimental parameters. In this study, a high-pressure high-temperature micromodel combined with optical and thermal imaging is used to probe the pore-scale of steam-solvent coinjection process at relevant reservoir conditions. The effects of butane and hexane, as well as two industrial solvents, condensate and naphtha, on the pore-scale mechanisms are quantified and compared. The in situ thermal data is used to profile and analyze the condensation zone behavior and steam-solvent azeotropic temperature for all steam-solvent cases. We find that overall performance depends on the difference between steam-solvent azeotropic temperature and steam saturation temperature, the degree of solvent-bitumen dilution, and the degree of asphaltene precipitation in the condensing zone. In contrast with pure solvents and condensate, naphtha results in the highest recovery due to a higher steam-solvent azeotropic temperature, effective dilution, with minimal asphaltene deposition.