Simulation of stability or failure of a combustion front during in-situ combustion in a Post-SAGD process

Autor: Xue Bai, Sihan Wu, Congning Yang, Norman Freitag, Na Jia
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Results in Engineering, Vol 16, Iss , Pp 100635- (2022)
Druh dokumentu: article
ISSN: 2590-1230
DOI: 10.1016/j.rineng.2022.100635
Popis: The highly viscous nature of heavy oil/bitumen in the Lloydminster area leads to difficulty for oil recovery and production. In-situ combustion (ISC) is an attractive candidate as a post-SAGD (steam assisted gravity drainage) operation to improve oil mobilization and maximize oil production. The objective of the study was to demonstrate that the stability or failure of a combustion front when in-situ combustion is implemented in a post-SAGD reservoir can be realistically simulated on the basis of a sound understanding of the underlying chemical reactions, whose rates and stoichiometry have been determined from laboratory measurements. This accomplishment represents a significant step towards an improved application of the in-situ combustion processes.The simulations were performed with the Computer Modelling Group's (CMG) commercial simulator STARS. Four dominant ISC chemical reactions (i.e., pyrolysis of non-volatile oil, low-temperature oxidation, pyrolysis of partially oxidized oil, and combustion) were developed on the basis of available experimental data. Material and energy balances were applied. A representative fluid properties package was obtained by tuning components' parameters to match with available vapor-liquid equilibrium data. ISC was initiated after the steam-assisted gravity drainage stage had been simulated. By successively reducing the simulated initial (pre-SAGD) oil saturation in steps, it was shown that the combustion front changed from stable propagation to being extinguished at a low initial oil saturation around 0.06, for which a combustion-front temperature of 400 °C was maintained. The residual oil saturation approached zero after combustion.
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