A Comprehensive Study of Fluid Flow and Its Interactions within Porous Media in Steam-Assisted Gravity Drainage (SAGD) - Experimental and Simulation Studies
Date
2022-09
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Abstract
Since the invention of steam assisted gravity drainage (SAGD), numerous efforts have been made to explore and enhance the process. This work studies three previously overlooked parameters and the noteworthy effect they have on reservoir pressure and saturation distributions: the shape of the steam chamber, the thermal expansion of the fluids, and the creation of a hydrocarbon bank. The results show that neglecting to consider these yields an inaccurate description of pressure and saturation distributions. Most notably, the pressure gradient is generally positive (dP/dx>0) from the chamber edge into the mobile region, contrary to an alleged monotonic pressure gradient horizontally (with dP/dx<0) from the chamber edge toward the cold part of the reservoir. Secondly, a hydrocarbon bank barrier limits the horizontal condensate flow from the chamber edge to the cold region, contrary to previous assertions of a horizontal flow path from the chamber edge into the cold region due to the initial water mobility in the reservoir. Consequently, neither the initial water mobility nor the difference between the injection pressure and the reservoir pressure result in a notable horizontal convective heat transfer from the chamber edge to the cold reservoir. A variety of SAGD studies have reported the production of water-in-oil emulsions. A key question is whether the emulsions are generated in situ. Exploring potential causes for in situ emulsification in SAGD has been limited to steam condensation. No rigorous investigation has been done on the possibility of in situ emulsification during commingling flow of the bitumen and condensed steam toward the production well. To this end, a detailed experimental study was performed, focusing on the role of four parameters: the viscosities of wetting and non-wetting phases, the wettability of porous media, the phase containing emulsifier, and the flow rate ratio. The in situ emulsification – for both non-wet in wet and wet in non-wet type of emulsions – only occurs if the capillary number of the non-wetting fluid is equal or larger than 0.000036. The capillary number analyses suggest that water-in-oil emulsions are unlikely to be generated in the mobile region in SAGD.
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Keywords
SAGD, Emulsion, In Situ Emulsification, Flow Flow in Porous Media, Heat Transfer in SAGD
Citation
Kasraian, A. (2022). A comprehensive study of fluid flow and its interactions within porous media in steam-assisted gravity drainage (SAGD) - experimental and simulation studies (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.