Experimental Study of Effect of Initial Mobile Water Saturation on Solvent Mixing with Bitumen in ES-SAGD
Maini, B. B.
Committee MemberHassanzadeh, Hassan
Shor, Roman J.
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AbstractSteam-assisted gravity drainage (SAGD) is a commercially successful enhanced oil recovery technology. However, the process is energy intensive. One way to reduce the energy cost is through adding solvent in the vapor phase. In solvent-based processes, like Expand-solvent steam assisted gravity drainage (ES-SAGD), the mixing of a solvent and bitumen at the chamber edge warrantsinvestigation. Given that initial water is often mobile in the reservoir, it is important to examine its effect on solvent transportation and mixing with bitumen. The study aims to evaluate the effect that different initial mobile water saturations have in solvent-bitumen mixing. Varying mobile water saturations were generated in linear sand-packs to experimentally examine how mobile water affects the propagation of solvent in the bitumen zone. Solvent was injected into sand-packs containing a small mobile water saturation at slow rates. The pressure drop was recorded; the produced fluid was collected and analyzed. Experimental and simulation results show that the solvent fingers through the bitumen zone by displacing part of the mobile water saturation and appears at the production end very quickly. The bitumen content in the produced fluid sample was found to be small, decreasing during the progress of the flooding. This suggests that the solvent fingers became thicker by leaching out the bitumen. Such a rapid penetration of solvent in the bitumen zone, as a result of displacing mobile water, can greatly enhance solvent-bitumen mixing. Therefore, mixing solvent with bitumen in solvent-based processes needs to be modeled as a two-dimensional convection-diffusion process, instead of the diffusion/dispersion model that has been frequently reported in literature.
Schulich School of Engineering