| Solvent injection at elevated temperatures (hot solvent or steam-solvent hybrid injection) into heavy-oil/bitumen reservoirs is a promising recovery process. It increases oil mobility via oil dilution, molecular diffusion, and gravity drainage. Meanwhile, injection of light hydrocarbon solvents creates disequilibrium between resins and asphaltene in the oil. Then, asphaltene starts to flocculate and bond to each other in the fluid and on the rock surface. Consequently, permeability reduction due to pore plugging and wettability alteration may take place affecting the underground upgrading and recovery process negatively.;In this thesis, these asphaltene related concerns during solvent injection at different reservoir conditions were investigated through experimental work. A combination of two heavy-oil compositions and four solvent types were tested at different pressure and temperatures to determine the optimal solvent type and operational conditions minimizing the negative effect of asphaltene. The results obtained from visual PVT cell (testing fluid behaviour) and sandpack system (testing heavy-oil recovery) experiments were cross-checked. The roles of solvent type and operation conditions (mainly temperature) on the heavy-oil recovery, wettability alteration, and pore plugging were clarified and presented quantitatively and visually. |
