Mathews, Tanya Ann Ann (2021-04). INVESTIGATION OF ENVIRONMENTALLY FRIENDLY SOLVENTS FOR THE RECOVERY OF HEAVY OIL AND BITUMEN. Master's Thesis.
Thesis
Solvent injection recovery processes were introduced as a more energy-efficient and environmentally friendly alternative to Steam injection processes. However, BTX chemicals commonly used for crude oil recovery due to their strong solvency and low asphaltene precipitation are acutely toxic and harmful to the environment. These chemicals are easily soluble in water causing groundwater contamination. In this study, I test the effectiveness of three solvents; Visred, Limonene and Pinene and compare their results to conventional toxic solvents. Visred, although toxic, is chosen as a solvent as it can reduce the amount of solvent injected into the wellbore. Limonene and Pinene are environmentally friendly non-toxic edible solvents. These are also readily available and cheaper than conventional solvents. Three crude samples have been tested in this study: Canadian Bitumen, Californian heavy oil (Cali 1) and Californian extra heavy oil (Cali2). A total of 15 core flooding experiments including both steam and steam-solvent flooding processes were conducted and the best recovery method for each crude sample was determined based on produced oil quality, displacement efficiency, oil recovered and economic parameters. This work proves the effectiveness of these solvents in yielding comparable if not more oil recovery than conventional solvents and can be instrumental to heavy oil and bitumen resources across the globe.
