Development of alkane solvents enhanced steam + flue gas processes for enhancing heavy oil recovery from post-CHOPS reservoirs

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As for the enormous heavy oil reserves deposited in Western Canada, the most common production process is the cold heavy oil production with sand (CHOPS) which can typically recover only 5-15% of original-oil-in- place due to both wormhole generation and foamy oil flow. As such, efficient follow-up enhanced oil recovery (EOR) techniques are required in these post-CHOPS reservoirs where both conventional steam-based thermal recovery techniques and solvent-based non-thermal recovery techniques find their limits. In practice, flue gas that typically consists of 80-88% N2 and 12-20% CO2 can be used as an efficient immiscible agent for enhancing heavy oil recovery through a free gas mechanism provided by N2 and a solubilization mechanism provided by CO2. The overall objective of this proposed research is to not only investigate the suitability and applicability for enhancing heavy oil recovery from the post-CHOPS reservoirs through the alkane/water-soluble solvents enhanced steam + flue gas recovery processes while minimizing environmental footprint, but also evaluate the possibility of safely storing CO2 in the depleted geological formations.With the successful development of direct contact steam generation (DCSG) processes referred to as the submerged combustion vaporizers (SCVs), this allows directly converting the untreated oilfield produced water into high-quality steam together with clean flue gas at high efficiency and low cost. With addition of alkane/water-soluble solvents, the newly proposed flue gas-assisted thermal recovery techniques with the optimized SCV operating parameters will be extended to the pilot tests in the targeted post-CHOPS reservoirs. The proposed research has the potential of providing the upstream oil and gas industry with viable techniques for efficiently and effectively recovering heavy oil from post-CHOPS reservoirs by taking advantages of both flue gas and thermal energy while minimizing freshwater usage as well as mitigating CH4 and CO2 emissions. This will also help Canada to become a technology resource centre, focusing on the usage of flue gases, EOR techniques for heavy oil reservoirs, and CO2 storage.