Experimental and Numerical Studies of Foamy Oil Displacement Mechanisms in Heavy Oil Reservoirs
Date
2019-04-25
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Abstract
Foamy oil behavior has proven effective for heavy oil recovery and typically generates as pressure depletes in the first recovery stage. It possesses a low gas-oil ratio, maintains reservoir pressure and leads to high production recovery. Because the energy exhausts at the end of the first recovery stage, a significant amount of heavy oil remains underground. Therefore, the research objective is to develop a feasible gas injection process for foamy oil generation by understanding the generation mechanisms between gas and heavy oil. In the research, the mechanisms of foamy oil generation are experimentally investigated and the gas injection process is optimized. First, a vertical visible slab model is built, which can observe foamy oil generated in a gas flow channel. Gas injection tests are conducted afterwards. The strategy is optimized by identifying key parameters including gas injection type, gas injection rate, gas injection pressure and contact time. The model and our experiments reveal the mechanisms of foamy oil generation: the gas slowly reacts with the heavy oil at the contact surface and the generated foamy oil is stripped away with continuous gas injection. The highest oil recovery factor of 37.36% can be obtained by injecting gas at the rate of 2.0 ml/min, under 4.5 MPa, and using a contact time of 4 hours. The injected gas is mixed with 30% CH4 (methane) and 70% CO2 (carbon dioxide). Numerical simulation is also employed to validate the feasibility of the gas injection method for generating foamy oil and enhancing recovery in heavy oil reservoirs.
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Keywords
Foamy Oil, Gas Flooding, Reservoir Simulation
Citation
Wang, D. (2019). Experimental and numerical studies of foamy oil displacement mechanisms in heavy oil reservoirs (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.