Performance Evaluation of Hybrid Steam-Solvent Processes in A Post-CHOPS Reservoir with Consideration of Wormhole Network

In this paper, techniques have been developed to evaluate performance of steam, solvents, and hybrid steam-solvent processes in a post-CHOPS reservoir with consideration of wormhole network. With the experimentally determined properties of injected gases and reservoir fluids, history matching is accomplished for the reservoir geological model conditioned to the fluid and sand production profiles together with pressure. Meanwhile, the wormhole network is characterized with the pressure-gradient-based (PGB) sand failure criterion. Once the history matching is finished, the calibrated reservoir geological model can be employed to quantify the contributions of steam, solvents, and hybrid steam-solvent processes under various conditions. The results show that huff-n-puff processes have a very good performance on oil production and recovery when wormhole network is fully generated and propagated. Among all the solvent-based methods, a pure CO2 huff-n-puff process has been proven to be more efficient than flue gas, while the addition of alkane solvents is also beneficial to oil recovery compared with CO2 only method. Since the addition of C3H8 and n-C4H10 will significantly decrease the heavy oil viscosity and enhance the swelling factor, all hybrid steam-solvent injection achieves high oil recovery by taking the advantage of both hot steam and solvents injection.

Performance Evaluation of Hybrid Thermal-Solvent Injection in a Post-CHOPS Reservoir With Consideration of Wormhole Network

In this paper, techniques have been developed to evaluate performance of thermal, solvents, and hybrid thermal-solvent processes in a post-CHOPS reservoir with consideration of wormhole network. With the experimentally determined properties of injected gases and reservoir fluids, history matching is accomplished for the reservoir geological model conditioned to the fluid and sand production profiles together with pressure. Meanwhile, the wormhole network is characterized with the newly developed pressure-gradient-based (PGB) sand failure criterion. Once the history matching is completed, the calibrated reservoir geological model is then employed to evaluate performance of thermal, solvents, and hybrid thermal-solvent processes under various conditions. It is found that huff-n-puff processes have a very good performance on enhancing oil recovery when wormhole network is fully generated and propagated. Among all solvent-based methods, pure CO2 huff-n-puff process shows a better performance than flue gas, while the addition of alkane solvents leads to a higher oil recovery compared with CO2 only method. Since the addition of C3H8 and n-C4H10 will significantly decrease the heavy oil viscosity and enhance the swelling factor, all hybrid thermal-solvent injection achieves high oil recovery by taking the advantage of both hot steam and solvents injection.