Performance Evaluation of Hybrid Steam-Solvent Processes in a Post-CHOPS Reservoir With Consideration of Wormhole Network

摘要

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 used 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.