A novel dual-network CO2-responsive particle gel for mitigating CO2 channeling and leakage in hydrocarbon recovery and carbon storage

• A novel dual-network CO 2 -responsive particle gel is developed to mitigate CO 2 channeling/leakage. • An in-situ self-reinforcement behavior in plugging ability of the new gel is observed. • CO 2 -repsonsiveness enables a favorably higher resistance to CO 2 than that to water. • Remarkable oil recovery improvement potential is experimentally demonstrated. In this work, we developed and systematically evaluated a novel dual-network CO 2 -responsive preformed particle gel (DN-CRPPG) to address CO 2 channeling and leakage in hydrocarbon recovery and carbon sequestration. The work was proven an effective effort to overcome the insufficiency of traditional channeling-control chemicals due to severe dehydration and degradation in contact with CO 2 . We focused on placement and plugging behavior of the DN-CRPPG in fractured reservoirs under various circumstances. Results of high-pressure vessel test show that DN-CRPPG expanded further when exposed to supercritical CO 2 . The responsive swelling ability was enhanced with the increase of pressure. Core flooding and plugging experiments show significantly improved CO 2 -channeling control ability compared with traditional non-responsive particle gels. Three key mechanisms were observed to be responsible for the improved performance. First, the CO 2 -responsive behavior resulted in volume swelling of DN-CRPPG. Therefore, the void spaces among the particles were occupied by the swelled gel particles, making the DN-CRPPG exhibit an in-situ self-reinforcement behavior in plugging ability. Second, the dual network structure with a relatively rigid network and a more flexible one enhances its mechanical ability and resistance to CO 2 flush. Third, the CO 2 -repsonsiveness enabled the new gel a remarkably higher resistance to CO 2 than that to water, while traditional gel is the opposite. This behavior is favorable for balancing the mobility of CO 2 and water as the fact that CO 2 itself is much more mobile due to low viscosities. Significant CO 2 breakthrough mitigation and oil recovery improvement were demonstrated after treatment with the new gel (>30 %). This work is supposed to provide guidance for improving the success of hydrocarbon recovery and carbon storage by more effectively mitigating CO 2 channeling and leakage.