A novel dual-network CO2-responsive particle gel for mitigating CO2 channeling and leakage in hydrocarbon recovery and carbon storage
Yang Zhao, Xin Wen, Zhenhua Rui, Yanxu Ding
Abstract
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.