Effect of injection strategies on carbon dioxide storage in formations with different dip angles

Studying the differences in CO 2 migration distribution and stable storage mass between injection strategies in different inclined strata is crucial to optimizing implementation of Carbon Capture and Storage (CCS) projects. At present, the effects of injection strategy and formation inclination on CO 2 storage have not been considered simultaneously, and further research is needed. This study relies on CO 2 storage experiments in typical saline aquifers in the sedimentary plains and construct a three-dimensional numerical model to evaluate changes in reservoir pressure, CO 2 spatial distribution, and dissolved phase CO 2 storage quality under different inclination angles and injection strategies. The results show that both simultaneous-water-and-gas (SWAG) and water-alternating-gas (WAG) injection strategies significantly reduce the migration distance of CO 2 in the inclined formation, but both of them have a greater effect on the reservoir pressure than the continuous injection and intermittent injection strategies. The increase in formation inclination reduces the impact of different injection strategies on the stable storage volume, while the synergistic effect of the inclined formation and water injection strategy significantly reduces the CO 2 saturation and migration distance and accelerates the dissolution rate. This study provides ideas and engineering practice references for the selection of storage sites in different inclined formations.