Research Progress and Outlook on the Mechanism of Non-Uniform Utilization in Supercritical CO₂ Flooding Development of Shale Reservoirs

Supercritical CO₂ flooding technology for shale reservoirs represents a key approach to achieving efficient, low-carbon development. However, its effectiveness is significantly constrained by reservoir heterogeneous mobilization phenomena. This paper aims to review research progress and future prospects in this field. Supercritical CO₂ enhances recovery rates through core mechanisms including viscosity reduction, expansion, extraction, and improvement of reservoir physicochemical properties. However, geological mechanical heterogeneity, complex fracture networks, and nanopore variations collectively induce non-uniformity in the mobilization process. Macroscopically, CO₂ tends to migrate along high-permeability zones and fractures, leaving distant matrix oil poorly mobilized. Microscopically, disparities in transport capacity between organic and inorganic pores, coupled with diffusion-seepage coupling mechanisms, create pore-scale mobilization imbalances. Current research integrates multi-scale approaches including physical experiments, numerical simulations, and field monitoring, yet challenges persist such as unclear multi-field coupling mechanisms and difficulties in in-situ nanoscale observation. Future studies should focus on deepening understanding of multi-physics coupling mechanisms, developing intelligent and precise predictive models, and exploring integrated enhancement technologies to advance balanced mobilization and commercial development of shale reservoirs.