The gas transport in shale nanopores is always one of the major concerns in terms of the development of shale gas reservoirs. In this study, the gas flow regimes in shale nanopores were classified and analyzed according to Knudsen number. Then the gas flow model considering Darcy flow, slip flow, transition flow, molecular free flow and adsorption effect was proposed to evaluate the gas flow behavior in shale nanopores. The result shows that the contributions of Darcy flow, slip flow and transition flow in shale nanopores are reciprocal, and are mainly dominated by pore radius and pressure. The adsorption effect greatly influences the total mass flux. The total mass flux will increase as Langmuir pressure and temperature increase while it will decrease with reservoir pressure and the adsorption thickness. These results can provide insights for a better understanding of gas flow in the shale nanopores so as to optimize the production performance of shale gas reservoirs.

Fractured bottom-water gas reservoirs are prone to water channeling during production, leading to gas well flooding and reduced recovery. This study takes the B9 gas reservoir in the Tarim Basin as the research object and employs numerical simulation methods to conduct collaborative optimization research on early water invasion prevention and CO₂ injection for enhanced recovery. Firstly, reasonable gas production rates and water-avoidance heights are optimized to determine the optimal development scheme. Then, the CO₂ injection location and rate are systematically optimized to establish the optimal injection scheme. The research results indicate that the highest recovery factor of 32.3% is achieved when the field production rate is 2%, the water-avoidance height is 80 m, gas injection is performed at the water invasion front, and the injection rate is 15 × 10⁴ m³/d. Under this optimal scheme, the CO₂ storage volume reaches 585.6 × 10⁶ m³, with a storage ratio of 44.2%, of which dissolved storage accounts for 24.5 × 10⁶ m³ and structural storage accounts for 561.1 × 10⁶ m³. The research findings provide a technical reference for the synergistic development of early water invasion prevention and CO₂ injection for enhanced recovery and storage in fractured bottom-water gas reservoirs.