Research prospects of key flow parameters evolution in hydrate-bearing sediments

Natural gas hydrate holds significant importance for the sustainable energy development in the future with high efficiency and enormous reserves. However, hydrate exploitation involves complex physical phenomena such as phase transition, mass transfer, deformation, gas expansion, and particle migration compared with conventional oil and gas reservoirs, resulting in spatiotemporal variations in key flow parameters including permeability, water retention curve, and gas-water relative permeability curve. Figuring out the evolution mechanisms of these key flow parameters is crucial for accurate prediction, strategies determination and adjustment of production in hydrate-bearing sediments. Although substantial research has been carried out, comprehensive review summarizing key flow parameters evolution remains scarce. Therefore, this work systematically summarizes the current research respectively from three aspects involving hydrate pore habit that primarily affects key flow parameters evolution, experimental and numerical methods for obtaining key flow parameters, and the representative models. Potential directions for future investigation are further proposed followed by challenges in this research area. This work provides a solid foundation towards the efficient and safe exploitation of natural gas hydrate.