MULTI-FIELD COUPLING MODES DURING MARINE NATURAL GAS HYDRATE EXPLOITATION AND ITS ADVANCEMENTS

Marine natural gas hydrate(NGH) is widely accepted to be a promising clean energy resource, and its safe and effective production is of great significance. However, the marine NGH reservoirs are usually characterized by non-diagenesis, extremely weak consolidation, and shallow burial. The reservoir is faced with a strong multi-field coupling state during the extraction of natural gas from NGH reservoirs. Uncovering these multi-field coupling mechanisms is essential for productivity prediction, risk prediction, and control. The current study proposed a fundamental multi-field coupling mode, considering the geological background of the NGH reservoirs in the South China Sea and the geological background of depressurization. A comprehensive review of NGH phase change and mass transfer, heat transfer, reservoir deformation, and multi-field coupling methods is conducted. Special emphasis was focused on the necessity and importance of incorporating solid transfer and reservoir deformation processes during multi-phase analyses. Finally, main bottlenecks and possible outbreak perspectives were discussed. The results might provide some significance for engineering-geological-environmental integrated field operations for sustainable marine NGH development.