Methane hydrate (MH) is considered as one of the most promising clean energy. In this study, the effects of overlying water on the formation and dissociation of MHs in sediments were analyzed. The results indicate that the overlying water can provide the sufficient water source and the driving force for hydrate formation. The time required to synthesize hydrate sample with high saturation (44.1%) is effectively shortened. Additionally, the overlying water contributes to the heat and mass transfer, thereby promoting the hydrate dissociation and the gas-water production during depressurization. The findings of this study could pave the way for the utilization of overlying water to enhance the gas production efficiency for marine hydrate exploitation.
Keywords methane hydrate, overlying water, dissociation, sediment, depressurization