Evaluation of Methane Leakage during Marine Gas Hydrate Production by Depressurization and Hot Water Injection

Methane hydrate, a potential clean fuel with vast resources, has attracted significant global attention for its exploitation. However, concerns about methane leakage during the hydrate production process persist. This study aims to investigate the possibility of methane leakage during hydrate exploitation using the depressurization and hot water injection methods, as assessed through numerical simulation. Simulation results indicate that, when the depressurization method is employed, dissociated methane remains confined within the hydrate-bearing layer as a result of the pressure differential between this layer and the adjacent layers. Conversely, during hot water injection, the dissociated methane gas migrates into the overlying layer, driven by the increased reservoir pressure. Consequently, the depressurization method proves to be more environmentally friendly than the hot water injection method in terms of mitigating methane leakage.