Investigation of gas hydrate production with salinity via depressurization and thermal stimulation methods

Natural gas resources trapped in hydrate reserves worldwide are a new substitute for conventional energy. To safely and efficiently extract natural gas from hydrates, fields test and laboratory investigations were systematically conducted. Salinity is a significant factor impacting the exploitation of the marine hydrates. In this study, a two-dimensional cylindrical model was developed to determine the influences of salinity on gas recovery induced by depressurization and thermal stimulation. The results indicated that, with the same exploitation method, higher salinity accelerated the pressure-drop propagation rate and temperature increment spread, thereby promoting the hydrate dissociation rate and shortening the gas production process. Furthermore, thermal stimulation improved the average gas generation rate by almost five times that with depressurization at the same salinity.