Thermodynamic Modeling Analysis of Depressurization–Heating-InducedDissociation Paths on Hydrate Production Efficiency

The relationship between hydrate production efficiency and the temperature–pore pressure interaction pathway forms the basis for optimizing exploitation strategies. To analyze hydrate dissociation characteristics under different production pathways, this study derives the governing expressions for seepage rate and heat conduction within the framework of granular thermodynamics, which capture the promoting effects of temperature and pore pressure on multiphase flow. A thermal driving coefficient is further introduced to achieve coupling between the thermal and hydraulic fields. The effectiveness of the modified model is validated through hydrate dissociation simulations under depressurization and heating conditions. Furthermore, five production pathways are investigated, namely, depressurization, heating, depressurization followed by heating, heating followed by depressurization, and the combined depressurization–heating method. The results show that the depressurization followed by heating method weakens the inhibitory interaction between the temperature and pore pressure and achieves the highest production efficiency under pressures of 2–3 MPa and temperatures of 285–290 K. This study also reveals the competitive regulatory mechanism between heat conduction and the endothermic effect of hydrate dissociation, providing a theoretical basis for optimizing production strategies for marine natural gas hydrates.