The invention provides a method and a device for exploiting a deep-sea
natural gas hydrate. At present, the development of a
submarine natural gas hydrate is still at a starting stage; conventional methods of mechanical
fishing, mechanical extraction, hot water
perfusion, drilling platform collection and the like are used more frequently; the cost is higher; moreover, the instable
natural gas hydrate is easily enabled to excessively decompose; a
submarine topography is damaged; according to the method and the device for exploiting the deep-sea natural gas hydrate, on the basis of a hot water
perfusion method, a movable bell-mouth-shaped gas collecting hood group and a gas collecting
pipe network are arranged at the bottom of a sea; a leakage is prevented; the natural gas hydrate is gasified at a sea
bed through the approaches of a temperature rise, a
pressure reduction and the like; a
gas bubble is collected by a gas collecting hood to be directly led to an offshore platform or an island /
reef reservoir. A heat source for the temperature rise can come from the
waste heat of a factory on a coast or an island; meanwhile, the
submarine topography is protected by comprehensively utilizing the mill
tailings of a
solid mineral product for backfilling. The method and the device for exploiting the deep-sea natural gas hydrate have the advantages that energy sources are saved; the submarine
topography is protected, the
waste heat and a waste residue are comprehensively utilized.