Gas Hydrate Harvesting

Abstract

A harvester ( 10 ) with warm water spray jets ( 11 ) that fluidizes and releases gas hydrates from seafloor sand and soil. The released gas hydrates float into the harvester ( 10 ) and are then transferred through a hydrate slurry pipe ( 14 ) to a separation vessel ( 18 ). Dissociation of the gas hydrates into methane gas occurs in the separation vessel ( 18 ) from its lower pressure than the seafloor and the optional use of heat. The liberated methane gas flows upward in a gas vent pipe ( 27 ) to a topside vessel ( 30 ) for storage from the pressure of the submerged separation vessel ( 18 ). Alternatively, the vent pipe can be fed directly into an available natural gas pipeline. Crude oil collected in the separation vessel ( 18 ) can be separated and pumped to a topside vessel ( 30 ) for storage and use in a refinery. No other processing is required to produce commercial quality natural gas harvested directly from gas hydrates on or near the seafloor.

1 . A method of recovering a methane gas from a solid gas hydrate in a seafloor sand or soil comprising:
 a. placing a high pressure warm water spray jet at a specific location on the seafloor to fluidize said seafloor sand and soil;   b. placing a harvester above said high pressure warm water spray jet to capture said solid gas hydrate floating upward due to buoyant forces from the fluidization of said seafloor sand and soil;   c. transferring. said solid gas hydrate from said harvester through a hydrate slurry pipe to a separation vessel to dissociate said solid gas hydrate into said methane gas from localized depressurization of said separation vessel.   
     
     
         2 . The method of  claim 1  wherein said methane gas from said separation vessel is vented to a topside vessel through a gas vent pipe for storage and use as a natural gas. 
     
     
         3 . The method of  claim 1  wherein said methane gas is vented directly into a natural gas pipeline. 
     
     
         4 . The method of  claim 1  wherein said solid gas hydrate is transported to said separation vessel using a hydrate slurry pump. 
     
     
         5 . The method of  claim 1  wherein the separation vessel is heated. 
     
     
         6 . The method of  claim 1  wherein a crude oil is separated as a separate liquid phase in said separation vessel and pumped to said topside vessel through a crude oil pipe for storage and transportation to a crude oil refinery. 
     
     
         7 . An apparatus for recovering said methane gas from said solid gas hydrate in said seafloor sand or soil comprising:
 a. placing said high pressure warm water spray jet at a specific location on said seafloor to fluidize said seafloor sand and soil;   b. placing said harvester above said high pressure warm water spray jet to capture said solid gas hydrate floating upward due to buoyant forces from the fluidization of said seafloor sand and soil;   c. transferring said solid gas hydrate from said harvester through said hydrate slurry pipe to said separation vessel to dissociate said solid gas hydrate into said methane gas from localized depressurization of said separation vessel.   
     
     
         8 . The apparatus of  claim 1  wherein said methane gas from said separation vessel is vented to said topside vessel through said gas vent pipe for storage and use as said natural gas. 
     
     
         9 . The apparatus of  claim 1  wherein said methane gas is vented directly into said natural gas pipeline. 
     
     
         10 . The apparatus of  claim 1  wherein said solid gas hydrate is transported to said separation vessel using said hydrate slurry pump. 
     
     
         11 . The apparatus of  claim 1  wherein said separation vessel is heated. 
     
     
         12 . The apparatus of  claim 1  wherein said crude oil is separated as said separate liquid phase in said separation vessel and pumped to said topside vessel through said crude oil pipe for storage and transportation to said crude oil refinery.