Method and system for offshore production of liquefied natural gas

A method for offshore production of liquefied natural gas comprising the steps of:

• a) supplying a natural gas from an underground source to a subsea production plant;
• b) providing and securing a pipeline formed of a material capable of heat transfer between said production plant and a submerged buoy provided with a swivel unit for transferring gas under high pressure, said buoy being capable of being introduced and releasably secured in a submerged downwardly open receiving space in an LNG tanker;
• c) securing said buoy to said LNG tanker;
• d) transferring said gas under a high pressure from the production plant to the LNG tanker through the pipeline surrounded by sea water, wherein the transferring step includes the steps of:
• (i) supplying said gas directly from the production plant to the pipeline at a relatively high temperature;
• ii) cooling said gas in said pipeline to a desired low temperature near the temperature of the sea water by heat exchange with the sea water surrounding the pipeline;
• and
• iii) supplying the gas to a conversion plant provided on the LNG tanker;
• e) expanding and converting at least a portion of the gas within the conversion plant to a liquefied form;
• f) transferring the liquefied gas to storage tanks on board the LNG tanker;
• and
• g) disconnecting the pipeline from the LNG tanker when the storage tanks on the tanker are filled.