Abstract: Cryogenically cooled and liquified energy gases are stored at substantial depth offshore in an insulated container normally resting on the seabed. Piston action of the container promotes liquid state of the liquified gases by transfer thereto of controlled pressure derived totally or in part from the ambient deep seawater.

Abstract: Improvements in an offshore platform and submarine storage facility for highly chilled liquified gas, such as liquified natural gas, are disclosed. The improved facility includes an elongated, vertically oriented submerged anchoring frame to which one or more insulated storage tanks are moveably mounted so they can be positioned at a selected depth in the water. The double piston tank is constructed with improved seals to transfer ambient water pressure of the selected depth to the cryogenic liquified gas without intermixture. This transferred pressure at the depth selected aids in maintaining the liquified state of the stored liquified gas. Structural improvements to the tank facilitating ballasting, locking the double piston cylinders together and further facilitating surface access to the tank for inspection, repairs and removal, and structural improvements to the platform are disclosed.

Abstract: An offshore submarine storage facility for highly chilled liquified gas, such as liquified natural gas, is disclosed. The facility includes an elongated, vertically oriented submerged frame. An insulated storage tank is movably mounted to the frame so as to be positionable at various depths in the water. The tank is constructed to transfer external ambient water pressure to the liquified gas without intermixture. This transferred pressure aids in maintaining the liquified state of the stored liquified gas.