A sealed and insulating reservoir contains a pressurized cold fluid in a rigid, sealed enclosure. A fluidtight membrane is positioned to contact the cold fluid contained in the reservoir. An insulating barrier is placed between the fluidtight membrane and the internal surface of the rigid enclosure, with the insulating barrier forming a support surface to support the fluidtight membrane. A pressure balancing device is able to limit the pressure difference between a first sealed volume located inside the fluidtight membrane, and a second sealed volume located outside the fluidtight membrane. The pressure balancing device typically includes a fluid circuit having two chambers sealingly separated by a movable separator. The first chamber is linked to the first sealed volume, and the second chamber is linked to the second sealed volume. The movable separator exerts a loading force in the direction of the second chamber.

A storage container includes a wall structure defining an interior, where the interior is configured to contain a fluid. A portion of the wall structure is formed by a composite material. The composite material includes frozen water and a fibrous additive.

A sealed and insulating tank for storing and/or transporting a liquefied gas has a sealed and self-supporting internal reservoir with an interior surface for contacting the liquefied gas and an outer surface with an insulating barrier covering the outer surface of the internal reservoir. The insulating barrier is fixed to the internal reservoir. An outer sealed membrane covers an outer surface of the insulating barrier, and the outer sealed membrane has a metal sheet provided with bellows or corrugations. The outer sealed membrane is fixed to the insulating barrier or the internal reservoir. An intermediate space between the internal reservoir and the outer sealed membrane contains a gaseous phase under depression in order to press the outer sealed membrane against the outer surface of the insulating barrier.

A sealed and insulating tank for storing and/or transporting a liquefied gas has a sealed and self-supporting internal reservoir with an interior surface for contacting the liquefied gas and an outer surface with an insulating barrier covering the outer surface of the internal reservoir. The insulating barrier is fixed to the internal reservoir. An outer sealed membrane covers an outer surface of the insulating barrier, and the outer sealed membrane has a metal sheet provided with bellows or corrugations. The outer sealed membrane is fixed to the insulating barrier or the internal reservoir. An intermediate space between the internal reservoir and the outer sealed membrane contains a gaseous phase under depression in order to press the outer sealed membrane against the outer surface of the insulating barrier.

The present invention relates to a subsea storage system for storing a water miscible storage fluid and methods related thereto.