An installation for the in-port storage of liquid fuel, which is formed near a dock, is formed of at least an upper surface substantially parallel to the free surface of the sea and a frontal surface adjacent to the upper surface and partially immersed. The installation includes at least one module having a floating caisson containing a fluidtight tank that may contain liquid fuel and having a closed contour formed of an upper face, a lower face, and several lateral faces. The module is fixed to the dock by anchoring means connecting one of the lateral faces of the caisson to the frontal surface of the dock, the lower face and the lateral faces of the caisson therefore being at least partially immersed.

A subsea tank element comprises at least one tank section (1), the tank section(s) forming a cylindrical concrete-tank (2) closed at its opposite ends by two end caps (12). The tank element further comprises a rectangular structure (3, 4, 5) surrounding the cylindrical tank (2), and a connection (150, 160) between the rectangular structure (3, 4, 5) and the cylindrical tank (2) permitting a motion of the wall of the cylindrical tank (2) within predetermined limits for deflection of the rectangular structure (3, 4, 5). Permanent ballast (6, 7) and a ballast tank (8) control buoyancy and ensure static stability. Post tensioning cables through channels 9 tie the parts into a tank element, and the tank elements into a system. Several applications, including a subsea barge, a subsea hydro-electric plant and a hovering storage tank assembly are disclosed.

A subsea tank element comprises at least one tank section (1), the tank section(s) forming a cylindrical concrete-tank (2) closed at its opposite ends by two end caps (12). The tank element further comprises a rectangular structure (3, 4, 5) surrounding the cylindrical tank (2), and a connection (150, 160) between the rectangular structure (3, 4, 5) and the cylindrical tank (2) permitting a motion of the wall of the cylindrical tank (2) within predetermined limits for deflection of the rectangular structure (3, 4, 5). Permanent ballast (6, 7) and a ballast tank (8) control buoyancy and ensure static stability. Post tensioning cables through channels 9 tie the parts into a tank element, and the tank elements into a system. Several applications, including a subsea barge, a subsea hydro-electric plant and a hovering storage tank assembly are disclosed.

Apparatus and method for managing water or other ballast fluid in an underwater storage tank (14), used for storing fluids such as oil or CO2, where a dis-connectable inflatable bag (16) is coupled to the underwater storage tank to capture displaced ballast fluid from the underwater storage tank. A supply line (36) between the bag and tank provides a closed loop system. Embodiments are shown in which the tank is initially filled with fresh water and multiple dis-connectable inflatable bags are used.

Apparatus and method for managing water or other ballast fluid in an underwater storage tank (14), used for storing fluids such as oil or CO2, where a dis-connectable inflatable bag (16) is coupled to the underwater storage tank to capture displaced ballast fluid from the underwater storage tank. A supply line (36) between the bag and tank provides a closed loop system. Embodiments are shown in which the tank is initially filled with fresh water and multiple dis-connectable inflatable bags are used.

A floatable structure in particular a floatable platform including at least two separate hulls each having a longitudinal axis. Each hull having along the longitudinal axis a succession of hollow concrete segments.

A floatable structure in particular a floatable platform including at least two separate hulls each having a longitudinal axis. Each hull having along the longitudinal axis a succession of hollow concrete segments.

A high-performance seafloor flexible oil storage system, solving the existing problems of high storage cost and difficult maintenance of crude oil in offshore oilfields, comprises, sequentially connected, an oil-water separator, a pressure pump, and an input riser extending downward below the sealevel; and a pipeline and multiple flexible oil storage tanks having the same structure with each communicated therewith through a control valve are arranged below the sealevel. One end of the pipeline is communicated with the input riser through a blocking valve and an input valve, and the other end further sequentially connected with an outlet booster pump, an output valve, and an output riser extending upwards above the sealevel and connected to a tanker through a cooler and an output pump. The flexible oil storage tank has a concrete counterweight connected thereunder for fixing it to a seabed. The system has simple structure, convenient maintenance and good practicability.

A high-performance seafloor flexible oil storage system, solving the existing problems of high storage cost and difficult maintenance of crude oil in offshore oilfields, comprises, sequentially connected, an oil-water separator, a pressure pump, and an input riser extending downward below the sealevel; and a pipeline and multiple flexible oil storage tanks having the same structure with each communicated therewith through a control valve are arranged below the sealevel. One end of the pipeline is communicated with the input riser through a blocking valve and an input valve, and the other end further sequentially connected with an outlet booster pump, an output valve, and an output riser extending upwards above the sealevel and connected to a tanker through a cooler and an output pump. The flexible oil storage tank has a concrete counterweight connected thereunder for fixing it to a seabed. The system has simple structure, convenient maintenance and good practicability.

A method for compensating the bathymetric pressure inside a subsea tank containing a liquid working fluid by using a bathymetric compensation fluid is provided. The liquid working fluid and the bathymetric compensation fluid are separated from each other by a separation layer of a separation fluid.