Abstract: Systems, apparatuses, and methods for removing fixed offshore platforms using a semi-submersible marine vessel are described. The semi-submersible marine vessel may comprise a main body, a mooring system, a lifting system, and a gate disposed at the second end. The main body may have an extended shape sized to house a fixed offshore platform oriented in a prone position. The main body may have a first end opposing a second end and a first side opposing a second side, the first end and the second end having dimensions that exceed dimensions of a footprint of the fixed offshore platform, the first side and the second side having dimensions that exceed dimensions of the fixed offshore platform oriented in a prone position. The lifting system may have a plurality of strand jacks and plurality of strand jack cables.

Abstract: A floating production system, comprising a superstructure configured to float on the sea, such that portions of the superstructure are configured to rest above and below the surface of the sea. A mooring system is configured to moor the superstructure to the seabed using neutrally buoyant mooring lines of steel pipes. The mooring system may be arranged in catenary. One or more risers disposed between the seabed and a semi-submersible platform, arranged in a curtain, are configured to facilitate the transport of liquid material from the seabed toward the surface of the sea. Liquid material may be stored in storage tanks disposed in vertically-disposed legs extending downward from the upper portion of the superstructure and/or in horizontally-disposed pontoons extending between at least two of the legs. The horizontally-disposed pontoons may form a square ring providing tanks for oil over water storage and/or dry storage.

Abstract: This invention relates to a method and to an apparatus for use in laying a submarine pipeline from a pipe-laying vessel. According to one aspect of the present invention, there is provided a reel pipe-laying method for continuously laying a pipeline of up to 24-inch diameter without a stinger by (1) aligning a pipe portion as it is being paid out from the reel, (2) straightening the aligned pipe portion, (3) tensioning the pipe, (4) discharging the straightened pipe under tension into the body of water, and (5) changing for different water depths and pipe conditions the lift off angle of the pipe relative to the horizontal by pivoting a diverter about a horizontal pivot, the diverter supporting at least the straightener and the tensioner and extending from the horizontal pivot mounted near the aft end of the vessel, upwardly toward the reel.