Abstract: A vessel with drilling and workover capability is constructed rapidly in a shipyard or dry dock by using an existing vessel that has most of the required hull. Bow and stern sections of the existing vessel are separated to leave them at opposite ends of a shipyard space, and a mid hull section is built in that shipyard space in the usual manner by welding together steel plates. The bow and stern sections are moved against opposite ends of the mid hull section and welded to it. Topside equipment is already on the bow and stern sections, and is added to the new mid hull section.

Abstract: A vessel with drilling and workover capability is constructed rapidly in a shipyard or dry dock by using an existing vessel that has most of the required hull. Bow and stern sections of the existing vessel are separated to leave them at opposite ends of a shipyard space, and a mid hull section is built in that shipyard space in the usual manner by welding together steel plates. The bow and stern sections are moved against opposite ends of the mid hull section and welded to it. Topside equipment is already on the bow and stern sections, and is added to the new mid hull section.

Abstract: An offshore hydrocarbon production system includes a vessel (12) with a turret (16), and a fluid swivel (50) on the turret that is connected to risers (41–43) that extend to the sea floor (26), wherein a drilling/workover rig (60) on the vessel can lower tubing (65) toward the sea floor without danger that the tubing will wrap about the risers when the hull weathervanes. The rig is mounted on the turret. Pipes (54) that extend from the rotatable part of the fluid swivel to fittings (55) on the hull (14), are supported on a gantry (80) that is fixed to the hull and having a gantry middle portion (106) that extends over the turret. The gantry middle portion extends higher than the top (88) of the rig.

Abstract: A system is provided for more efficiently using offshore produced hydrocarbons, where the produced hydrocarbons contain considerable amounts of liquid hydrocarbons and both heavy gaseous hydrocarbons (at least two carbon atoms per molecule) and light hydrocarbons (with two or less carbon atoms per molecule). The produced hydrocarbons are separated into liquid hydrocarbons which are stored in a tank structure (183) for later offloading to a tanker (56), and into heavy gaseous hydrocarbons and light hydrocarbons. The heavy gaseous hydrocarbons are liquefied and stored in a tank (212) for fueling an electricity generator unit (192) when needed, and the light hydrocarbons are immediately used to fuel the electricity generator unit (192).

Abstract: A system for using natural gas to safely provide large amounts (at least 30 megawatts) of electricity to consumers. The system includes a floating generating vessel (110) that lies offshore and carries one or more turbine-generator sets (114, 116) that use natural gas as fuel and whose electricity output is delivered though a power line (138) that extends at least partially in the sea to a consumer. One consumer is a process vessel (112) that processes natural gas and that has transfer facilities (68) that transfer liquified gas to or from a tanker (106) that holds over 10,000 tons of liquified gas. Some of the gas is transferred from the process vessel through a conduit (136) in the sea to the generating vessel (110) to provide fuel. Another consumer is an onshore facility (52). The generating and process vessels (110, 112) are widely separated (e.g. at least 0.2 kilometer) to protect personnel in the event of a gas explosion or fire.

Abstract: A very large hydrocarbon production vessel (10) of at least 40,000 tons steel weight, is constructed without requiring a very long reserve time period in a very large dry dock. The hull of the vessel is constructed in at least three different hull sections, including a midship hull section (24) and bow and stern hull sections (20, 22), with each preferably constructed at a different construction site. The hull sections are then brought together in a very large dry dock and welded together, so a minimum amount of time must be reserved in the very large dry dock. The midship hull section is preferably constructed in a specialized shipyard, and the same shipyard installs drilling equipment (50) and equipment that connects to risers that bring up hydrocarbons, so the expertise of the shipyard is used for both the midsection hull construction and specialized drilling and riser handling equipment.

Abstract: An offshore hydrocarbon production system includes a vessel (12) with a turret (16), and a fluid swivel (50) on the turret that is connected to risers (41-43) that extend to the sea floor (26), wherein a drilling/workover rig (60) on the vessel can lower tubing (65) toward the sea floor without danger that the tubing will wrap about the risers when the hull weathervanes. The rig is mounted on the turret. Pipes (54) that extend from the rotatable part of the fluid swivel to fittings (55) on the hull (14), are supported on a gantry (80) that is fixed to the hull and having a gantry middle portion (106) that extends over the turret. The gantry middle portion extends higher than the top (88) of the rig.

Abstract: A very large hydrocarbon production vessel (10) of at least 40,000 tons steel weight, is constructed without requiring a very long reserve time period in a very large dry dock. The hull of the vessel is constructed in at least three different hull sections, including a midship hull section (24) and bow and stern hull sections (20, 22), with each preferably constructed at a different construction site. The hull sections are then brought together in a very large dry dock and welded together, so a minimum amount of time must be reserved in the very large dry dock. The midship hull section is preferably constructed in a specialized shipyard, and the same shipyard installs drilling equipment (50) and equipment that connects to risers that bring up hydrocarbons, so the expertise of the shipyard is used for both the midsection hull construction and specialized drilling and riser handling equipment.