Abstract: A system for lifting loads from a mobile offshore platform includes a boom pivotally at one longitudinal end mounted to the platform. A boom extension line is coupled at one end to the boom to cause rotational movement thereof about the pivotally mounted end of the boom. Another end of the boom extension line is either (i) coupled to a movable subplatform on the platform or (ii) supported by a device coupled to the movable subplatform. Movement of the subplatform causes change in effective length of the boom extension line so as to move the boom between an extended position and a retracted position.

Abstract: An apparatus for actuating a ram in a well pressure control apparatus includes an actuator rod coupled to a ram. The actuator rod is movable within a housing to extend the ram into a through bore in the housing. A drive screw is rotationally coupled to the actuator rod. The drive screw is oriented transversely to the actuator rod. At least one motor is rotationally coupled to the drive screw.

Abstract: A power fluid supply system for a well pressure control apparatus includes a control valve manifold in hydraulic communication between a fluid outlet of an hydraulic fluid accumulator and an hydraulic ram in the well pressure control apparatus. A pressurized gas accumulator is in fluid communication with a fluid inlet of the hydraulic fluid accumulator. A pressurized gas supply conduit extends from the pressurized gas accumulator to a source of pressurized gas.

Abstract: A method for assembling a riser from a platform on the surface of a body of water includes assembling segments of riser end to end through a drill floor using a main drilling unit on the platform. At least one auxiliary line is assembled from segments connected end to end through an auxiliary hoisting unit on the platform. The auxiliary hoisting unit is displaced laterally from the main drilling unit. The assembled riser is connected to a wellhead proximate the bottom of the body of water.

Abstract: A method for excavating a well cellar includes lowering an excavating apparatus having a cellar liner therein to a bottom of a body of water. The well cellar is excavated while contemporaneously lowering the cellar liner into the well cellar until a top of the cellar liner is substantially level with the bottom of the body of water. A pilot well is excavated below a bottom of the cellar. A well head support pipe is inserted into the pilot well. The bottom of the well cellar and a top of the cellar liner are covered.

Abstract: A method for abandonment of a production platform includes moving a mobile offshore service platform (MOSP) to a position proximate the production platform. A hull of the MOSP is raised to a selected elevation above a top of the production platform. A cantilever structure having thereon a drilling unit and a crane is extended from a retracted position over the hull until the drilling unit is positioned over at least one well on the production platform. The well is plugged. The cantilever structure is then moved so that the crane is positioned to lift components from the production platform during disassembly of the production platform.

Abstract: A fluid containment system for a riser slip joint includes a fluid container sealingly engaged to a fixed part of the slip joint. A movable part of the slip joint is axially movably engaged with the fixed part. An annular seal is disposed between the fixed part and the movable part. A body of fluid disposed in the fluid container has a level selected to submerge the annular seal and at least a portion of the movable part. The system includes means for maintaining a level of the body of fluid substantially constant.

Abstract: An apparatus for actuating a ram in a well pressure control apparatus includes an actuator rod coupled to a ram. The actuator rod is movable within a housing to extend the ram into a through bore in the housing. A drive screw is rotationally coupled to the actuator rod. The drive screw is oriented transversely to the actuator rod. At least one motor is rotationally coupled to the drive screw.

Abstract: A method for excavating a well cellar includes lowering an excavating apparatus having a cellar liner therein to a bottom of a body of water. The well cellar is excavated while contemporaneously lowering the cellar liner into the well cellar until a top of the cellar liner is substantially level with the bottom of the body of water. A pilot well is excavated below a bottom of the cellar. A well head support pipe is inserted into the pilot well. The bottom of the well cellar and a top of the cellar liner are covered.

Abstract: A fluid containment system for a riser slip joint includes a fluid container sealingly engaged to a fixed part of the slip joint. A movable part of the slip joint is axially movably engaged with the fixed part. An annular seal is disposed between the fixed part and the movable part. A body of fluid disposed in the fluid container has a level selected to submerge the annular seal and at least a portion of the movable part. The system includes means for maintaining a level of the body of fluid substantially constant.

Abstract: A jackup mobile offshore drilling unit includes a hull and a plurality of jacking legs movable longitudinally with respect to the hull and having features thereon to support the hull above a body of water. A storage tank is disposed inside at least one of the plurality of jacking legs. The unit comprises means for moving the storage tank longitudinally inside the at least one of the plurality of jacking legs.

Abstract: A tender barge for a drill ship includes a hull internally segmented into compartments. The compartments are for storing wellbore drilling consumables and wellbore drilling waste. The hull has an opening therein for positioning under a moon pool of a drill ship. The barge hull further includes a support structure for contacting a bottom of a hull of a drill ship when the drill ship is positioned over the barge hull. The barge has a mooring system having capacity to either hold the barge in position or hold both the barge and the drill ship when the drill ship is fully supported by the barge out of the water over a wellbore location.

Abstract: A method for preparing to move a floating structure away from a wellbore drilled below the bottom of a body of water includes filling a riser extending from the bottom of the body of water to the floating structure with water. The water in the riser is displaced to a selected first depth below the water surface. The riser is sealed at a second selected depth shallower than the first selected depth. The portion of the riser above the second selected depth is withdrawn onto the floating structure.