The Offshore Company

Transocean Offshore Inc.

Chevron Research Company

Sonat Offshore Drilling Inc.

Donald R Ray

Robert P Herrmann

Riddle E Steddum

Robert J Scott

Bruce L Crager

Floyd T Pease

Albert M Koehler

Eugene R Facey

Felix S Radovan

A multi-activity driliship, or the like, method and apparatus having a single derrick and multiple tubular activity stations within the derrick wherein primary drilling activity may be conducted from the derrick and simultaneously auxiliary drilling activity may be conducted from the same derrick to reduce the length of the primary drilling activity critical path.

Multi-activity offshore exploration and/or development drill method and

A multi-activity drillship, or the like, method and apparatus having a single derrick and multiple tubular activity stations within the derrick wherein primary drilling activity may be conducted from the derrick and simultaneously auxiliary drilling activity may be conducted from the same derrick to reduce the length of the primary drilling activity critical path.

Multi-activity offshore exploration and/or development drilling method

A variable bearing assembly (40) for a jack-up platform having a hull (12), at least one support leg (14) and jack means (16) to effect relative vertical movement between the hull and support leg wherein the variable bearing assembly (40) includes; a bearing pad or foot (42) surrounding the distal end of the support leg (14) and a lost motion assembly (62, 68) interconnecting the bearing pad and support leg such that the support leg may vertically penetrate the seabed to refusal while the bearing pad is essentially supported on the surface of the seabed.

Jack-up platform variable bearing assembly

A jack-up platform apparatus operable for effecting relative vertical motion between a leg chord of a platform and a deck of the platform. The jack-up apparatus includes at least one generally rectangular reaction member operable to be connected at one end thereof to the platform deck in a posture contiguous to but spaced from a leg chord of the platform. An abutment member is connected to the other end of the reaction member and first and second leg chord engaging members are mounted for selective translation along the reaction member between the abutment member and the platform deck. A jack asembly is mounted between the first and second leg engaging members for translating the members along the reaction member wherein selective actuation of the first and second leg engaging members and the jack assembly will function to effect relative vertical motion between the platform leg chord and the platform deck while the reaction member reacts bending moments across the width thereof.

Jack-up platform apparatus

The invention relates to a method and apparatus for tension mooring an offshore platform having a deck and a plurality of buoyancy columns. An anchor system is initially installed upon the bed of a body of water. Permanent mooring lines are then connected to the anchor system and extend upwardly for support by a buoyancy system located below a lowest portion of the offshore platform and a zone of high oxygen content water adjacent the surface of the body of water. Sacrificial mooring lines are connected to an upper portion of the buoyancy system and extend upwardly through internal conduits with the plurality of bouyancy columns of the floating platform. In the event one of the sacrificial mooring lines becomes damaged the line may be selectively released from the buoyancy system, drawn up through a corresponding interior column and replaced from the deck of the platform.

Method and apparatus for tension mooring a floating platform

A tension mooring system for a floating structure such as a drilling or production platform having a plurality of permanent mooring lines extending upwardly from a plurality of bottom anchors and terminating below the water level and having buoys connected to the upper ends thereof with sufficient buoyancy to maintain the upper end of the mooring lines in a generally vertical posture, replaceable mooring lines connecting from the buoys to the floating structure, the upper position of the permanent mooring lines being preselected to be below a highly corrosive area of the air-sea interface, and a pulling mechanism on the replaceable mooring lines to impart a preselected tension to the mooring lines, the bottom anchors being pre-positioned by drilling and cementing or driving piling through templates. The method of establishing a tension mooring system for a floating structure including the steps of placing a plurality of drilling templates on the bottom at the desired mooring site, drilling and cementing or driving anchor piles through the templates, lowering permanent mooring lines, remotely connecting them to the templates, connecting replaceable mooring lines from the floating structure to the buoys secured to the upper end of the permanent mooring lines, and tensioning the mooring lines to a preselected level.

Method of and apparatus for mooring a floating structure

The invention relates to an offshore, gravity base, jack-up platform comprising a deck, a gravity base and one or more legs interconnecting the deck and base. The gravity base comprises a generally polygonal shaped, monolithic hull structure with reaction members extending downwardly from the hull to penetrate the waterbed and react to vertical and lateral loads imposed upon the platform while maintaining the gravity hull in a posture elevated above the surface of the waterbed. A method aspect of the invention includes the steps of towing a gravity base, jack-up platform, as a unit, to a preselected offshore site floating upon the gravity hull. During the towing operation, the deck is mounted adjacent the gravity base with a leg or legs projecting through the deck. At a preselected offshore station ballast is added to the gravity base and the platform descends slightly to a posture where the platform is buoyantly supported by the deck. The base is then jacked down toward the seabed and the platform is laterally brought onto station. Ballast is then added to the deck and the reaction members are penetrated into the waterbed to operational soil refusal. Ballast is then ejected from the deck and the deck is jacked to an operational elevation above a predetermined statistical wave crest height.

Gravity base, jack-up platform - method and apparatus

A riser for production of oil and gas in a marine location with the riser connected to the casing supported at the mud line of a body of water and extending upward in the water to a tension moored floating structure. The riser includes a flexible joint near its connection to the casing and is supported at its upper end from the floating structure and is also supported from the floating structure at a point between 50 and 175 feet below the water level. A production string extends upwardly from the producing zone through the casing, the flexible joint and the riser to the floating structure and wellhead equipment is supported on such riser. Centralizers are provided for the production string with the centralizer immediately above the flexible joint being between 35 to 65% of the total distance between such centralizer and the centralizer positioned immediately below the flexible joint.

Production riser

A blowout prevention system for an offshore structure positioned on the underwater bottom in a body of water which contains moving ice masses that could force the structure off location wherein a surface blowout preventer stack for conventional well control is connected to the upper end of a riser with the lower end of the riser being disconnectably connected to a subsurface blowout preventer stack which provides the necessary well control should the structure be forced off location. The subsurface stack is positioned on a wellhead located in a chamber in the subsea bottom and is disconnectably connected to the riser so that the riser may be quickly removed from the subsea bottom should the structure be forced off location.

Growing community of inventors

Houston, TX, United States of America

Donald R Ray