Shell Oil Comapny

Shell Offshore Inc.

David A Huete

Lee K Brasted

Denby Grey Morrison

Peter W Marshall

Susan L Smolinski

George Rodenbusch

George Rodenbush

Romulo Gonzalez

Anders G Ekvall

Paul R Johnson

Dale Richard Snyder

Earl Howard Doyle, Jr

Richard Garside

Curtis J Lohr

A method of installing a foundation system for securing the tendons of a TLP to the ocean floor. The foundation system is installed in templateless operations in which a pile is secured to the ocean floor and a tendon receptacle is secured to the pile such that the load from a tendon secured therein is transferred to the ocean floor through coaxially aligned load paths of tendon-to-tendon receptacle-to-pile-to-ocean floor.

Method for templateless foundation installation

A parasite mooring system is disclosed for restraining a compliant platform with respect to an auxiliary vessel. The parasite mooring system includes a parasite mooring line, a platform termination securing the parasite mooring line to the compliant platform; and a grip securing the parasite mooring line to a mooring line of the auxiliary vessel passing beyond the compliant platform. Another aspect of the present invention is a method for conducting offshore well operations in which a semisubmersible vessel is brought adjacent a compliant platform such that at least one mooring line of the semisubmersible vessel extends past the compliant platform and a parasite mooring line from the compliant platform is connected to the mooring line of the semisubmersible vessel. The parasite mooring line can then be tensioned to displace and restrain the compliant platform out of its normal position substantially over a well pattern and position the semisubmersible vessel over a selected well site within the well pattern at a location at the surface of the water which is not accessible to the semisubmersible vessel with the compliant platform in its normal position.

Complaint platform with parasite mooring through auxiliary vessel

A compliant tower is disclosed having a foundation connected to a wide-bodied compliant framework with a plurality of vertically extending legs a minimum of horizontal bracing. The compliant framework is configured to maintain a substantially wide, open riser suspension corridor. A topside facility is supported by the compliant framework and a plurality of freely suspended production risers extend through the riser suspension corridor from the vicinity of the topside facility to communicate with the reservoir. These production risers are spaced to provide clearance to prevent riser interference in response to normal flexure of the compliant tower and normal environmental loads on the risers. A riser support assembly is configured to accomodate relative motion between the risers and the topside facility, supporting the production risers in tension near their upper ends to provide the principal load transfer between the riser and the compliant framework.

Compliant tower

A tendon cluster array is disclosed for tethering a superstructure of a tension leg platform to an ocean floor in which a plurality of tendons are anchored to the ocean floor at their lower ends with a substantially planar, horizontally disposed tendon bracket receiving the upper ends. A tendon bracket connection pivotally secures the tendon bracket to a downwardly disposed surface of the superstructure.

Tendon cluster array

The present invention is a deepwater compliant platform that has enhanced dynamic characteristics by virtue of its wide stance, eliminates conventional conductor drivepipe guides and supporting framework, and reduces the net material requirements with a substantially open interior permitted in the absence of the conductor guides. This utilizes the wide body stance to accommodate a wide riser suspension corridor through the open interior thereby allowing suspended risers to be spaced apart sufficiently to avoid interference in response to normal tower motions.

Lightweight, wide-bodied compliant tower

A tension leg caisson is disclosed for supporting surface facilities on a deck for conducting hydrocarbon recovery operations in deepwater location applications. The tension leg caisson has an elongated, buoyant central vertical column or caisson with a plurality of outrigger pontoons. A plurality of tendons are connected on one end to the outrigger pontoons at a location which is spaced apart from the vertical. The other end is anchored to the ocean floor. Another aspect of the invention is a method of improving the dynamic response of a buoyant central caisson type platform.

Tension leg caisson and method of erecting the same

A tension leg tripod is disclosed for supporting surface facilities on a deck for conducting hydrocarbon recovery operations in deepwater location applications. The tension leg tripod has an elongated, buoyant central vertical column or caisson with three outrigger pontoons. Three tendons are grouped in tendon cluster arrays, each being connected on one end to the outrigger pontoons at a location which is spaced apart from the vertical. The other end of the tendons are anchored to the ocean floor.

Minimal tension leg tripod

A method for conducting offshore well operations is disclosed in which a compliant platform is restrained out of its normal position substantially over a well pattern by adjusting a first lateral mooring system connecting the compliant platform to a first array of anchors secured to an ocean floor. An offshore drilling vessel is then positioned over a selected well site of the well pattern at a location at the surface of the water not accessible to the offshore drilling vessel with the compliant platform in its normal position by adjusting a second lateral mooring system connecting the compliant platform to a second array of anchors on the ocean floor. Well operations are then conducted through a substantially vertical riser while maintaining a clearance to prevent direct contact between the compliant platform and the offshore drilling vessel.

Method for conducting offshore well operations

The present invention is a method for reducing the natural period of the second harmonic response in a deepwater compliant tower by decoupling the mass of the production risers from the vertically extending compliant framework.

Method for improving the harmonic response of a compliant tower

A tensioned riser deepwater platform suitable for offshore oil and gas applications is disclosed having a foundation secured to the ocean floor, a topside facility above the ocean surface, and a vertically extending tower jacket secured to the foundation and supporting the topside facility. A plurality of substantially vertically extending risers provide fluid communication between the wells and the topside facility. These risers are connected to riser supports near their upper ends and the riser supports provide the principal load transfer between the risers and the tower jacket. Thus, the conductor guides and attendant horizontal bracing of conventional deepwater design can be substantially eliminated.

Tensioned riser compliant tower

A bumper system is disclosed for docking an auxiliary drilling vessel to a compliant platform through first and second pads having vertically extending, complementary outboard faces presented from the respective structures in vertically slidable abutment. A biasing system pushes the vessel and platform into abutment across the first and second pads and the system allows the vessel to dock to the structure in a manner such that vertical loading is not substantially transmitted between the vessel and the structure across the sliding engagement.

Bumper docking between offshore drilling vessels and compliant platforms

A tensioned riser deepwater platform suitable for offshore oil and gas applications is disclosed having a foundation secured to the ocean floor, a topside facility above the ocean surface, and a vertically extending tower jacket secured to the foundation and supporting the topside facility. A plurality of vertically extending risers provide fluid communication between the wells and the topside facility. These risers are connected to riser supports near their upper ends. The riser supports provide the principal load transfer between the risers and the tower jacket and the conductor guides and attendant horizontal bracing are substantially eliminated from the design.

Tensioned riser deepwater tower

A method and system are disclosed for establishing hydrocarbon production for offshore reservoirs in which a compliant platform is installed at a selected site, an offshore drilling vessel is docked to the compliant platform and the vessel is positioned over a selected well site for conducting drilling operations, and the production riser is transferred from the vessel to the compliant platform and secured there. Communication between a surface tree installed on the production riser and facilities supported by the compliant platform is established and these steps are repeated for each selected well site served by the compliant platform.

Method and system for developing offshore hydrocarbon reserves

A method is disclosed for conducting offshore well operations from an auxiliary vessel in support of a compliant platform. The auxiliary offshore drilling vessel is restrained with respect to the compliant platform in position adjacent the well bay of the compliant platform and vertically aligned with a selected well site for conducting well operations.

A method is disclosed for conducting offshore well operations from an auxiliary vessel in support of a compliant platform. The auxiliary offshore drilling vessel is docked to the compliant platform and is positioned over a selected well site for conducting drilling operations by driving the compliant platform out of alignment as necessary to bring the well operations facilities of the auxiliary vessel docked thereto into substantially vertical alignment. The production riser is transferred from the auxiliary vessel to the compliant platform after well operations are complete.

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Spring, TX, United States of America

David A Huete