Abstract: A rugged screw-threaded pipe connector for handling corrosive or contaminating fluids under high pressure in a pipeline or pipe riser surrounded by a body of water and subject to high static or dynamic stresses and bending forces. The connector is provided with coarse threads having stabbing flanks and with load flanks adapted to support high loads. The connector is provided with multiple sealing means arranged within the body of the connector that isolate the threads from fluids outside the connector or within the bore of the connector.

Abstract: 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.

Abstract: 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.

Abstract: A method of providing a cathodic protection to an installed pile is disclosed in which a plurality of anodes are provided on a tendon foundation guide assembly which is attached to a lowering unit and lowered to the pile. The tendon foundation guide assembly is attached to the installed pile and at least one of the anodes is electrically connected to the pile. The tendon foundation guide assembly is then separated from the lowering unit. In another aspect of the invention, a tendon foundation guide assembly is disclosed for deployment upon the top of an installed pile for cathodically protecting the pile and a tendon receptacle inside the pile.

Abstract: 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.

Abstract: An improved pipe section is disclosed for installation into a subsea pipeline. A pipe section in accordance with the present invention provides a length of pipe having a pipe wall and at least a first bearing shoulder projecting circumferentially outward from the pipe wall whereby the pipe section may be handled by supporting the pipe section from the first bearing shoulder during installation. The first bearing shoulder also prevents propagation of buckling failure in the subsea pipeline constructed from such pipe sections and the first bearing shoulder remains available for pipeline retrieval operations in the event of localized failure in the subsea pipeline.

Abstract: An offshore pipeline system is provided, comprising a pipe section which is curved so as to bend upon a variation of the distance between the ends thereof. The pipe section is provided with a pair of first connectors extending in downward direction, each first connector being located at one of said ends of the pipe section. The system further comprises a pair of second connectors extending in upward direction and located at a distance relative to each other so as to allow connection of each first connector to one of said second connectors, means for lowering the pipe section through the water towards the second connectors and guide means for guiding each first connector towards one of said second connectors when the pipe section is lowered through the water so as to connect the first connectors to the second connectors.

Abstract: An offshore platform structure is disclosed for facilitating use of a jack-up rig for well operations in deepwater applications while reducing the jacket size and increasing the flexibility of field development. The structure has a bottom founded jacket base and a surface tower supported by the jacket base and extending above the ocean surface. A platform deck is supported by the surface tower and a subsea rig support interface is presented at the top of the jacket base which is adapted to receive the jack-up rig for well operations. Another aspect of the present invention is an offshore platform system which includes a jack-up rig having a plurality of legs extending from a combination hull/deck structure and engaging the rig support interface. Well operations equipment provided by the jack-up rig which includes a cantilever deck extending from the combination hull and deck structure to present a derrick in substantial vertical alignment with the surface tower.

Abstract: An improved support system is disclosed for providing flexibility to a restrained termination of a highly pressurized, highly tensioned tubular element which extends from a subsea facility to a compliant structure. The tubular element is provided with an intermediate tension relief connection which separates a running span from a backspan and operably connects the tubular element to a support structure, transfering thereto a significant portion of the tension carried by the tubular element. This connection passes angular rotation of the tubular element but resists lateral motion, in effect forming a node in the deflection of the tubular element. A backspan is thus created in the tubular element having a tension load which is reduced from that in the running span, thereby increasing the flexibility apparent at the end of the running span, while maintaining a relatively restrained termination of the tubular element at the distal end of the backspan.

Abstract: The present invention is a reusable jacket base for an offshore platform having a plurality of jacket legs with an interconnecting framework. Pile sleeves are connected to the jacket legs which have a vertically extended, open-ended cylindrical member having a second stage sleeve which is connected to the jacket leg and a first stage sleeve projecting coaxially from the second stage sleeve. First and second stage locking profiles are presented inside the first and second stage sleeves, respectively. The first stage sleeve is thus accessible for cutting operations, severing both the first stage sleeve with the first pile-to-pile sleeve connection inside and the connected pile section within. This allows retrieval of the platform jacket, but preserves a second stage pile sleeve for re-deployment. Another aspect of the present invention is an improved pile sleeve adapted to facilitate reuse.

Abstract: 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.

Abstract: 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.

Abstract: An improved method for conducting offshore well operations is disclosed in which a compliant platform is installed adjacent a selected well site and an auxiliary vessel is temporarily docked to the compliant platform to provide for support for the well operations which will be produced through the compliant platform. In the practice of the improved method, the compliant platform is isolated from vertical loads upon the auxiliary vessel docked thereto during the performance of well operations conducted for the compliant platform by the offshore auxiliary vessel. Another aspect of the present invention is an improved system for restraining an offshore drilling vessel temporarily to a compliant platform which uses a slide-connection for isolating the compliant platform from vertical loads upon the offshore drilling vessel during the well operations.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method 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.

Abstract: A heave compensating support system is disclosed for positioning a subsea work package. The present invention provides a subsurface buoy with a lift line connected to the subsea work package and a compensating lift line having a catenary loop below its connection to the subsurface buoy on one end and connected to a surface vessel on the other end, whereby the heave compensating support system elements cooperate to establish a natural frequency for the suspended subsea work package which materially differs from the average wave frequency acting upon the surface vessel.

Abstract: A tension leg well jacket ("TLWJ") is disclosed which is configured to receive well operations support from an offshore drilling vessel docked thereto and to receive the production riser in transfer operations from the vessel to the TLWJ. This permits a minimal platform suitable for supporting production risers which is particularly useful in deep water applications.