Abstract: Method and apparatus to stabilize a columnar platform for deepwater offshore applications. An added mass stabilizer system is utilized to control first order heave, pitch, roll, surge and sway motions of the floating platform. The stabilizer is suspended beneath the platform by a set of tendons a sufficient distance to (1) enter a quiescent zone beneath the action of waves and currents, (2) provide a sufficiently long movement arm to resist pitch and roll torquing, and (3) incorporate sufficient flexibility into the suspension system to avoid shock loads. The stabilizer is sized to (a) provide sufficient submerged weight to maintain the tendons in constant tension and, (b) create adequate added mass (actual stabilizer weight plus mass of water moved by the stabilizer) to provide the desired control of first order motions. A secondary mooring system such as a spring-buoy mooring or dynamic positioning system can be provided to control drift produced by higher order motions and first order yaw.

Abstract: A tension-restricted articulated platform tower for offshore oil and gas production. Two or more tower segments of increasing lateral dimension (proceeding toward the ocean floor) are stacked and articulated by means of a resilient joint. The platform tower behaves as a fixed tower under normal quiescent conditions with each of the segments above the base segment sitting thereabove in an at rest position. When forces sufficient to unseat the compressed resilient joint element are directed against the platform tower (e.g., from wind, waves, or water current), the tower behaves complaintly with tension elements secured to each corner post providing a restorative force proportional to the amount of tower movement.

Abstract: A method and apparatus for supporting a deep water guyed marine structure has a foundation which uses a system of piles connected to the marine structure only at a top portion thereof. The marine structure further has a mooring system which employs pairs of transversely, closely spaced guy lines connected to clump weights and further pairs of transversely, closely spaced guy lines connected from the clump weights to an anchor system. The marine structure mooring system can further provide a vessel mooring system in order to provide adequate control of the vessels during on and off loading of the marine structure and further to prevent fouling of the marine structure mooring system.

Abstract: Methods and apparatus for offshore operations including individually significant aspects comprising:1. Methods and apparatus for providing lateral force transmitting arch means extending across a vessel passageway which is laterally bounded by upwardly projecting portions of a substructure and bounded on the top by an integrated deck:2. Methods and apparatus for assemblying an integrated deck with a substructure wherein there are effected horizontal and vertical shock absorbing action, motion dampening, and desired alignment; and3. Methods and apparatus for assemblying an integrated deck with a substructure wherein, at a relatively slower rate, an integrated deck is lowered into engagement with a substructure and, at a subsequent more rapid rate, a vessel initially supporting the integrated deck is vertically separated therefrom.

Abstract: To connect two submerged conduits (e.g., a pipeline and a riser), a buffer unit is placed intermediate the two conduits. the buffer unit comprises an enclosure having a projecting conduit segment for attachment to each ofthe submerged conduits. An expansion mechanism is supported in the enclosure and interconnects the projecting conduit portions. The internal structure of the enclosure is such as to accommodate movement of the expansion mechanism (to accommodate, for example, thermal expansion or contraction of one of the submerged conduits), thereby isolating each of the submerged conduits from forces experienced by the other. Also disclosed are the use of positioning mechanisms to change the orientation of the expansion mechanism within the enclosure in order to change the position and/or orientation of the projecting conduit portions to facilitate coupling to the submerged conduits.

Abstract: A method and apparatus for supporting a deep water guyed marine structure has a foundation which uses a system of piles connected to the marine structure only at a top portion thereof. The marine structure further has a mooring system which employs pairs of transversely, closely spaced guy lines connected to clump weights and further pairs of transversely, closely spaced guy lines connected from the clump weights to an anchor system. The marine structure mooring system can further provide a vessel mooring system in order to provide adequate control of the vessels during on and off loading of the marine structure and further to prevent fouling of the marine structure mooring system.