Abstract: A semi-submersible structure with buoyant vertical columns and a buoyant pontoon. Unlike the typical semi-submersible where the pontoons are attached directly between the columns, the pontoon of the invention encircles the columns and is arranged outside of the columns. The pontoon encircling the columns simplifies construction and attachment of the pontoon and columns and improves the heave characteristics of the structure.

Abstract: A semi-submersible structure with buoyant vertical columns and a buoyant pontoon. Unlike the typical semi-submersible where the pontoons are attached directly between the columns, the pontoon of the invention encircles the columns and is arranged outside of the columns. The pontoon encircling the columns simplifies construction and attachment of the pontoon and columns and improves the heave characteristics of the structure.

Abstract: A semi-submersible structure with buoyant vertical columns and a buoyant pontoon. Unlike the typical semi-submersible where the pontoons are attached directly between the columns, the pontoon of the invention encircles the columns and is arranged outside of the columns. The pontoon encircling the columns simplifies construction and attachment of the pontoon and columns and improves the heave characteristics of the structure.

Abstract: A TLP design with improved motion characteristics and that is drawn to a means of reducing the required tendon stiffness and thereby reducing the overall cost of deepwater TLPs. The invention reduces the hydrodynamic added mass of the TLP hull. The horizontal pontoons that connect the vertical columns of the TLP are shaped to reduce the hydrodynamic added mass of the structure in the vertical direction.

Abstract: A floating spar hull for offshore oil and natural gas exploration and production having a centerwell arrangement wherein a supporting wellbay deck is positioned in the centerwell at a level below the uppermost portion of the spar hull in the centerwell. The wellbay deck is attached to the spar hull by any suitable means such as shear plates such that a space remains between the deck and the spar hull for risers. This allows equipment to be placed below the uppermost deck of the topsides and eliminates or minimizes wind loads on the equipment.

Abstract: A mooring disconnect arrangement for a floating offshore structure and a mooring buoy. At least one high pressure water jet is positioned to direct water between the floating offshore structure and the mooring buoy. The floating offshore structure and mooring buoy are also provided with specially shaped complementary surfaces to assist in disconnection and separation. One or more mechanical restraining devices may be used to retain the floating offshore structure and mooring buoy connected together during normal drilling or production operations.

Abstract: A floating spar hull for offshore oil and natural gas exploration and production having a centerwell arrangement wherein a supporting wellbay deck is positioned in the centerwell at a level below the uppermost portion of the spar hull in the centerwell. The wellbay deck is attached to the spar hull by any suitable means such as shear plates such that a space remains between the deck and the spar hull for risers. This allows equipment to be placed below the uppermost deck of the topsides and eliminates or minimizes wind loads on the equipment.