Multi-cellular floating platform with central riser buoy

摘要

A semi-submersible floating platform for offshore drilling and/or production of petroleum product from the seabed includes a base having a first moon pool; a plurality of vertical outer buoyancy columns extending upwardly from the base; a deck structure supported by the buoyancy columns and having a second moon pool; a central columnar buoyancy apparatus having a lower portion guided within the first moon pool and an upper portion guided within the second moon pool; and at least one vertical riser passing through the buoyancy apparatus. Each riser has a lower portion that is horizontally restrained within the buoyancy apparatus below the center of gravity thereof. In a preferred embodiment, the platform includes at least two vertical risers attached to a single buoyancy apparatus.