Offshore column tension leg platform

Abstract

An apparatus and methods for installation of an offshore platform for supporting equipment installations is provided. The apparatus includes a vertical compression assembly and a counteracting tensioning tendon system. The vertical compression assembly may comprise multiple compression members, a column truss, or other configurations. The methods of fabrication, load out, and installation provide for cost-effective port and installation vessel requirements.

1 . An offshore installation comprising:
 a top platform;   a foundation configured to be disposed on a seafloor;   a vertical compression assembly comprising:
 a first end connected to the top platform; 
 a second end connected to the foundation; 
 at least one compression member extending from the first end to the second end; 
   a plurality of tendons configured to extend from the top platform to the foundation; and   a plurality of mooring cables configured to extend from the top platform to the seafloor.   
     
     
         2 . The offshore installation of  claim 1 , wherein the vertical compression assembly further comprises a plurality of compression members extending from the first end of the vertical compression assembly to the second end of the vertical compression assembly. 
     
     
         3 . The offshore installation of  claim 1 , wherein the top platform further comprises:
 a center point;   a first leg extending outward from the center;   a second leg extending outward from the center;   a third leg extending outward from the center; and   wherein the first leg, second leg, and third leg are all on the same plane.   
     
     
         4 . The offshore installation of  claim 3 , wherein the foundation further comprises:
 a center point;   a first leg extending from the center point to an outward end;   a second leg extending from the center point to an outward end;   a third leg extending from the center point to an outward end; and   wherein the first leg, second leg, and third leg are all on the same plane.   
     
     
         5 . The offshore installation of  claim 4 , further comprising at least three tendons, wherein, a first tendon extends from the outward end of the first leg of the top platform to the outward end of the first leg of the foundation;
 a second tendon extends from the outward end of the second leg of the top platform to the outward end of the second leg of the foundation; and   a third tendon extends from the outward end of the third leg of the top platform to the outward end of the third leg of the foundation.   
     
     
         6 . The offshore installation of  claim 4 , wherein the foundation further comprises a weighted basket configured to maintain a position of the foundation on the seafloor. 
     
     
         7 . The offshore installation of  claim 1 , wherein the vertical compression assembly further comprises a plurality of compression members spaced equidistant from each other. 
     
     
         8 . The offshore installation of  claim 1 , further comprising a compression member guide comprising a slot configured to accommodate a lateral displacement of a compression member. 
     
     
         9 . The offshore installation of  claim 8 , wherein the compression member guide comprises a plurality of slots equal to a number of compression members. 
     
     
         10 . The offshore installation of  claim 1 , wherein the compression member comprises a column truss. 
     
     
         11 . The offshore installation of  claim 1 , further comprising a wind turbine configured to be mounted on the top platform. 
     
     
         12 .- 21 . (canceled)