Cellular SPAR apparatus and method

Abstract

According to various aspects of the invention, a buoyancy apparatus, a buoyancy system and a buoyancy method are provided. In one example embodiment of the present invention, a buoyancy apparatus for drilling and production caisson is provided for use in deep water offshore well operations. The buoyancy apparatus comprises a central cell, and a plurality of secondary cells essentially surrounding the central cell and secured to the central cell; wherein the perimeter surface of the buoyancy apparatus is essentially continuous along the length of at least the secondary cells. In one example embodiment, rigidly connecting the central cell and the secondary cells creates void chambers. The tops, bottoms, and sides, of the void chambers are sealed for buoyancy or production fluid storage. In another example embodiment, the void chambers have open bottoms. Another example embodiment comprises a mixture of sealed and open bottomed void chambers. In yet another example embodiment of the buoyancy apparatus comprises non-traditional curved shapes, rigidly connected. In alternate embodiments, any combination of the central cell, secondary cell, and the void chambers provide fixed ballast, variable ballast, buoyancy, or production storage as will occur to those of ordinary skill in the art.

I claim:  
     
         1 . A buoyancy apparatus for a drilling and production caisson for use in deep water offshore well operations, comprising: 
 a) a central elongated cell defining a center well;    b) an elongated member connected to the central cell on one end and connected at the other end on a secondary cell or on a secondary elongated member;    c) said secondary cell or secondary elongated member being directly connected to the central cell or being connected to the central cell through a succession of complimentary elongated members and/or complimentary cells, wherein said cells and/or elongated members unaccompanied or in combination with each other define an elongated chamber;    d) wherein said cells and/or elongated chambers are used for buoyancy or variable ballast, or a combination of thereof.    
     
     
         2 . The buoyancy apparatus of  claim 1 , wherein a perimeter surface of the buoyancy apparatus is essentially continuous along the length of at least one elongated chamber.  
     
     
         3 . The buoyancy apparatus of  claim 1 , wherein the perimeter comprises openings for water flow.  
     
     
         4 . The buoyancy apparatus of  claim 1 , wherein said elongated chambers further comprise void chambers.  
     
     
         5 . The buoyancy apparatus of  claim 1 , wherein said secondary cell further comprises a circular cross-section.  
     
     
         6 . The buoyancy apparatus of  claim 1 , wherein said secondary cell further comprises a non-circular cross-section.  
     
     
         7 . The buoyancy apparatus of  claim 6 ,wherein said secondary cell further comprises an egg-shaped cross-section.  
     
     
         8 . The buoyancy apparatus of  claim 1 , wherein the elongated members comprise metal surfaces.  
     
     
         9 . The buoyancy apparatus of  claim 1 , further comprising a plurality of elongated members comprising curved shapes essentially surrounding the central cell; 
 wherein one end of each elongated member is secured to the central cell and the other end of each elongated member is secured to a secondary elongated member.    
     
     
         10 . The buoyancy apparatus of  claim 1 , wherein the elongated member further comprises a radial elongated member and the secondary elongated member further comprises a longitudinal elongated member; wherein said radial elongated member is essentially perpendicular to said longitudinal elongated member.  
     
     
         11 . The buoyancy apparatus of  claim 10 , further comprising π-shaped cells essentially surrounding the central cell.  
     
     
         12 . The buoyancy apparatus of  claim 1 , further comprising an interstitial chamber.  
     
     
         13 . The buoyancy apparatus of  claim 12 , further comprising a bulkhead within said interstitial cell.  
     
     
         14 . The buoyancy apparatus of  claim 12 , further comprising a water opening in the interstitial chamber.  
     
     
         15 . The buoyancy apparatus of  claim 14 , further comprising an air pump.  
     
     
         16 . The buoyancy apparatus of  claim 1 , further comprising a bulkhead within said secondary cell.  
     
     
         17 . The buoyancy apparatus of  claim 1 , further comprising a water opening at essentially the bottom of the secondary cell.  
     
     
         18 . The buoyancy apparatus of  claim 1 , further comprising a bulkhead within said elongated chamber.  
     
     
         19 . The buoyancy apparatus of  claim 1 , further comprising a water opening at essentially the bottom of the elongated chamber.  
     
     
         20 . A method of constructing a buoyancy apparatus, the method comprising: 
 attaching a central cell to a first secondary cell with a first elongated member,    attaching a second secondary cell to the first secondary cell and the central cell with a second elongated member and a third elongated member, thereby creating a void chamber between the central cell, the first secondary cell, and the second secondary cell, and    continuing to attach a plurality of secondary cells to the central cell with a plurality of elongated members, until a loop of secondary cells and a plurality of void chambers are formed.    
     
     
         21 . The method of  claim 20  wherein: 
 the central cell and the secondary cells comprise substantially elongated cells,  
 the central cell is supported lengthwise in water, and  
 the central cell is rotated between the attaching the central cell to the first secondary cell and the attaching the second secondary cell to the first secondary cell.  
 
     
     
         22 . The method of  claim 21 , wherein the secondary cell buoyancy cells comprise metal.  
     
     
         23 . The method of  claim 21 , wherein the attaching comprises welding.  
     
     
         24 . The method of  claim 21 , wherein the secondary cells comprise composites.  
     
     
         25 . The method of  claim 21 , wherein the attaching comprises gluing.