Riser buoyancy system

Abstract

A frame and system for adding buoyancy to a riser used in connection with floating platforms is provided which, in some example embodiments, includes a stem attached to multiple supports which include flanges arranged to take impact and abrasion loads off an internal buoyancy module. An air management system is also provided.

What is claimed is:  
     
         1 . A buoyancy system for use with a riser, the system comprising: 
 a means for trapping air underwater,    a means for holding the means for trapping air underwater in load-transferring contact with the riser, and    at least two substantially longitudinally and substantially radially extending members connected to said means for holding, positioned and arranged to transfer side-loads to the riser.    
     
     
         2 . A system as in  claim 1  wherein the substantially longitudinal and substantially radial members are attached to the riser.  
     
     
         3 . A system as in  claim 1  wherein the substantially longitudinal and substantially radial members are attached to a riser stem.  
     
     
         4 . A system as in  claim 1  wherein the substantially longitudinal and substantially radial members are intermittently-spaced along s aid means for trapping air at locations where contact with riser guides is anticipated.  
     
     
         5 . A system as in  claim 1  wherein said substantially longitudinally and substantially radially extending members include flanges.  
     
     
         6 . A system as in  claim 5  wherein said flanges include a wear-resistant material on the surface of the flanges.  
     
     
         7 . A system as in  claim 1  wherein the means for trapping air underwater comprises a plurality of modules.  
     
     
         8 . A system as in  claim 7  wherein the modules comprise composite materials.  
     
     
         9 . A system as in  claim 8  wherein the modules are inserted radially between the substantially longitudinally and substantially radially extending members.  
     
     
         10 . A system as in  claim 7  wherein the means for trapping air underwater comprises a curved metal plate attached to flanges located on said substantially longitudinal and substantially radially extending members.  
     
     
         11 . A system as in  claim 1  wherein said substantially longitudinally and substantially radially extending members include flanges.  
     
     
         12 . A system as in  claim 1  further comprising third and fourth substantially longitudinally and substantially radially extending members connected to said means for holding.  
     
     
         13 . A system as in  claim 1  further comprising an air management system connected to the modules.  
     
     
         14 . A system as in  claim 1  further comprising horizontal bulkheads located at the top and bottom of the means for trapping air.