Deck mounted pull riser tensioning system

Abstract

A deck mounted pull riser tensioning system for a floating platform or vessel includes at least two cylinders having a cylinder body supported at an upper or lower end on a deck or tensioner support structure of the platform or vessel in spaced apart relation with the cylinder rods extending downwardly from the cylinder body, or vice versa. A load structure member is connected to lower ends of the cylinder rods or bodies and has an opening therethrough for receiving a portion of a riser extending from the seafloor. A vertically adjustable riser attachment supported on the load structure member over the opening attaches to a portion of the riser extending through the opening and generally centrally between the cylinders. The cylinders pull upwardly on the load structure member to exert an upward tensioning force on the riser at the location of the riser attachment.

1 . A deck mounted pull riser tensioning system for a floating platform or vessel, comprising: 
 at least two hydraulic or pneumatic cylinders having a cylinder body supported at a lower end on a tensioner support structure of said platform or vessel in spaced apart relation and having cylinder rods extending downwardly from said cylinder body lower ends through the deck;    a load structure member connected to lower ends of said cylinder rods and having an opening therethrough for receiving a portion of a riser extending from the seafloor; and    a vertically adjustable riser attachment supported on said load structure member over said opening for attachment to a portion of a riser extending through said load structure opening and generally centrally between said cylinders, said riser attachment adjustably positioned on the riser to accommodate variations in riser stack-up relative to the seafloor;    said cylinders, when activated, pulling upwardly on said load structure member to exert an upward force on the riser at the location of the riser attachment.    
   
   
       2 . The deck mounted pull riser tensioning system according to  claim 1 , further comprising: 
 riser centralizer means disposed above said riser attachment for receiving and guiding an upper portion of the riser between said cylinders.    
   
   
       3 . The deck mounted pull riser tensioning system according to  claim 1 , wherein 
 said cylinders are disposed substantially vertical with respect to the deck on which they are supported.    
   
   
       4 . The deck mounted pull riser tensioning system according to  claim 1 , further comprising: 
 riser guide means disposed below said load structure member for receiving and providing lateral guidance and centralization of the riser below said load structure member.    
   
   
       5 . The deck mounted pull riser tensioning system according to  claim 1 , further comprising: 
 upper guide means adapted for connection to an upper end portion of the riser and having outer ends movably engaged with said cylinders for providing lateral guidance and centralization of the upper end portion of the riser relative to said cylinders.    
   
   
       6 . The deck mounted pull riser tensioning system according to  claim 5 , wherein 
 the upper end portion of the riser includes a Christmas tree and/or a blowout preventer (BOP) assembly; and    said upper guide means is adapted for connection to the Christmas tree and/or blowout preventer (BOP) assembly has outer ends movably engaged with said cylinders for providing lateral guidance and centralization of the Christmas tree and/or blowout preventer (BOP) assembly relative to said cylinders.    
   
   
       7 . The deck mounted pull riser tensioning system according to  claim 1 , wherein 
 said riser attachment is supported on said load structure by a gimbal support.    
   
   
       8 . The deck mounted pull riser tensioning system according to  claim 1 , wherein 
 said cylinders are supported on said deck so as to substantially prevent relative rotational movement between said cylinder body lower ends and the deck on which they are supported.    
   
   
       9 . The deck mounted pull riser tensioning system according to  claim 1 , wherein 
 said cylinders are supported on said deck so as to allow relative rotational movement between said cylinder body lower ends and the deck on which they are supported.    
   
   
       10 . A deck mounted pull riser tensioning system for a floating platform or vessel, comprising: 
 at least two hydraulic or pneumatic cylinders having a cylinder body supported at an upper end in a generally vertical orientation beneath a tensioner support structure of said platform or vessel in a spaced apart relation and having cylinder rods extending downwardly from lower ends of said cylinder body;    a load structure member connected to lower ends of said cylinder rods and having an opening therethrough for receiving a portion of a riser extending from the seafloor; and    a vertically adjustable riser attachment supported on said load structure member over said opening for attachment to a portion of a riser extending through said load structure opening and generally centrally between said cylinders, said riser attachment adjustably positioned on the riser to accommodate variations in riser stack-up relative to the seafloor;    said cylinders, when activated, pulling upwardly on said load structure member to exert an upward force on the riser at the location of the riser attachment.    
   
   
       11 . The deck mounted pull riser tensioning system according to  claim 10 , further comprising: 
 riser centralizer means disposed above said riser attachment for receiving and guiding an upper portion of the riser between said cylinders.    
   
   
       12 . The deck mounted pull riser tensioning system according to  claim 10 , further comprising: 
 riser guide means disposed below said load structure member for receiving and providing lateral guidance and centralization of the riser below said load structure member.    
   
   
       13 . The deck mounted pull riser tensioning system according to  claim 10 , further comprising: 
 upper guide means adapted for connection to an upper end portion of the riser and having outer ends movably engaged with said cylinders for providing lateral guidance and centralization of the upper end portion of the riser relative to said cylinders.    
   
   
       14 . The deck mounted pull riser tensioning system according to  claim 13 , wherein 
 the upper end portion of the riser includes a Christmas tree and/or a blowout preventer (BOP) assembly; and    said upper guide means is adapted for connection to the Christmas tree and/or blowout preventer (BOP) assembly has outer ends movably engaged with said cylinders for providing lateral guidance and centralization of the Christmas tree and/or blowout preventer (BOP) assembly relative to said cylinders.    
   
   
       15 . The deck mounted pull riser tensioning system according to  claim 10 , wherein 
 said riser attachment is supported on said load structure by a gimbal support.    
   
   
       16 . A deck mounted pull riser tensioning system for a floating platform or vessel, comprising: 
 at least two hydraulic or pneumatic cylinders having a cylinder body supported on a tensioner support structure of said platform or vessel in spaced apart relation and having cylinder rods extending downwardly from said cylinder body lower ends through said tensioner support structure;    a load structure member connected to lower ends of said cylinder rods and having an opening therethrough for receiving a portion of a riser extending from the seafloor; and    a vertically adjustable riser attachment supported on said load structure member over said opening for attachment to a portion of a riser extending through said load structure opening and generally centrally between said cylinders, said riser attachment adjustably positioned on the riser to accommodate variations in riser stack-up relative to the seafloor;    said cylinders, when activated, pulling upwardly on said load structure member to exert an upward force on the riser at the location of the riser attachment.    
   
   
       17 . A deck mounted pull riser tensioning system for a floating platform or vessel, comprising: 
 at least two hydraulic or pneumatic cylinders having a cylinder rod supported at an upper end in a generally vertical orientation beneath a tensioner support structure of said platform or vessel in a spaced apart relation and having a cylinder body extending downwardly from said cylinder rod;    a load structure member connected to lower ends of said cylinder body and having an opening therethrough for receiving a portion of a riser extending from the seafloor; and    a vertically adjustable riser attachment supported on said load structure member over said opening for attachment to a portion of a riser extending through said load structure opening and generally centrally between said cylinders, said riser attachment adjustably positioned on the riser to accommodate variations in riser stack-up relative to the seafloor;    said cylinders, when activated, pulling upwardly on said load structure member to exert an upward force on the riser at the location of the riser attachment.