Subsea Intervention Riser System

Abstract

The invention comprises a multi-component system for subsea intervention. The system comprises a lower riser component which is held vertical by a buoyance element and an upper riser system. The upper riser system is a continuous, enjoined conduit with sufficient flexibility to absorb the motion of the deployment vessel without adversely affecting the function of the intervention system.

1 . A subsea intervention system comprising:
 (a) a lower riser component;   (b) a first buoyancy element attached to the upper end of said lower riser component;   (c) an upper riser component extending between the upper end of said lower riser component and a surface vessel, said upper riser component having sufficient flexibility to absorb the motion of said surface vessel without adversely affecting the operation of said intervention system;   (d) a second buoyancy element attached to said upper riser system, wherein said upper riser component comprises continuous un-jointed, unbonded composite pipe.   
   
   
       2 . The intervention system of  claim 1  wherein said lower and upper user components comprise multi bore risers. 
   
   
       3 . The intervention system of  claim 1  further comprising a disconnect system between said upper and lower riser components. 
   
   
       4 . The intervention system of  claim 1  wherein said lower riser component is connected to a Xmas tree. 
   
   
       5 . The intervention system of  claim 4  further comprising a Blowout Preventer placed between said lower riser component and said Xmas tree. 
   
   
       6 . The intervention system of  claim 1  further comprising an external conduit mounted to said upper and lower riser components. 
   
   
       7 . The intervention system of  claim 1  wherein the upper and lower riser components are lined. 
   
   
       8 . The intervention system of  claim 1  further comprising a pressure activated sealing system at the bottom of the upper riser component. 
   
   
       9 . The intervention system of  claim 1  further comprising a motion compensation system located between the upper and lower riser components. 
   
   
       10 . A subsea intervention system comprising:
 (a) a lower riser component;   (b) an upper riser component extending between said lower riser component and a surface vessel, said upper riser component comprising continuous, un-jointed, unbonded composite pipe;   
   
   
       11 . The intervention system of  claim 10  wherein the upper riser component has sufficient flexibility to absorb the motion of said surface vessel without adversely affecting the operation of said intervention system. 
   
   
       12 . The intervention system of  claim 10  wherein the said upper and lower riser components comprise two or more bores. 
   
   
       13 . The intervention system of  claim 10  further comprising a disconnect system located between said upper and lower riser components. 
   
   
       14 . The intervention system of  claim 10  further comprising a disconnect system between said upper and lower riser components. 
   
   
       15 . The intervention system of  claim 10  wherein said lower riser component is connected to a Xmas tree. 
   
   
       16 . The intervention system of  claim 15  further comprising a Blowout Preventer placed between said lower riser component and said Xmas tree. 
   
   
       17 . The intervention system of  claim 10  further comprising an external conduit mounted to said upper and lower riser components. 
   
   
       18 . The intervention system of  claim 10  wherein the upper and lower riser components are lined. 
   
   
       19 . The intervention system of  claim 10  further comprising a pressure activated sealing system at the bottom of the upper riser component. 
   
   
       20 . The intervention system of  claim 10  further comprising a motion compensation system located between the upper and lower riser components. 
   
   
       21 . The intervention system of  claim 10  where in the lower riser component comprises continuous/un-jointed unbonded composite pipe.