Riser assembly and method

Abstract

A riser assembly and method of providing a riser assembly for transporting production fluids from a location deep under water are disclosed. The riser assembly includes a riser comprising a flexible pipe, the riser having a hang off point which is an end of the riser that in use connects with a floating facility, and a touchdown zone which in use is a section of the riser in the region of where the riser meets the seabed or other fixed structure; and at least one buoyancy element arranged at the touchdown zone or within about 50 m of the touchdown zone of the riser to support the riser in a configuration for accommodating kinetic energy propagating along the riser from the hang off point.

1 . A riser assembly for transporting production fluids from a location deep under water, comprising:
 a riser comprising a flexible pipe, the riser having a hang off point which is an end of the riser that in use connects with a floating facility, and a touchdown zone which in use is a section of the riser in the region of where the riser meets the seabed or other fixed structure; and   at least one buoyancy element arranged at the touchdown zone or within about 50 m of the touchdown zone of the riser to support the riser in a configuration for accommodating kinetic energy propagating along the riser from the hang off point.   
     
     
         2 . A riser assembly as claimed in  claim 1 , wherein the at least one buoyancy element is arranged on the riser at a distance of between around 5 and 50 m from the seabed or other fixed structure in use. 
     
     
         3 . A riser assembly as claimed in  claim 2  wherein the at least one buoyancy element is arranged on the riser at a distance of between around 10 and 45 m from the seabed or other fixed structure in use. 
     
     
         4 . A riser assembly as claimed in  claim 3  wherein the at least one buoyancy element is arranged on the riser at a distance of between around 20 and 40 m from the seabed or other fixed structure in use. 
     
     
         5 . A riser assembly as claimed in  claim 1  wherein the at least one buoyancy element is arranged to form a sag bend in use. 
     
     
         6 . A riser assembly as claimed in  claim 1  wherein the at least one buoyancy element is arranged to form a waved configuration in use. 
     
     
         7 . A riser assembly as claimed in  claim 1  wherein the at least one buoyancy element is arranged to form a double waved configuration in use. 
     
     
         8 . A method of providing a riser assembly for transporting production fluids from a location deep under water, comprising:
 providing a riser comprising a flexible pipe, the riser having a hang off point which is an end of the riser that in use connects with a floating facility, and a touchdown zone which in use is a section of the riser in the region of where the riser meets the seabed or other fixed structure; and   providing at least one buoyancy element arranged at the touchdown zone or within about 50 m of the touchdown zone of the riser to support the riser in a configuration for accommodating kinetic energy propagating along the riser from the hang off point.   
     
     
         9 . A method as claimed in  claim 8  further comprising arranging the at least one buoyancy element on the riser at a distance of between around 5 and 50 m from the seabed or other fixed structure in use. 
     
     
         10 . A method as claimed in  claim 9  further comprising arranging the at least one buoyancy element on the riser at a distance of between around 10 and 45 m from the seabed or other fixed structure in use. 
     
     
         11 . A method as claimed in  claim 10  further comprising arranging the at least one buoyancy element on the riser at a distance of between around 20 and 40 m from the seabed or other fixed structure in use. 
     
     
         12 . A method as claimed in  claim 8  further comprising arranging the at least one buoyancy element to form a sag bend in use. 
     
     
         13 . A method as claimed in  claim 8  further comprising arranging the at least one buoyancy element to form a waved configuration in use. 
     
     
         14 . A method as claimed in  claim 8  further comprising arranging the at least one buoyancy element to form a double waved configuration in use.