Production riser with pre-formed curves for accommodating vessel motion

Abstract

A system for establishing a fluid communication between a floating-body and a wellhead is provided. The system comprises a means for fluidly connecting the floating-body and the wellhead that defines a major axis essentially extending from about the floating-body to about the wellhead. The system further comprises a means for absorbing and releasing energy in response to the heave and surge of the floating-body that flexes in a direction essentially parallel to the major axis. An apparatus is also provided for establishing a fluid connection between a floating-body and a wellhead that is fixed to the seafloor. The apparatus comprises a riser pipe and a series of pre-formed curves in the riser pipe that defines a substantially linear axis between the floating-body and the wellhead.

I claim:  
     
         1 . A system for establishing a fluid communication between a floating-body and a wellhead, the system comprising: 
 a means for fluidly connecting the floating-body and the wellhead, wherein said means for fluidly connecting defines a major axis essentially extending from about the floating-body to about the wellhead; and    a means for absorbing and releasing energy in response to the heave and surge of the floating-body, wherein said means for absorbing and releasing energy flexes in a direction essentially parallel to the major axis;    wherein the means for fluidly connecting comprises a steel riser;    wherein the means for storing and releasing comprises a series of pre-formed curves in the steel riser; and    wherein the series of pre-formed curves comprise a series of single-planar, pre-formed curves in the riser.    
     
     
         2 . A system as in  claim 1  wherein the series of single-planar curves comprise arcs having a substantially constant radius of curvature.  
     
     
         3 . A system as in  claim 1  wherein the series of single-planar curves comprises sinusoidal shaped curves.  
     
     
         4 . A system for establishing a fluid communication between a floating-body and a wellhead, the system comprising: 
 a means for fluidly connecting the floating-body and the wellhead, wherein said means for fluidly connecting defines a major axis essentially extending from about the floating-body to about the wellhead; and    a means for absorbing and releasing energy in response to the heave and surge of the floating-body, wherein said means for absorbing and releasing energy flexes in a direction essentially parallel to the major axis;    wherein the means for fluidly connecting comprises a steel riser;    wherein the means for storing and releasing comprises a series of pre-formed curves in the steel riser; and    wherein the series of pre-formed curves comprise a series of multi-planar, pre-formed curves in the riser.    
     
     
         5 . A system as in  claim 4  wherein the series of multi-planar curves comprise arcs having a substantially constant radius of curvature.  
     
     
         6 . A system as in  claim 4  wherein the series of multi-planar curves comprises sinusoidal shaped curves.  
     
     
         7 . A system as in  claim 6  wherein the series of multi-formed curves comprise helical pre-formed curves.