Apparatus and method for performing an intervention in a riser

Abstract

An apparatus and method are provided for performing an intervention in a flexible riser that extends between topside and subsea locations. The method generally includes providing a composite tube and inserting a leading end of the composite tube into the flexible riser so that the composite tube extends through the flexible riser from the topside location toward the subsea location. The composite tube can be configured to deliver a material into the flexible riser, e.g., to remove a blockage formed in the riser.

What is claimed is:  
     
         1 . A method of performing an intervention in a flexible riser extending between topside and subsea locations, the method comprising:
 providing a composite tube defining a leading end, the composite tube being formed of a composite material; and   inserting the leading end of the composite tube into the flexible riser such that the composite tube extends through the flexible riser from the topside location toward the subsea location and the composite tube is configured to deliver a material therethrough and into the flexible riser.   
     
     
         2 . A method according to  claim 1 , wherein the composite tube is formed of a composite material comprising a laminate reinforcement material impregnated with a matrix material. 
     
     
         3 . A method according to  claim 1 , wherein the composite tube is formed of a composite material comprising carbon fiber impregnated with a polymer. 
     
     
         4 . A method according to  claim 1 , wherein the composite tube has an internal diameter of between 0.5 inch and 3 inches. 
     
     
         5 . A method according to  claim 1 , wherein the inserting step comprises inserting the leading end of the composite tube to a touchdown point of the riser such that the composite tube extends from the topside location to the subsea location. 
     
     
         6 . A method according to  claim 1 , wherein the inserting step comprises inserting the composite tube through at least 1000 feet of the riser such that the tube extends at least 1000 feet below the topside location. 
     
     
         7 . A method according to  claim 1 , further comprising delivering a material through the composite tube from the topside location to the leading end of the composite tube such that the material exits the composite tube at the leading end in the riser. 
     
     
         8 . A method according to  claim 7 , wherein the delivering step comprising delivering a chemical to the flexible riser to remove a blockage in the riser. 
     
     
         9 . A method according to  claim 7 , wherein the delivering step comprising delivering a material to the flexible riser to remove a blockage in the riser, the material being at least one of the group consisting of a solvent and a hydrocarbon that is lighter than a fluid in the riser. 
     
     
         10 . A method according to  claim 8 , wherein the inserting step comprises inserting the leading end of the composite tube to a blockage in the riser such that the chemical is provided to the blockage and removes the blockage. 
     
     
         11 . An apparatus configured to perform the method of  claim 1 .