Riser for Coil Tubing/Wire Line Injection

Abstract

The present invention is directed to a system including a self supporting riser (SSR) which is connected to a well to provide fluid communication to fossil hydrocarbon reservoirs deep below the seafloor. The SSR is constructed of a plurality of joints comprising regular joints and specialty joints that define the SSR and are selected to optimize the SSR for a well in a specific location. A unique aspect of the invention is further directed to a small vessel subject to high vessel motions that permits a coil tubing/wire line system to be mounted on a stabilizer system mounted on the vessel. The riser extension that connects the vessel to the self supporting riser preferably has a telescopic joint/section that is designed for the heave of the vessel.

1 . A stabilizer system for a vessel subject to high vessel motions of heave, pitch and roll comprising:
 a heave platform adapted for attachment to said vessel,   a pitch and roll frame;   two or more pitch and roll compensation cylinders attached to said frame, each said cylinder having a compliant coupling on each end of said cylinder, one coupling attached to said frame and the coupling at the other end of said cylinder attached to said platform.   
     
     
         2 . A stabilizer system according to  claim 1  wherein each pitch and roll compensation cylinder is attached to said frame. 
     
     
         3 . A hydraulic circuit for said pitch and roll compensation cylinders of a stabilizer system according to  claim 2  comprising:
 a pump in said circuit for adding a fixed volume of fluid to the trapped fixed volume of fluid shared by the load bearing chambers of said cylinders; and 
 means to maintain said fixed volume of fluid between said load bearing chambers of said cylinders, wherein when increased pressure occurs in one or more of said cylinder chambers, fluid flows to the other cylinder chambers. 
 
     
     
         4 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a moon pool comprising:
 a stabilizer system attached to said vessel comprising:   a platform attached to said vessel placing said platform over said moon pool;   a pitch and roll stabilized frame;   two or more pitch and roll compensation cylinders attached to said frame, each cylinder having a compliant coupling on each end of said cylinder, one coupling attached to said frame and the coupling at the other end of cylinder attached to said platform.   
     
     
         5 . A small sea vessel according to  claim 4  wherein the load bearing chambers of said pitch and roll compensation cylinders are attached to said frame. 
     
     
         6 . A small sea vessel according to  claim 4  wherein said pitch and roll frame is stabilized in said moon pool. 
     
     
         7 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a moon pool comprising:
 a riser vessel interface system including   a stabilizer system attached to said vessel over said moon pool; and   a riser extension connected to said stabilizer system, said riser extension adapted to be connected to a self supporting riser.   
     
     
         8 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a porch extending beyond the deck comprising:
 a stabilizer system attached to said vessel including:   a pitch and roll stabilized frame; and   two or more pitch and roll compensation cylinders attached to said frame, each cylinder having a compliant coupling on each end of said cylinder, one coupling attached to said frame and the coupling at the other end of cylinder attached to said platform.   
     
     
         9 . A small sea vessel according to  claim 4  further comprising:
 an injector set on said pitch and roll frame. 
 
     
     
         10 . A small sea vessel according to  claim 9  wherein said injector is a coil tubing injector. 
     
     
         11 . A small sea vessel according to  claim 10  further including
 a coil tubing reel positioned near said work surface. 
 
     
     
         12 . A small sea vessel according to  claim 11  further comprising:
 a riser extension secured to said pitch and roll frame, said riser extension aligned with said injector whereby the coil tubing injected by said injector passes through said riser extension. 
 
     
     
         13 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a work surface over exposed water comprising:
 a stabilizer system attached to said vessel over said exposed water including a pitch and roll frame; and   a riser extension connected to said stabilizer system, said riser extension connected to a self supporting riser.   
     
     
         14 . A small sea vessel according to  claim 13  further comprising:
 a framework set on said pitch and roll frame holding an injector. 
 
     
     
         15 . A small sea vessel according to  claim 14  wherein said injector is a coil tubing injector. 
     
     
         16 . A small sea vessel according to  claim 15  further including
 a coil tubing reel positioned near said moon pool. 
 
     
     
         17 . A small sea vessel according to  claim 16  further including
 a straightener near said reel for changing the radius of coil tubing on said reel to an arc for entry to said coil tubing injector. 
 
     
     
         18 . A small sea vessel according to  claim 17  further including
 a straightener near the top of said coil tubing injector for changing the radius of coil tubing in said arc for entry of said coil tubing into the riser extension. 
 
     
     
         19 . An intervention method for running coil tubing into a well on the seafloor wherein a Self Supporting Riser (SSR) is attached to the well's seafloor infrastructure and a vessel according to  claim 18  which comprises
 operating said coil tubing injector for running coil tubing into said well. 
 
     
     
         20 . An intervention method comprising:
 running a coil tubing into a well on the seafloor through a self supporting riser attached on the wellhead by a coil tubing injector mounted on a small sea vessel subject to high vessel motions of heave, pitch and roll.   
     
     
         21 . An intervention method according to  claim 20  wherein said coil tubing is drawn off a reel by said coil tubing injector forming an arc between said reel and said coil tubing injector. 
     
     
         22 . An intervention method according to  claim 20  wherein said coil tubing is straightened as said tubing is drawn off said reel to form said arc and is straightened by said injector to pass though said self supporting riser. 
     
     
         23 . An intervention method according to  claim 20  wherein the heave of the vessel is through a telescopic joint/section in the riser extension connecting the vessel to the self supporting riser. 
     
     
         24 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a moon pool comprising:
 a stabilizer system attached to said vessel over said moon pool including;   a platform attached to said vessel;   a pitch and roll stabilized frame; and   two or more pitch and roll compensation cylinders attached to said frame, each cylinder having a compliant coupling on each end of said cylinder, one coupling attached to said frame and the coupling at the other end of cylinder attached to said platform; and   a riser extension connected to said stabilizer system, said riser extension including a telescopic joint and adapted to be connected to a self supporting riser.   
     
     
         25 . A small sea vessel subject to high vessel motions of heave, pitch and roll and having a moon pool according to  claim 24  further including:
 a coil tubing injector mounted on said pitch and roll stabilized frame. 
 
     
     
         26 . A small sea vessel according to  claim 24  wherein said telescopic joint has a chamber in which said riser extension is allowed to extend and retract as the vessel heaves. 
     
     
         27 . A small sea vessel according to  claim 26  further including a line to said chamber wherein the pressure in said chamber may be increased or decreased to pull on or push against said self supporting riser.