Subsea telescoping and rotatable sub

Abstract

A subsea telescoping and rotatable connector or sub is coupled into a riser. The sub includes two coupled bodies that are both axially and rotatably moveable relative to each other such that the sub enables the riser to move axially in response to tension or compression in the riser and rotate in response to surface vessel rotation or other torques. The sub expands and contracts in response to the tension or compression in the riser, and swivels in response to surface vessel rotation.

What is claimed is: 
     
         1 . A subsea riser connector comprising:
 a first body telescopically received within a second body;   an inner flow bore through the first and second bodies;   a chamber disposed between the first and second bodies;   a sliding seal disposed in the chamber and slidingly engaged with the first and second bodies; and   a cylindrical interface between the first body and the second body to enable relative axial movement and relative rotational movement between the first and second bodies.   
     
     
         2 . The connector of  claim 1 , wherein the sliding seal separates the chamber into a first chamber portion and a second chamber portion. 
     
     
         3 . The connector of  claim 2 , wherein the first chamber portion includes a port in fluid communication with the inner flow bore. 
     
     
         4 . The connector of  claim 3 , wherein the second chamber portion includes a port in fluid communication with an exterior of the first and second bodies. 
     
     
         5 . The connector of  claim 3 , wherein an effective area A i  at an end of the first body disposed in a flow bore of the second body receives a pressure P i  in the inner flow bore. 
     
     
         6 . The connector of  claim 5 , wherein an annular area A A  in the first chamber portion receives the pressure P i  from the inner flow bore. 
     
     
         7 . The connector of  claim 6 , wherein the effective area A i  is substantially equal to the annular area A A . 
     
     
         8 . The connector of  claim 6 , wherein the annular area A A  is greater than the effective area 
     
     
         9 . The connector of  claim 6 , wherein the first chamber portion includes a stop. 
     
     
         10 . The connector of  claim 6 , wherein the second chamber portion includes a stop. 
     
     
         11 . The connector of  claim 6 , wherein the first chamber portion includes a biasing spring. 
     
     
         12 . The connector of  claim 2 , wherein the first chamber portion includes a port having a one-way valve disposed between the first chamber portion and an exterior of the first and second bodies, wherein the second chamber portion includes a port in fluid communication with the exterior of the first and second bodies, wherein an effective area A i  at an end of the first body disposed in a flow bore of the second body receives a pressure P i  in the inner flow bore, and wherein the one-way valve is configured to communicate a pressurized fluid to the first chamber portion and bias the connector. 
     
     
         13 . The connector of  claim 1 , wherein the cylindrical interface further comprises a first cylindrical surface at an end of the first body mating with a second cylindrical surface in a flow bore of the second body. 
     
     
         14 . The connector of  claim 13 , further comprising a sliding seal disposed between the first and second cylindrical surfaces. 
     
     
         15 . The connector of  claim 13 , wherein the first cylindrical surface is axially moveable and rotatable relative to the mating second cylindrical surface. 
     
     
         16 . The connector of  claim 13 , wherein the cylindrical interface further comprises a third cylindrical surface on the first body opposite the chamber from the first cylindrical surface, the third cylindrical surface mating with a fourth cylindrical surface in the second body opposite the chamber from the second cylindrical surface. 
     
     
         17 . The connector of  claim 16 , wherein the third cylindrical surface is axially moveable and rotatable relative to the mating fourth cylindrical surface. 
     
     
         18 . A subsea riser system comprising:
 a first body telescopically received within a second body;   a riser coupled to the first and second bodies;   an inner flow bore through the first and second bodies, the inner flow bore in fluid communication with an inner flow bore of the riser;   a chamber disposed between the first and second bodies;   a sliding seal disposed in the chamber and slidingly engaged with the first and second bodies; and   a cylindrical interface between the first body and the second body to enable relative axial movement and relative rotational movement between the first and second bodies.   
     
     
         19 . The riser system of  claim 18 , further comprising a biasing force in the chamber to put the riser in tension. 
     
     
         20 . The riser system of  claim 18 , wherein the cylindrical interface further comprises a plurality of mating cylindrical surfaces between the first and second bodies wherein each mating cylindrical surface is axially moveable and rotatable relative to an opposing mating cylindrical surface. 
     
     
         21 . A method of connecting to a subsea riser comprising:
 telescopically receiving a first body within a second body;   coupling the first and second bodies to a subsea riser;   axially moving the first and second bodies relative to each other at a cylindrical interface disposed between the first and second bodies in response to a tension or compression force on the riser; and   rotationally moving the first and second bodies relative to each other at the cylindrical interface in response to a torque on the riser.   
     
     
         22 . The method of  claim 21 , further comprising communicating a fluid through an inner flow bore of the first and second bodies. 
     
     
         23 . The method of  claim 22 , further comprising communicating the fluid to a first chamber portion of a chamber between the first and second bodies. 
     
     
         24 . The method of  claim 23 , further comprising pressure balancing the first and second bodies in response to communicating the fluid to the first chamber portion. 
     
     
         25 . The method of  claim 23 , further comprising communicating an exterior fluid to a second chamber portion of the chamber. 
     
     
         26 . The method of  claim 21 , wherein the cylindrical interface includes multiple sets of mating surfaces, and axially moving and rotationally moving each set of mating surfaces. 
     
     
         27 . The method of  claim 22 , further comprising biasing the first and second bodies toward each other to place the subsea riser in tension.