Closed system hydraulic expander

Abstract

The present invention provides an apparatus and method for expanding a first tubular against a second tubular. In one aspect, an expander tool includes a mandrel coupled to a spline assembly such that an annular space is formed between the same. Seals are placed between the mandrel and the spline assembly to retain a fluid in the annular space. The fluid may be used to actuate one or more expander members disposed on the spline assembly. The spline assembly is movably connected to a housing, which is coupled to a torque anchor. In operation, the mandrel is rotated, which, in turn, rotates the expander members. Rotation of the mandrel also causes the spline assembly to extend axially, thereby pulling a first seal closer to a second seal. As a result, the pressure in the annular space rises due to the compression of the fluid in the annular space. The rise in pressure extends the expander members into contact with the first tubular and expands the first tubular against the second tubular.

1 . An expander tool for expanding a first tubular against a second tubular, comprising: 
 a mandrel;    a first spline assembly coupled to the mandrel;    an annular space formed between the mandrel and the first spline assembly;    a first seal and a second seal for retaining fluid in the annular space, wherein moving the first seal closer to the second seal reduces the annular space;    one or more expander members disposed on the first spline assembly, the one or more expander members actuatable by a hydraulic pressure in the annular space; and    a second spline assembly coupled to the mandrel, the second spline assembly rotatably connected to the first spline assembly.    
     
     
         2 . The expander tool of  claim 1 , further comprising a torque anchor.  
     
     
         3 . The expander tool of  claim 2 , wherein the torque anchor is connected to the second spline assembly.  
     
     
         4 . The expander tool of  claim 3 , wherein the second spline assembly is threadedly coupled to the mandrel.  
     
     
         5 . The expander tool of  claim 4 , further comprising a pressure regulator.  
     
     
         6 . The expander tool of  claim 4 , wherein the first spline assembly comprises an inner spline coupled to an outer spline.  
     
     
         7 . The expander tool of  claim 4 , wherein the second spline assembly comprises an inner spline coupled to an outer spline.  
     
     
         8 . The expander tool of  claim 7 , wherein rotating the mandrel causes the second spline assembly to retract.  
     
     
         9 . The expander tool of  claim 8 , wherein extending the first spline assembly moves the first seal closer to the second seal.  
     
     
         10 . The expander tool of  claim 9 , wherein reducing the annular space actuates the one or more expander members.  
     
     
         11 . The expander tool of  claim 4 , wherein rotating the mandrel rotates the first spline assembly.  
     
     
         12 . The expander tool of  claim 11 , wherein the first spline assembly comprises an outer spline and an inner spline.  
     
     
         13 . The expander tool of  claim 12 , wherein the mandrel comprises a profile formed on an outer surface of the mandrel.  
     
     
         14 . The expander tool of  claim 13 , wherein the first seal is disposed on an inner surface of the first spline assembly and contacts the profile.  
     
     
         15 . A closed system hydraulic expander tool, comprising: 
 a rotatable tubular;    a first extendable housing coupled to the tubular;    a second housing coupled to the first extendable housing;    a torque anchor connected to the second housing, wherein rotating the tubular extends the first extendable housing;    one or more expander members disposed in the first extendable housing; and    a fluid chamber formed between the tubular and the first extendable housing, wherein extending the first extendable housing compresses the fluid chamber.    
     
     
         16 . The expander tool of  claim 15 , wherein rotating the tubular also rotates the first extendable housing.  
     
     
         17 . The expander tool of  claim 15 , wherein the first extendable housing comprises an inner tubular coupled to an outer tubular.  
     
     
         18 . The expander tool of  claim 15 , further comprising one or more seals for retaining a fluid within the fluid chamber.  
     
     
         19 . The expander tool of  claim 15 , further comprising a pressure regulator.  
     
     
         20 . The expander tool of  claim 15 , wherein extending the first extendable housing moves a first seal closer to a second seal.  
     
     
         21 . The expander tool of  claim 20 , wherein the one or more expander members are actuated using a pressure in the fluid chamber.  
     
     
         22 . The expander tool of  claim 15 , wherein the second housing comprises an extendable housing having an inner tubular at least partially disposed in an outer tubular, wherein the inner tubular is extendable from the outer tubular.  
     
     
         23 . The expander tool of  claim 22 , wherein the second housing is coupled to the first extendable housing using a bearing assembly.  
     
     
         24 . The expander tool of  claim 23 , wherein the second housing is coupled to the tubular using a threaded connection.  
     
     
         25 . The expander tool of  claim 15 , wherein the second housing comprises a tubular.  
     
     
         26 . The expander tool of  claim 25 , wherein the second housing is coupled to the first extendable housing using a threaded connection.  
     
     
         27 . The expander tool of  claim 26 , further comprising a first seal and a second seal for retaining a fluid in the fluid chamber, wherein the first seal remains static axially during operation and the second seal moves axially during operation.  
     
     
         28 . The expander tool of  claim 27 , wherein the second seal is attached to the first extendable housing.  
     
     
         29 . The expander tool of  claim 28 , wherein the first extendable housing comprises an inner tubular at least partially disposed in an outer tubular, wherein the inner tubular is extendable from the outer tubular  
     
     
         30 . A method for expanding a first tubular against a second tubular, comprising: 
 rotating a mandrel;    rotating one or more expander members;    advancing a first seal axially relative to a second seal;    increasing a pressure in a fluid chamber to actuate the one or more expander members;    extending the one or more expander members radially against the first tubular; and    expanding the first tubular against the second tubular.    
     
     
         31 . The method of  claim 30 , further comprising regulating the pressure in the fluid chamber.  
     
     
         32 . The method of  claim 30 , further comprising anchoring the first tubular prior to rotating the mandrel.  
     
     
         33 . The method of  claim 32 , wherein the one or more expander members are disposed on a first spline assembly.  
     
     
         34 . The method of  claim 33 , wherein the first spline assembly is rotatably connected to a second spline assembly.  
     
     
         35 . The method of  claim 34 , wherein the second spline assembly is connected to a torque anchor.