Co-linear tensioner and methods of installing and removing same

Abstract

The invention is directed to a tensioner for providing linear and angular movement of a drilling or production facility relative to a conduit or riser secured to the tensioner and to the wellhead in offshore operations. The tensioner compensates for vessel motion induced by wave action and heave and maintains a variable tension to the riser string alleviating the potential for compression and thus buckling or failure of the riser string. The tensioner of the present invention preferably includes at least one top load plate that facilitates easy and quick installation and removal of the tensioner from the rig floor of the vessel or platform. The tensioner also facilitates the placement of at least one piece of equipment disposed within the area formed by the tensioning cylinders. The tensioner may also include one or more pieces of equipment, e.g., a rotary table, integrally formed with the tensioner to further increase the ease and speed of installation and removal of the tensioner from the rig floor. Methods for installing and removing tensioners from the rig floor are also disclosed.

1 - 19 . (canceled)  
   
   
       20 . A tensioner comprising: 
 at least one top load plate having at least one blow-out preventer formed integral with the at least one top load plate, at least one upper swivel assembly, at least one tensioning cylinder plate, at least one tensioning cylinder, and a base, the at least one tensioning cylinder being in communication with the at least one tensioning cylinder plate and with the base; 
 wherein the at least one top load plate, the at least one upper swivel assembly, the at least one tensioning cylinder plate, the at least one tensioning cylinder, and the base are assembled to form a unitary, co-linear tensioner.  
   
   
   
       21 . The tensioner of  claim 20 , wherein the base is in communication with at least one extension rod and at least one extension platform.  
   
   
       22 . The tensioner of  claim 21 , wherein at least one piece of equipment is disposed on the extension platform.  
   
   
       23 . The tensioner of  claim 22 , wherein the at least one piece of equipment includes at least one blowout preventer.  
   
   
       24 . The tensioner of  claim 20 , wherein each of the at least one tensioning cylinders includes a tensioning cylinder casing having a length and at least one fluid control port.  
   
   
       25 . The tensioner of  claim 24 , wherein each of the at least one fluid control ports is disposed along the length of each of the tensioning cylinder.  
   
   
       26 . The tensioner of  claim 24 , wherein at least one of the at least one fluid control ports is disposed along the length of each of the tensioning cylinders.  
   
   
       27 . A tensioner comprising: 
 at least one top load plate having at least one rotary table formed integral with the at least one top load plate, at least one upper swivel assembly, at least one tensioning cylinder plate, at least one tensioning cylinder, and a base, the at least one tensioning cylinder being in communication with the at least one tensioning cylinder plate and with the base; 
 wherein the at least one top load plate, the at least one upper swivel assembly, the at least one tensioning cylinder plate, the at least one tensioning cylinder, and the base are assembled to form a unitary, co-linear tensioner.  
   
   
   
       28 . The tensioner of  claim 27 , wherein the base is in communication with at least one extension rod and at least one extension platform.  
   
   
       29 . The tensioner of  claim 28 , wherein at least one piece of equipment is disposed on the extension platform.  
   
   
       30 . The tensioner of  claim 29 , wherein the at least one piece of equipment includes at least one blowout preventer.  
   
   
       31 . The tensioner of  claim 27 , wherein each of the at least one tensioning cylinders includes a tensioning cylinder casing having a length and at least one fluid control port.  
   
   
       32 . The tensioner of  claim 31 , wherein each of the at least one fluid control ports is disposed along the length of each of the tensioning cylinder.  
   
   
       33 . The tensioner of  claim 31 , wherein at least one of the at least one fluid control ports is disposed along the length of each of the tensioning cylinders.  
   
   
       34 . A tensioner comprising: 
 at least one top load plate having at least one snubbing unit formed integral with the at least one top load plate, at least one upper swivel assembly, at least one tensioning cylinder plate, at least one tensioning cylinder, and a base, the at least one tensioning cylinder being in communication with the at least one tensioning cylinder plate and with the base; 
 wherein the at least one top load plate, the at least one upper swivel assembly, the at least one tensioning cylinder plate, the at least one tensioning cylinder, and the base are assembled to form a unitary, co-linear tensioner.  
   
   
   
       35 . The tensioner of  claim 34 , wherein the base is in communication with at least one extension rod and at least one extension platform.  
   
   
       36 . The tensioner of  claim 35 , wherein at least one piece of equipment is disposed on the extension platform.  
   
   
       37 . The tensioner of  claim 36 , wherein the at least one piece of equipment includes at least one blowout preventer.  
   
   
       38 . The tensioner of  claim 34 , wherein each of the at least one tensioning cylinders includes a tensioning cylinder casing having a length and at least one fluid control port.  
   
   
       39 . The tensioner of  claim 38 , wherein each of the at least one fluid control ports is disposed along the length of each of the tensioning cylinder.  
   
   
       40 . The tensioner of  claim 38 , wherein at least one of the at least one fluid control ports is disposed along the length of each of the tensioning cylinders.