Apparatus for axially displacing and tensioning a string of production tubing in a well bore

Abstract

A tensioning tool assembly for supporting a string of oil production piping extending through a well bore includes an outer barrel and a telescoping inner mandrel slidably positioned within the outer barrel. The inner mandrel defines a plurality of axially-spaced slots configured to receive protruding members extending from the outer barrel to fix the relative axial position of the inner mandrel and outer barrel. In this manner, a string of production tubing may be axially displaced by moving inner mandrel to the desired axial position or tension and then rotating inner mandrel to lock the tensioning tool assembly and the attached production tubing. The inner mandrel may further define threaded features for attaching a pull rod and/or a central passageway for supplying fluid to control well pressures.

What is claimed is: 
     
         1 . A tensioning tool assembly for supporting a string of oil production piping extending through a well bore, the tensioning tool comprising:
 an outer barrel defining an axial direction, a radial direction, and a circumferential direction, the outer barrel extending between an upper end and a lower end along the axial direction; and   a telescoping inner mandrel slidably positioned within the outer barrel, the inner mandrel extending between a first end and a second end along the axial direction, the inner mandrel defining a coupling feature configured for engaging a complementary feature defined on a pull rod such that the pull rod is configured for selectively engaging and moving the inner mandrel along the axial direction.   
     
     
         2 . The tensioning tool assembly of  claim 1 , wherein the coupling feature comprises mandrel threads defined on an inner surface of the inner mandrel and the complementary feature comprises pull rod threads defined on a distal end of the pull rod. 
     
     
         3 . The tensioning tool assembly of  claim 1 , wherein the pull rod defines a central passageway in fluid communication with an internal passageway of the inner mandrel. 
     
     
         4 . The tensioning tool assembly of  claim 1 , wherein the relative axial positioning and the relative circumferential positioning of the pull rod and the inner mandrel are fixed when the coupling feature engages the complementary feature. 
     
     
         5 . The tensioning tool assembly of  claim 1 , wherein the outer barrel comprises:
 a first barrel defining a male threaded portion; and   a second barrel defining a female threaded portion, the male threaded portion and the female threaded portion being engaged to join the first barrel and the second barrel.   
     
     
         6 . The tensioning tool assembly of  claim 5 , wherein a joint is defined where the male threaded portion engages the female threaded portion, the joint defining a joint thickness that is substantially equal to a wall thickness of the first barrel and the second barrel. 
     
     
         7 . The tensioning tool assembly of  claim 1 , wherein the inner mandrel defines one or more circumferential grooves on an outer surface proximate the first end of the inner mandrel, the tensioning tool assembly further comprising one or more resilient seals positioned within the circumferential grooves to provide a fluid seal between the inner mandrel and the outer barrel. 
     
     
         8 . The tensioning tool assembly of  claim 1 , wherein the inner mandrel defines a plurality of slots extending substantially along the circumferential direction around the inner mandrel, the plurality of slots being spaced apart along the axial direction, and wherein the outer barrel defines one or more protruding members proximate the lower end of the outer barrel, the protruding members being configured for receipt within the slots to fix an axial position of the inner mandrel within the outer barrel. 
     
     
         9 . The tensioning tool assembly of  claim 8 , wherein the plurality of slots extend at an angle relative to the circumferential direction. 
     
     
         10 . The tensioning tool assembly of  claim 9 , wherein the angle is between about 1 and 20 degrees. 
     
     
         11 . The tensioning tool assembly of  claim 8 , wherein an outer surface of the inner mandrel defines an elongated flat recess to define a radial gap between the inner mandrel and the outer barrel, the protruding members defining a height that is less than the radial gap such that the inner mandrel slidable along the axial direction relative to the outer barrel when the protruding members are positioned within the radial gap. 
     
     
         12 . The tensioning tool assembly of  claim 11 , wherein the inner mandrel defines one or more locking recesses proximate the first end of the inner mandrel, the locking recesses being configured for engaging the protruding members to prevent the inner mandrel from rotating within the outer barrel. 
     
     
         13 . The tensioning tool assembly of  claim 8 , wherein the plurality of slots comprises six slots, each of the six slots being spaced apart from adjacent slots by approximately 12 centimeters along the axial direction. 
     
     
         14 . The tensioning tool assembly of  claim 1 , wherein the upper end of the outer barrel is threaded for receipt in a tubing hanger mounted to a wellhead. 
     
     
         15 . A tensioning tool assembly for supporting a string of oil production piping extending through a well bore, the tensioning tool comprising:
 an outer barrel defining an axial direction, a radial direction, and a circumferential direction, the outer barrel comprising a first barrel defining a male threaded portion and a second barrel defining a female threaded portion, the male threaded portion and the female threaded portion being engaged to join the first barrel and the second barrel; and   a telescoping inner mandrel slidably positioned within the outer barrel, the inner mandrel extending between a first end and a second end along the axial direction, the inner mandrel defining a coupling feature configured for engaging a complementary feature defined on a pull rod such that the pull rod is configured for selectively engaging and moving the inner mandrel along the axial direction.   
     
     
         16 . The tensioning tool assembly of  claim 15 , wherein a joint is defined where the male threaded portion engages the female threaded portion, the joint defining a joint thickness that is substantially equal to a wall thickness of the first barrel and the second barrel. 
     
     
         17 . The tensioning tool assembly of  claim 15 , wherein the coupling feature comprises mandrel threads defined on an inner surface of the inner mandrel and the complementary feature comprises pull rod threads defined on a distal end of the pull rod, and wherein the relative axial positioning and the relative circumferential positioning of the pull rod and the inner mandrel are fixed when the pull rod threads engage the mandrel threads. 
     
     
         18 . The tensioning tool assembly of  claim 15 , wherein the pull rod defines a central passageway in fluid communication with an internal passageway of the inner mandrel. 
     
     
         19 . The tensioning tool assembly of  claim 15 , wherein the inner mandrel defines one or more circumferential grooves on an outer surface proximate the first end of the inner mandrel, the tensioning tool assembly further comprising one or more resilient seals positioned within the circumferential grooves to provide a fluid seal between the inner mandrel and the outer barrel. 
     
     
         20 . The tensioning tool assembly of  claim 15 , wherein the inner mandrel defines a plurality of slots extending substantially along the circumferential direction around the inner mandrel, the plurality of slots being spaced apart along the axial direction, and wherein the outer barrel defines one or more protruding members proximate a lower end of the outer barrel, the protruding members being configured for receipt within the slots to fix an axial position of the inner mandrel within the outer barrel.