Method and apparatus for treating a wellbore

Abstract

The present disclosure generally concerns the treatment of hydrocarbon-bearing formations adjacent a wellbore. In one embodiment, fracturing jobs are performed through the use of subs disposed in a casing string having profiles that interact with profiles formed on retractable keys of a tool.

1 .- 8 . (canceled) 
     
     
         9 . A downhole tool for treating a zone of interest in a wellbore, the tool including:
 a first set of outwardly biased keys disposed at a first axial location along the tool, the first set including profiles formed thereon for engaging a port sleeve having mating profiles in a surrounding port sub;   a second set of outwardly biased keys disposed at a second axial location along the tool, the second set having differently-shaped profiles formed thereon for engaging mating profiles of the port sleeve in the port sub; and   a first sleeve movable along an outer surface of the tool, the sleeve having a first position in which the sleeve holds the first set of biased keys in a retracted position and a second position wherein the first set of keys are extended;   a second sleeve movable along the outer surface of the tool, the sleeve having a first position in which the sleeve holds the second set of biased keys in a retracted position and a second position wherein the second set of keys are extended;   whereby, the sleeves operate in a manner whereby when one of the two sets of keys is extended the other set is retracted.   
     
     
         10 . The tool of  claim 9 , wherein the first and second sleeves are disposed on a sleeve assembly and are movable along the surface of the tool together. 
     
     
         11 . The tool of  claim 10 , further including a downhole motor for translating the sleeve assembly along the surface of the tool to extend and retract the first and second sets of keys. 
     
     
         12 . The tool of  claim 11 , wherein the downhole motor includes a threaded shaft extending therefrom for engagement with a corresponding threaded member formed on the sleeve assembly for translating the sleeve. 
     
     
         13 . The tool of  claim 12 , wherein the first set of biased keys are constructed and arranged to open the port sleeve when the tool is moved axially in the wellbore and the second set of biased keys are constructed and arranged to close the port sleeve when the tool is moved. 
     
     
         14 . The tool of  claim 13 , wherein the first set of keys is disposed at an upper location on the tool and the second set is disposed at a lower location. 
     
     
         15 . The tool of  claim 14 , wherein the tool is lowered in the wellbore to open the port sleeve and raised in the wellbore to open the port sleeve. 
     
     
         16 . The tool of  claim 9 , wherein the profiles formed on the first and second sets of keys are a mirror image of each other. 
     
     
         17 . The tool of  claim 16 , wherein the mating profiles formed on the port sleeve are a mirror image of each other. 
     
     
         18 . A method of opening a port sleeve in a port sub, comprising:
 providing a port sub in a casing string, the sub having a port sleeve, the sleeve in a closed position;   providing a downhole tool at a position in the wellbore adjacent the port sleeve, the tool including:
 a first set of outwardly biased keys disposed at a first axial location along the tool, the first set including profiles formed thereon for engaging the a port sleeve, the port sleeve having mating profiles; 
 a second set of outwardly biased keys disposed at a second axial location along the tool, the second set having differently-shaped profiles formed thereon for engaging mating profiles on the port sleeve; and 
 a sleeve assembly disposed along an outer surface of the tool and movable between a first portion wherein the sleeve maintains the first set of keys in a retracted position and a second position wherein the sleeve maintains the second set of keys in a retracted position; 
 a downhole motor and threaded shaft, the shaft associated with the sleeve assembly for transmitting the sleeve between the first and second positions. engaging the port sleeve with the first set of keys; and 
   lowering the tool in the wellbore, thereby shifting the port sleeve from a closed to an open positon.   
     
     
         19 . The method of  claim 18 , further including:
 operating the motor and threaded shaft to translate the sleeve assembly, thereby retracting the first set of keys and extending the second set of keys;   engaging the port sleeve with the second set of keys; and   raising the tool in the wellbore, thereby shifting the port sleeve from the open to the closed position.