Tapered collet mechanism for shifting plug release

Abstract

Provided is an inner sleeve, a downhole tool, and a method for cementing. The inner sleeve, in at least one aspect, includes a tubular having an inside tubular surface and an outside tubular surface. The inner sleeve, according to this aspect, further includes a collet including two or more collet fingers coupled to one end of the tubular, the collet having an inside collet surface and an outside collet surface, and further wherein the inside collet surface flares outward from the inside tubular surface by an angle (θ0) when the collet is in its natural state.

1 . An inner sleeve, comprising:
 a tubular having an inside tubular surface and an outside tubular surface; and   a collet including two or more collet fingers coupled to one end of the tubular, the collet having an inside collet surface and an outside collet surface, and further wherein the inside collet surface flares outward from the inside tubular surface by an angle (θ 0 ) when the collet is in its natural state.   
     
     
         2 . The inner sleeve as recited in  claim 1 , wherein the angle (θ 0 ) is at least 1 degree. 
     
     
         3 . The inner sleeve as recited in  claim 1 , wherein the angle (θ 0 ) is at least 3 degrees. 
     
     
         4 . The inner sleeve as recited in  claim 1 , wherein the angle (θ 0 ) is at least 10 degrees. 
     
     
         5 . The inner sleeve as recited in  claim 1 , wherein the angle (θ 0 ) ranges from degrees to 15 degrees. 
     
     
         6 . The inner sleeve as recited in  claim 1 , further including two or more plug seats extending radially inward from the inside collet surface. 
     
     
         7 . The inner sleeve a recited in  claim 6 , wherein an inner most radial point of the two or more plug seats is radially outside of the inside tubular surface when the collet is in its natural state. 
     
     
         8 . A downhole tool, comprising:
 a valve connector housing; and   an inner sleeve located at least partially within the valve connector housing, the inner sleeve including:
 a tubular having an inside tubular surface and an outside tubular surface; and 
 a collet including two or more collet fingers coupled to one end of the tubular, the collet having an inside collet surface and an outside collet surface, and further wherein the collet is configured such that:
 when the collet is in its natural state outside of the valve connector housing the inside collet surface flares outward from the inside tubular surface by an angle (θ 0 ); and 
 when the collet is in its compressed state inside of the valve connector housing the inside tubular surface and the inside collet surface are angled with regard to each other by a lesser angle (θ 1 ). 
 
   
     
     
         9 . The downhole tool as recited in  claim 8 , further including:
 a body coupled to the valve connector housing and configured to fit within a casing string;   a first valve located within the body and configured to open and close a fluid flow path through the valve connector housing, wherein the first valve opens to a first valve open position in a direction towards a wellhead of the wellbore; and   a second valve located within the body and configured to open and close the fluid flow path through the valve connector housing, wherein the second valve opens to a second valve open position in a direction away from the wellhead of the wellbore.   
     
     
         10 . The downhole tool as recited in  claim 9 , wherein the first valve is configured to be in the first valve open position and the second valve is configured to be in a second valve closed position during placement of the downhole tool in the wellbore. 
     
     
         11 . The downhole tool as recited in  claim 9 , wherein the inner sleeve is configured to shift the collet from the compressed state to the natural state after placement of the downhole tool in the wellbore to move the first valve to a first valve closed position and the second valve to the second valve open position. 
     
     
         12 . The downhole tool as recited in  claim 8 , further including two or more plug seats extending radially inward from the inside collet surface. 
     
     
         13 . The downhole tool as recited in  claim 12 , wherein the collet is in the compressed state, and further wherein a plug engages with the two or more plug seats. 
     
     
         14 . The downhole tool as recited in  claim 13 , wherein an inner most radial point of the two or more plug seats is radially inside of the inside tubular surface. 
     
     
         15 . The downhole tool a recited in  claim 12 , wherein the collet is in the natural state, and further wherein an inner most radial point of the two or more plug seats is radially outside of the inside tubular surface. 
     
     
         16 . The downhole tool as recited in  claim 8 , wherein the angle (θ 0 ) is at least 1 degree. 
     
     
         17 . The downhole tool as recited in  claim 8 , wherein the angle (θ 0 ) is at least 3 degrees. 
     
     
         18 . The downhole tool as recited in  claim 8 , wherein the angle (θ 0 ) is at least degrees. 
     
     
         19 . The downhole tool as recited in  claim 8 , wherein the angle (θ 0 ) ranges from 5 degrees to 15 degrees. 
     
     
         20 . The downhole tool as recited in  claim 8 , wherein the lesser angle (θ 1 ) is 2 degrees or less. 
     
     
         21 . A method for cementing in a wellbore, comprising:
 obtaining a casing string and a downhole tool installed therein, wherein the downhole tool includes:
 a body coupled to the casing string; 
 a valve connector housing located within the body; 
 an inner sleeve located at least partially within the valve connector housing, the inner sleeve including:
 a tubular having an inside tubular surface and an outside tubular surface; and 
 a collet including two or more collet fingers coupled to one end of the tubular, the collet having an inside collet surface and an outside collet surface, and further wherein the collet is in its compressed state inside of the valve connector housing, the inside tubular surface and the inside collet surface angled with regard to each other by a lesser angle (θ 1 ); 
 
 a first valve located within the body and configured to open and close a fluid flow path through the valve connector housing, wherein the first valve is in a first valve open position; and 
 a second valve located within the body and configured to open and close the fluid flow path through the valve connector housing, wherein the second valve is in a second valve closed position; and 
   introducing the casing string and the downhole tool into a wellbore.   
     
     
         22 . The method as recited in  claim 21 , further including introducing cement composition into an annulus located between a wall of the wellbore and an outside of the casing string after introducing the casing string and the downhole tool into the wellbore. 
     
     
         23 . The method as recited in  claim 22 , wherein two or more plug seats extend radially inward from the inside collet surface, and further including introducing a plug into the casing string and the inner sleeve, wherein the plug engages with the two or more plug seats to create a seal and a pressure differential, and wherein the pressure differential causes the inner sleeve to shift from the compressed state to the natural state. 
     
     
         24 . The method as recited in  claim 23 , wherein the shift from the compressed state to the natural state moves the first valve to a first valve closed position and the second valve to a second valve open position. 
     
     
         25 . The method as recited in  claim 23 , wherein the shift from the compressed state to the natural state allows the inside collet surface to flare outward from the inside tubular surface by an angle (θ 0 ) allowing the plug to disengage from the two or more plug seats and leave the downhole tool. 
     
     
         26 . The method as recited in  claim 23 , wherein the angle (θ 0 ) is at least 1 degree. 
     
     
         27 . The method as recited in  claim 23 , wherein the angle (θ 0 ) is at least 3 degrees. 
     
     
         28 . The method as recited in  claim 23 , wherein the angle (θ 0 ) is at least 10 degrees. 
     
     
         29 . The method as recited in  claim 23 , wherein the angle (θ 0 ) ranges from degrees to 15 degrees. 
     
     
         30 . The method as recited in  claim 21 , wherein the angle (θ 1 ) is 2 degrees or less.