Casing transition nipple and method of casing a well to facilitate well completion, re-completion and workover

Abstract

A casing transition nipple and method of casing a well facilitates well completion, re-completion and workover while increasing safety and reducing expense. The casing transition nipple provides a connection between a large diameter production casing joint suspended by a wellhead and a standard production casing string. The large diameter production casing joint permits long downhole tool strings to be lubricated into the well without leaving a high lubricator profile and reduces the cost of performing many other well completion, re-completion and workover procedures.

1 . A casing transition nipple, comprising: 
 a tubular body having a top end adapted for fluid tight connection to a well casing of a fist diameter and a bottom end adapted for fluid tight connection to a well casing of a second, smaller diameter; and    a smooth annular tool guide surface between the first and second ends.    
   
   
       2 . The casing transition nipple as claimed in  claim 1  wherein the fluid tight connections to the top and bottom ends comprise one or more of: threaded, welded, locking or glued connections.  
   
   
       3 . The casing transition nipple as claimed in  claim 2  wherein the wherein the top end is box threaded and the bottom end is box threaded.  
   
   
       4 . The casing transition nipple as claimed in  claim 2  wherein where in the top end is box threaded and the bottom end is pin threaded.  
   
   
       5 . The casing transition nipple as claimed in  claim 2  wherein the top end is pin threaded and the bottom end is box threaded.  
   
   
       6 . The casing transition nipple as clamed in  claim 2  wherein the top end is pin threaded and the bottom end is pin threaded.  
   
   
       7 . The casing transition nipple as claimed in  claim 1  wherein the annular tool guide surface slopes downwardly at an angle of a 30°-60° with respect to a plain that is perpendicular to the top and bottom ends.  
   
   
       8 . A method of casing a wellbore, comprising: 
 running a production casing of a first diameter into the wellbore until a bottom end of the production casing of the first diameter is approximately a predetermined distance from a bottom of the wellbore;    connecting a bottom end of a casing transition nipple to a top end of the casing of the first diameter;    connecting a bottom end of a production casing of a second, larger diameter to a top end of the casing transition nipple, the production casing of the second diameter having a length approximately equal to the predetermined distance; and    suspending the production casing of the second, larger diameter from a wellhead of the well.    
   
   
       9 . The method as claimed in  claim 8  wherein suspending the production casing of the second, larger diameter from the wellhead comprises suspending the production casing using a casing mandrel.  
   
   
       10 . The method as claimed in  claim 8  wherein suspending the production casing of the second, larger diameter from the wellhead comprises suspending the production casing using casing slips.  
   
   
       11 . The method as claimed in  claim 8  wherein the predetermined distance is 6-60 feet.  
   
   
       12 . The method as claimed in  claim 8  wherein the diameter of the first casing is one of 4½, 5 and 5½ inches.  
   
   
       13 . The method as claimed in  claim 10  wherein a diameter of the second casing is 5½-8 inches.  
   
   
       14 . The method as claimed in  claim 8  further comprising using at least one casing collar to connect at least one of the casings of the first and second diameter to the casing transition nipple.  
   
   
       15 . A method of casing a wellbore of a predetermined depth, comprising: 
 running a production casing of a first diameter into the wellbore until a bottom end of the production casing of the first diameter is at a depth that is less than the predetermined depth of the wellbore;    connecting a bottom end of a casing transition nipple to a top end of the production casing of the first diameter;    connecting a bottom end of a production casing of a second, larger diameter to a top end of the casing transition nipple; and    running the production casing of the second, larger diameter into the wellbore until the wellbore is cased.    
   
   
       16 . The method as claimed in  claim 15  further comprising suspending the production casing of the second, larger diameter from a wellhead that suspends a surface casing in the wellbore.  
   
   
       17 . The method as claimed in  claim 16  wherein suspending the production casing comprises connecting a top end of the production casing to a casing mandrel and landing the casing mandrel in a casing bowl of the wellhead.  
   
   
       18 . The method as claimed in  claim 16  wherein suspending the production casing comprises landing casing slips around the production casing in a casing bowl of the wellhead, and cutting off a top of the production casing above the casing slips.  
   
   
       19 . The method as claimed in  claim 15  wherein a difference between the depth of the wellbore and the depth to which the production casing of the first diameter is run into the wellbore is about 6-60 feet.  
   
   
       20 . The method as claimed in  claim 15  wherein a difference in a diameter of the production casing of the first diameter and the production casing of the second diameter is about 1½″-3½″.