Alignment assembly for downhole tools and related methods

Abstract

An apparatus for perforating a subterranean formation comprises a first perforating gun (33b) having a box end (112) having a nose, a second perforating gun (33a) having a pin end (118) having a shoulder (124); and an alignment assembly. The alignment assembly includes internal threads formed on the box end, external threads formed on the pin end, and an alignment member (120) positioned between the box end nose and the pin end shoulder. The internal threads and the external threads are specified to form an angular alignment between the first perforating gun and the second perforating gun within a first specified angular tolerance. The alignment member has at least one characteristic selected to vary the angular alignment within the first specified angular tolerance without degrading a locking force connecting the first perforating gun to the second perforating gun.

1 . An apparatus for perforating a subterranean formation, comprising:
 a first perforating gun having a box end that includes a first slot;   a second perforating gun having a pin end that includes a second slot, wherein the first perforating gun and the second perforating gun are configured to have a specified angular alignment when fired;   a threaded connection that includes internal threads formed on the box end and external threads formed on the pin end, the threaded connection having a specified torque value range when the first perforating gun and the second perforating gun have the specified angular alignment, and   an alignment assembly having:
 an alignment member positioned between a first portion of the box end and the pin end, the alignment member configured to deform to maintain the specified torque value range when the box end and the pin end are rotated into the specified angular alignment, and 
 a locking member positioned between a second portion of the box end and the pin end, the locking member including a first tab and a second tab, the first tab being seated in the first slot and the second tab being seated in the second slot after the box end and the pin end are rotated into the specified angular alignment, locking member thereby physically connecting the box end and the pin end. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the locking member is positioned in a gap between a nose end of the box end and a shoulder of the pin end and the alignment member is positioned in a recess between a face of the pin end and an inner shoulder of the box end. 
     
     
         3 . The apparatus of  claim 1 , wherein the locking member has a body with a first face and an opposing second face, wherein the first tab projects from the first face and the second tab projects from the second face, and wherein the first tab and the second tab are configured to flex axially relative to one another. 
     
     
         4 . The apparatus of  claim 1 , wherein the body includes a slit at least partially physically separating the first tab from the second tab. 
     
     
         5 . The apparatus of  claim 1 , wherein the first perforating gun has at least one shaped charge and the second perforating gun has at least one shaped charge, and wherein the specified angular alignment is selected to cause perforating jets formed by the at least one shaped charge of the first perforating gun and the at least one shaped charge of the second perforating gun to travel in the same angular direction. 
     
     
         6 . An apparatus for perforating a subterranean formation, comprising:
 a first perforating gun having a box end;   a second perforating gun having a pin end, wherein the first perforating gun and the second perforating gun are configured to have a specified angular alignment;   a threaded connection that includes internal threads formed on the box end and external threads formed on the pin end, the threaded connection having a specified torque value range, and   an alignment assembly that includes a deformable alignment member positioned between a portion of the box end and the pin end, the alignment member configured to deform to maintain the specified torque value range when the box end and the pin end are rotated into the specified angular alignment.   
     
     
         7 . The apparatus of  claim 6 , wherein the alignment member is positioned in a gap between a nose end of the box end and a shoulder of the pin end. 
     
     
         8 . The apparatus of  claim 6 , wherein the alignment member is at least partially formed of a material having a modulus of elasticity within 20% of the modulus of elasticity of copper. 
     
     
         9 . The apparatus of  claim 6 , wherein the alignment member has a thickness selected to contact the pin end and the box end before the pin end and the box end can rotate into the specified angular alignment. 
     
     
         10 . The apparatus of  claim 6 , wherein the first perforating gun has at least one shaped charge and the second perforating gun has at least one shaped charge, and wherein the specified angular alignment is selected to cause perforating jets formed by the at least one shaped charge of the first perforating gun and the at least one shaped charge of the second perforating gun to travel in the same angular direction. 
     
     
         10 . A method for perforating a subterranean formation, comprising:
 configuring a perforating tool to include:
 a first perforating gun having a box end that includes a first slot; 
 a second perforating gun having a pin end that includes a second slot, wherein the first perforating gun and the second perforating gun are configured to have a specified angular alignment when fired; 
 a threaded connection that includes internal threads formed on the box end and external threads formed on the pin end, the threaded connection having a specified torque value range when the first perforating gun and the second perforating gun have the specified angular alignment, and 
 an alignment assembly having: 
 an alignment member positioned between a first portion of the box end and the pin end, the alignment member configured to deform to maintain the specified torque value range when the box end and the pin end are rotated into the specified angular alignment, and 
 a locking member positioned between a second portion of the box end and the pin end, the locking member including a first tab and a second tab, the first tab being seated in the first slot and the second tab being seated in the second slot after the box end and the pin end are rotated into the specified angular alignment, locking member thereby physically connecting the box end and the pin end; 
   conveying the perforating tool into a wellbore; and   firing the perforating tool.