Threaded tandem for wellbore operations

Abstract

An improved tandem for attachment to a perforating gun is provided. The tandem includes a cylindrical body having a first externally threaded end portion and a second externally threaded end portion. The first externally threaded end portion includes a first plurality of threads defining a first thread pattern, and the second externally threaded end portion includes a second plurality of threads defining a second thread pattern. The first thread pattern is different than the second thread pattern such that the cylindrical body is threadably attachable to first and second perforating guns in a single direction. The thread patterns can differ in at least one or more of the following: thread profile, thread pitch, pitch diameter, major diameter, minor diameter, and thread angle, by non-limiting example.

What is claimed is: 
     
         1 . A tandem for attachment to a perforating gun, the tandem comprising:
 a cylindrical body including a first externally threaded end portion and a second externally threaded portion, the cylindrical body further including a central cavity for receiving a pass-through element, the central cavity being disposed between a first narrowing opening and a second narrowing opening,   wherein the first externally threaded end portion includes a first plurality of threads defining a first thread pattern, and wherein the second externally threaded end portion includes a second plurality of threads defining a second thread pattern, the first thread pattern being different than the second thread pattern such that the cylindrical body is threadably attachable to first and second perforating guns in a single direction.   
     
     
         2 . The tandem of  claim 1 , wherein the first thread pattern includes a first major diameter and wherein the second thread pattern includes a second major diameter that is different from the first major diameter. 
     
     
         3 . The tandem of  claim 1 , wherein the first thread pattern includes a first minor diameter and wherein the second thread pattern includes a second minor diameter that is different from the first minor diameter. 
     
     
         4 . The tandem of  claim 1 , wherein the first thread pattern includes a first pitch diameter and wherein the second thread pattern includes a second pitch diameter that is different from the first pitch diameter. 
     
     
         5 . The tandem of  claim 1 , wherein the first thread pattern includes a first pitch and wherein the second thread pattern includes a second pitch that is different from the first pitch. 
     
     
         6 . The tandem of  claim 1 , wherein the first thread pattern includes a first thread angle and wherein the second thread pattern includes a second thread angle that is different from the first thread angle. 
     
     
         7 . The tandem of  claim 1 , wherein the first thread pattern includes a first thread profile and wherein the second thread pattern includes a second thread profile that is different from the first thread profile. 
     
     
         8 . The tandem of  claim 7 , wherein each of the first thread profile and the second thread profile are selected from the group consisting of an Acme thread profile, a V-shaped thread profile, a square thread profile, and a buttress thread profile. 
     
     
         9 . The tandem of  claim 1 , wherein at least two characteristics of the first thread pattern differ from at least two characteristics of the second thread pattern. 
     
     
         10 . The tandem of  claim 1 , wherein the first narrowing opening includes a first sloped sidewall and wherein the second narrowing opening includes a second sloped sidewall. 
     
     
         11 . A tandem for attachment to a perforating gun, the tandem comprising:
 a cylindrical body includes an exterior sidewall spaced apart from an interior sidewall, the interior sidewall defining a through-bore for receiving a pass-through element,   wherein the exterior sidewall includes a first externally threaded end portion and a second externally threaded portion, wherein the first externally threaded end portion includes a first plurality of threads defining a first thread pattern, and wherein the second externally threaded end portion includes a second plurality of threads defining a second thread pattern, the first thread pattern being different than the second thread pattern such that the cylindrical body is threadably attachable to first and second perforating guns in a single direction.   
     
     
         12 . The tandem of  claim 11 , wherein the first thread pattern includes a first major diameter and wherein the second thread pattern includes a second major diameter that is different from the first major diameter. 
     
     
         13 . The tandem of  claim 11 , wherein the first thread pattern includes a first minor diameter and wherein the second thread pattern includes a second minor diameter that is different from the first minor diameter. 
     
     
         14 . The tandem of  claim 11 , wherein the first thread pattern includes a first pitch diameter and wherein the second thread pattern includes a second pitch diameter that is different from the first pitch diameter. 
     
     
         15 . The tandem of  claim 11 , wherein the first thread pattern includes a first pitch and wherein the second thread pattern includes a second pitch that is different from the first pitch. 
     
     
         16 . The tandem of  claim 11 , wherein the first thread pattern includes a first thread angle and wherein the second thread pattern includes a second thread angle that is different from the first thread angle. 
     
     
         17 . The tandem of  claim 11 , wherein the first thread pattern includes a first thread profile and wherein the second thread pattern includes a second thread profile that is different from the first thread profile. 
     
     
         18 . The tandem of  claim 17 , wherein each of the first thread profile and the second thread profile are selected from the group consisting of an Acme thread profile, a V-shaped thread profile, a square thread profile, and a buttress thread profile. 
     
     
         19 . The tandem of  claim 11 , wherein at least two characteristics of the first thread pattern differ from at least two characteristics of the second thread pattern. 
     
     
         20 . The tandem of  claim 11 , wherein the through-bore includes a central cavity disposed between a first narrowing opening and a second narrowing opening.