Asymmetric initiated shaped charge and method for making a slot-like perforation

Abstract

A shaped charge is configured to make a non-circular perforation into a casing. The shaped charge includes a case having a side wall that extends between an open top region and a base; an asymmetric initiation insert configured to fit within the case; an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and a liner placed over the explosive material, to hold the explosive material within the case. The asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels.

What is claimed is: 
     
         1 . A shaped charge for making a non-circular perforation into a casing, the shaped charge comprising:
 a case having a side wall that extends between an open top region and a base;   an asymmetric initiation insert configured to fit within the case;   an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and   a liner placed over the explosive material, to hold the explosive material within the case,   wherein the asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels.   
     
     
         2 . The shaped charge of  claim 1 , wherein the top surface of the body is convex. 
     
     
         3 . The shaped charge of  claim 1 , wherein the top surface of the body is part of a sphere of a given radius R. 
     
     
         4 . The shaped charge of  claim 1 , wherein the asymmetric initiation insert fits tightly over the base and side wall of the case so that no explosive material is present at an interface between the asymmetric initiation insert and the case. 
     
     
         5 . The shaped charge of  claim 1 , further comprising:
 a booster material placed in a conduit formed in the base of the case,   wherein the conduit is configured to drive a flame from the booster material to the first and second channels of the asymmetric initiation insert.   
     
     
         6 . The shaped charge of  claim 1 , further comprising:
 a booster material placed in a conduit formed in the base of the case,   wherein the booster material is in direct contact with the first and second channels.   
     
     
         7 . The shaped charge of  claim 1 , wherein each of the first and second channels is fully formed within the body of the asymmetric initiation insert. 
     
     
         8 . The shaped charge of  claim 1 , wherein each of the first and second channels is partially open to a side of the asymmetric initiation insert. 
     
     
         9 . The shaped charge of  claim 1 , wherein the first and second channels are cylinders having a constant radius. 
     
     
         10 . The shaped charge of  claim 1 , wherein the first and second channels are conical frustums. 
     
     
         11 . A perforating gun for perforating a casing in a well, the perforating gun comprising:
 a casing; and   a shaped charge provided within the casing and configured to make a non-circular perforation into the casing,   wherein the shaped charge includes an asymmetric initiation insert having a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels, and   wherein the first and second initiation points make the shaped charge to form a non-circular perforation into the casing.   
     
     
         12 . The perforating gun of  claim 11 , wherein the shaped charge comprises:
 a case having a side wall that extends between an open top region and a base;   the asymmetric initiation insert is configured to fit within the case;   an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and   a liner placed over the explosive material, to hold the explosive material within the case.   
     
     
         13 . The perforating gun of  claim 12 , wherein the top surface of the body is convex. 
     
     
         14 . The perforating gun of  claim 12 , wherein the top surface of the body is part of a sphere of a given radius R. 
     
     
         15 . The perforating gun of  claim 12 , wherein the asymmetric initiation insert fits tightly over the base and side wall of the case so that no explosive material is present at an interface between the asymmetric initiation insert and the case. 
     
     
         16 . The perforating gun of  claim 12 , wherein the shaped charge further comprises:
 a booster material placed in a conduit formed in the base of the case,   wherein the conduit is configured to drive a flame from the booster material to the first and second channels of the asymmetric initiation insert.   
     
     
         17 . The perforating gun of  claim 12 , wherein each of the first and second channels is fully formed within the body of the asymmetric initiation insert. 
     
     
         18 . The perforating gun of  claim 12 , wherein the first and second channels of the asymmetric initiation insert are cylinders having a constant radius. 
     
     
         19 . The perforating gun of  claim 12 , wherein the first and second channels of the asymmetric initiation insert are conical frustums. 
     
     
         20 . A method of manufacturing a shaped charge that generates a non-circular perforation in a casing, the method comprising:
 providing a case for the shaped charge;   placing an asymmetric initiation insert within the case;   orienting angularly the asymmetric initiation insert relative to the case to achieve a desired orientation of the non-circular perforation relative to the casing;   placing an explosive material over the asymmetric initiation insert and in contact with a side wall of the case; and   placing a liner over the explosive material, to hold the explosive material within the case,   wherein the asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points at the top surface, which correspond to the first and second channels.