High density perforating gun system producing reduced debris

Abstract

A perforating system has a perforating module comprising a unitary body of explosive. The explosive is contained within a non-explosive casing, or liner, having formed indentations and a cover thereover. The indentations, which will transform into explosively formed penetrators (EFP's) upon detonation, have a perimeter shape that allows for improved packing density, e.g., a hexagonal perimeter, which results in relatively little “dead space” wherein no perforating penetrators are generated. In operation, the module provides a relatively dense shot pattern and substantially reduced amount of post-detonation debris that could clog the perforations and/or require remedial clean-up or repeat perforation.

1 . An apparatus for perforating a subterranean formation comprising: 
 a perforation module conveyable into a wellbore drilled into the subterranean formation, the module including at least: 
 (a) a body of explosive material;  
 (b) a detonator for detonating the body of explosive material; and  
   (c) a liner surrounding at least a portion of the explosive material, the liner forming a plurality of perforating elements when the body of explosive material is detonated.    
   
   
       2 . The apparatus of  claim 2 , wherein the liner forms perforating elements that travel in a direction substantially perpendicular to a longitudinal axis of a wellbore.  
   
   
       3 . The apparatus of  claim 1 , wherein the liner circumferentially surrounds the body of explosive material.  
   
   
       4 . The apparatus of  claim 1 , wherein the detonator comprises a layer of primasheet.  
   
   
       5 . The apparatus of  claim 1  further comprising a support member within the body of explosive material that connects with a conveyance string.  
   
   
       6 . The apparatus of  claim 1 , wherein the liner is formed of tantalum.  
   
   
       7 . An apparatus for use in perforating a subterranean formation, comprising: 
 a perforation module comprising    a body of high explosive material; and    a liner surrounding the body of high explosive material, the liner presenting a radially outer surface having a plurality of indentations formed therein to be transformed into directional penetrators upon detonation of the body of high explosive material.    
   
   
       8 . The apparatus of  claim 7 , wherein the perforation module further comprises a substantially cylindrical cover member that radially surrounds the non-explosive liner to provide a standoff for the directional penetrators transformed from the indentations.  
   
   
       9 . The apparatus of  claim 7 , wherein the indentations have perimeters whose shape enables closer packing of the indentations than would be possible if the indentations had circular perimeters.  
   
   
       10 . The apparatus of  claim 9 , wherein each indentation has a perimeter that is one of: (i) triangular; (ii) square; (iii) pentagonal; (iv) hexagonal; and (v) octagonal.  
   
   
       11 . The apparatus of  claim 9 , wherein the indentations are arranged in a pattern over the outer radial surface such that each indentation is linearly contiguous with at least one other indentation.  
   
   
       12 . A method of perforating a subterranean formation comprising: 
 perforating a formation intersected by a wellbore with a plurality of penetrators formed from one liner.    
   
   
       13 . The method of  claim 12  further comprising detonating a body of high explosive in a wellbore to form the penetrators.  
   
   
       14 . The method of  claim 13  further comprising at least partially surrounding the body of high explosive with the one liner.  
   
   
       15 . The method of  claim 12  further comprising forming a plurality of indentations on the one liner.  
   
   
       16 . The method of  claim 12  further comprising directing the penetrators into the formation along a direction substantially normal to a longitudinal axis of the wellbore.  
   
   
       17 . The method of  claim 12  further comprising forming the penetrators to penetrate at least a casing positioned in the wellbore.