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 plurality of perforating modules in a wellbore, wherein each of the plurality of perforating modules comprises:
 a central rod having an exterior load bearing portion and a detonation layer formed of a first explosive exterior to the exterior load bearing portion; 
 a second explosive surrounding the central rod, wherein the second explosive is a unitary body; and 
 a liner surrounding the second explosive, wherein the liner has a plurality of horizontal rows of concave surface indentations, the second explosive explosively forming a plurality of shaped charges from the liner. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the liner circumferentially surrounds the second explosive. 
     
     
         3 . The apparatus of  claim 1 , wherein the detonation layer comprises a layer of primasheet. 
     
     
         4 . The apparatus of  claim 1  wherein the central rod connects with a conveyance string. 
     
     
         5 . The apparatus of  claim 1 , wherein the liner is formed of tantalum. 
     
     
         6 . The apparatus of  claim 1 , further comprising a substantially cylindrical cover member surrounds the liner. 
     
     
         7 . The apparatus of  claim 1 , wherein each indentation has a perimeter that is one of: (i) triangular; (ii) square; (iii) pentagonal; (iv) hexagonal; and (v) octagonal. 
     
     
         8 . The apparatus of  claim 1 , wherein the indentations are arranged in a pattern over outer radial surface of the liner such that each indentation is linearly contiguous with at least one other indentation. 
     
     
         9 . An apparatus for perforating a subterranean formation, comprising:
 a plurality of perforating modules in a wellbore, wherein each of the plurality of perforating modules comprises:
 a central rod having an exterior load bearing portion and a detonation layer formed of a first explosive exterior to the exterior load bearing portion; 
 a second explosive surrounding the central rod, wherein the second explosive is a unitary body; and 
   a liner surrounding the second explosive, wherein the liner has a plurality of horizontal rows of concave surface indentations, wherein the indentations are arranged in a pattern over an outer radial surface of the liner such that each indentation is linearly contiguous with at least one other indentation.