Perforating gun assembly

Abstract

A perforating gun assembly includes a gun carrier and a gun connected thereto. The perforating gun is positioned external to a flow passage of the perforating gun carrier. The perforating gun is activated by pressure in the flow passage defined by the perforating gun carrier. The perforating gun may be positioned in a slot or pocket defined in a wall of the perforating gun carrier.

What is claimed is: 
     
         1 . A gun assembly for perforating a well comprising:
 a gun carrier having a circular outer periphery, and defining a central flow passage therethrough; and   a perforating gun positioned in a pocket defined in a wall of the gun carrier.   
     
     
         2 . The gun assembly of  claim 1  comprising the wall of the gun carrier defining two gun pockets for carrying perforating guns, the gun assembly comprising a perforating gun in each of the gun pockets. 
     
     
         3 . The gun assembly of  claim 2  wherein the two perforating guns are positioned in parallel spaced relationship. 
     
     
         4 . The gun assembly of  claim 2  further comprising a casing string for lowering the gun assembly into the well, the gun assembly having a longitudinal central axis that is colinear with a longitudinal central axis of the casing string. 
     
     
         5 . The gun assembly of  claim 1 , wherein the gun assembly is adapted to be lowered into a well and centrally located in the well. 
     
     
         6 . The gun assembly of  claim 1  wherein the perforating gun is activated by the application of fluid pressure in the carrier flow passage. 
     
     
         7 . The gun assembly of  claim 6  further comprising a hydraulic delay assembly for delaying the activation of the gun after pressure in the carrier flow passage has reached the activation pressure. 
     
     
         8 . The gun assembly of  claim 7 , the hydraulic delay assembly comprising:
 an upper chamber; +   a lower chamber;   a removable barrier positioned between the upper and lower chambers; and   a piston positioned in the upper chamber, an upper chamber wall having a passage defined therein for communicating fluid from the carrier flow passage into the upper chamber.   
     
     
         9 . The gun assembly of  claim 6 , a gun carrier wall having a port defined therein for communicating fluid therethrough into a chamber positioned outside the gun carrier wall, further comprising a removable barrier located to prevent flow through the port until a predetermined pressure in the carrier flow passage is reached, and wherein the continued application of pressure after the removable barrier is removed will activate the perforating gun. 
     
     
         10 . A downhole tool comprising:
 a tubular joint defining a flow passage therethrough; and   a perforating gun mounted to the joint and positioned external to the carrier flow passage in the tubular joint, wherein the application of fluid pressure in the flow passage will activate the perforating gun.   
     
     
         11 . The downhole tool of  claim 10 , the flow passage in the tubular joint comprising an eccentric flow passage, and wherein the perforating gun is positioned in a slot defined in a wall of the tubular joint. 
     
     
         12 . The downhole tool of  claim 11 , wherein two perforating guns are positioned in the slot. 
     
     
         13 . The downhole tools of  claim 12 , wherein the guns are positioned side by side in the slot. 
     
     
         14 . The downhole tool of  claim 11  further comprising a casing string, the tubular joint being connected in the casing string, wherein the tubular joint is concentric with the casing string. 
     
     
         15 . The downhole tool of  claim 11  further comprising a detonation housing disposed external to the flow passage in the tubular joint, the detonation housing defining a detonation chamber, the wall of the tubular joint having a port therethrough to communicate fluid from the eccentric flow passage to the detonation chamber, wherein the perforating gun is detonated as a result of fluid communicated into the detonation chamber from the eccentric flow passage. 
     
     
         16 . The downhole tool of  claim 15 , the detonation chamber comprising:
 an upper chamber;   a lower chamber; and   a removable barrier positioned between the upper and lower chambers, the barrier being rupturable upon the application of fluid pressure resulting from fluid flow into the detonation chamber from the eccentric flow passage.   
     
     
         17 . The tool of  claim 16  further comprising a nozzle positioned between the upper and lower chambers. 
     
     
         18 . The tool of  claim 16 , further comprising a piston in the upper chamber, wherein fluid flow from the flow passage urges the piston towards the lower chamber, the upper chamber being filled with fluid below the piston. 
     
     
         19 . A tool for perforating a well comprising:
 a casing string positioned in the well, ; and   a gun assembly connected in the casing string, the gun assembly comprising:
 a carrier defining a carrier flow passage therethrough; and 
 a gun positioned in a slot defined in the carrier wall external to the flow passage, wherein the gun assembly is concentric with the casing joint. 
   
     
     
         20 . The tool of  claim 19 , wherein the carrier flow passage is an eccentric flow passage. 
     
     
         21 . The tool of  claim 19 , wherein the gun is a pressure activated gun, and wherein the gun is activated by fluid pressure applied in the carrier flow passage. 
     
     
         22 . The tool of  claim 21 , further comprising:
 a detonation housing connected to the gun, the detonation housing defining a detonation chamber;   a wall of the carrier defining a flow port communicating the carrier flow passage with the detonation chamber; and   a removable barrier positioned to block communication through the flow port, wherein the barrier is removable upon application of a predetermined pressure to allow communication therethrough and wherein the gun will detonate upon the application of pressure in the carrier flow passage.   
     
     
         23 . The tool of  claim 19  wherein the carrier defines a pair of gun slots for receiving perforating guns, further comprising a perforating gun positioned in each slot. 
     
     
         24 . The tool of  claim 23 , the pair of guns having parallel, spaced longitudinal central axes. 
     
     
         25 . The tool of  claim 24 , wherein the detonation housing is positioned in a slot located above the gun slots.