Perforating gun and arming method

Abstract

The perforating gun and methods of arming a perforating gun facilitates electrically connecting an arming device carrying the detonator to the loading tube carrying the explosive charges prior to ballistically connecting the arming device to the loading tube. Subsequent to establishing electrical continuity across the loading tube and arming device, the arming device can be ballistically connected to the loading tube thereby arming the perforating gun.

1 . A perforating gun apparatus, comprising:
 a loading tube comprising an explosive charge, an electrical conductor, and a detonating cord; and   an arming device comprising a detonator and an electrical connector, the arming device moveable between a park position and an armed position, in the park position the arming device is electrically connected to the loading tube and the arming device is not ballistically connected to the loading tube, and in the armed position the arming device is electrically and ballistically connected to the loading tube.   
     
     
         2 . The apparatus of  claim 1 , wherein the detonator is angularly offset from the detonating cord when the arming device is in the park position. 
     
     
         3 . The apparatus of  claim 1 , wherein in the park position the detonator is angularly offset from an end of the detonating cord and in the armed position the detonator is aligned with the end of the detonating cord. 
     
     
         4 . The apparatus of  claim 1 , further comprising a lock device permitting rotational movement of the arming device relative to the loading tube between the park position and the armed position and the locking device blocking axial movement of the arming device relative to the loading tube when the arming device is in the armed position. 
     
     
         5 . The apparatus of  claim 4 , wherein in the park position the detonator is angularly offset from an end of the detonating cord and in the armed position the detonator is aligned with the end of the detonating cord. 
     
     
         6 . The apparatus of  claim 4 , wherein the lock device comprises:
 a protrusion comprising a head extending away from a face of one of the arming device and the loading tube; and   a groove cooperative to receive the protrusion disposed with the other of the arming device and the loading tube.   
     
     
         7 . The apparatus of  claim 6 , wherein the groove comprises:
 a first leg extending axially from a face of the other of the arming device and the loading tube, and   a second leg extending angularly away from the first leg to a stop.   
     
     
         8 . The apparatus of  claim 7 , wherein the head of the protrusion is positioned in the second leg of the groove proximate to the stop when the arming device is in the armed position. 
     
     
         9 . The apparatus of  claim 1 , further comprising a locking device comprising:
 a protrusion comprising a head extending away from a face of one of the arming device and the loading tube by a post, wherein the head has a cross-sectional diameter greater than that of the post; and   a groove formed by the other of the arming device and the loading tube comprising a first leg extending axially away from a face of the other of the arming device and the loading tube and a second leg extending angularly from the first leg to a stop, wherein the head of the protrusion is positioned in the second leg of the groove proximate to the stop when the arming device is in the armed position.   
     
     
         10 . The apparatus of  claim 9 , wherein in the park position the detonator is angularly offset from an end of the detonating cord and in the armed position the detonator is aligned with the end of the detonating cord 
     
     
         11 . The apparatus of  claim 9 , wherein the protrusion is disposed from the arming device and the groove is formed by the loading tube. 
     
     
         12 . A method of arming a perforating gun, comprising:
 electrically connecting an arming device to a loading tube; and   ballistically connecting the arming device to the loading tube after the electrically connecting the arming device to the loading tube.   
     
     
         13 . The method of  claim 12 , wherein the ballistically connecting the arming device to the loading tube comprises aligning a detonator of the arming device with an end of a detonating cord of the loading tube. 
     
     
         14 . The method of  claim 12 , wherein the ballistically connecting the arming device to the loading tube comprises aligning a detonator of the arming device with an end of a detonating cord of the loading tube in response to rotating the arming device relative to the loading tube. 
     
     
         15 . The method of  claim 12 , wherein:
 the electrically connecting the arming device to the loading tube comprises moving the arming device axially to the loading tube to a park position connecting an electrical connector of the arming device to an electrical connector of the loading tube; and   the ballistically connecting the arming device to the loading tube comprises aligning a detonator of the arming device with an end of a detonating cord of the loading tube in response to rotating the arming device relative to the loading tube from the park position to an armed position.   
     
     
         16 . The method of  claim 12 , further comprising blocking, when the arming device is in the armed position, axial movement of the arming device relative to the loading tube. 
     
     
         17 . A method for arming a perforating gun, comprising:
 positioning an arming device comprising an electrical connector and a detonator proximate an end of a loading tube disposed within a carrier, the loading tube comprising an explosive charge, an electrical conductor having an electrical connector located proximate the end of the loading tube, and a detonating cord connected to the explosive charge and having an end located proximate to the end of the loading tube;   electrically connecting the arming device to the loading tube in response to moving the arming device to a park position; and   ballistically connecting the arming device to the loading tube after electrically connecting the arming device to the loading tube in response to moving the arming device from the park position to an armed position.   
     
     
         18 . The method of  claim 17 , wherein:
 the moving the arming device to a park position comprises axially moving the arming device to the loading tube connecting the electric connector of the arming device to the electric connector of the loading tube; and   the moving the arming device from the park position to the armed position comprises rotating the arming device relative to the loading tube.   
     
     
         19 . The method of  claim 18 , wherein the perforating gun further comprises a locking device comprising:
 a protrusion comprising a head extending away from a face of one of the arming device and the loading tube by a post, wherein the head has a cross-sectional diameter greater than that of the post; and   a groove formed by the other of the arming device and the loading tube comprising a first leg extending axially away from a face of the other of the arming device and the loading tube and a second leg extending angularly from the first leg to a stop, wherein the head of the protrusion is positioned in the second leg of the groove proximate to the stop when the arming device is in the armed position.   
     
     
         20 . The method of  claim 18 , further comprising blocking, when the arming device is in the armed position, axial movement of the arming device relative to the loading tube. 
     
     
         21 . The method of  claim 18 , wherein the carrier does not include ports in the side thereof for electrically connecting the arming device to the loading tube or ballistically connecting the arming device to the loading tube. 
     
     
         22 . A method of assembling a perforating gun, comprising:
 inserting a first loading tube assembly into a first tubular carrier member;   indexing the first loading tube assembly to a first desired orientation relative to the first tubular carrier member;   securing the first loading tube assembly to the first tubular carrier member to resist indexing of the first loading tube assembly from the first desired orientation;   securing a second tubular carrier member to the first tubular carrier member;   inserting a second loading tube assembly into the second tubular carrier member;   indexing the second loading tube assembly to a desired orientation relative to the second tubular carrier member; and   securing the second loading tube assembly to the second tubular carrier member to resist indexing of the second loading tube assembly from the second desired orientation.   
     
     
         23 . The method of  claim 23 , wherein the second desired orientation is the same as the desired orientation. 
     
     
         24 . The method of  claim 23  wherein securing the second tubular carrier member to the first tubular carrier member includes securing the second tubular carrier member directly to the first tubular carrier member. 
     
     
         25 . The method of  claim 23  wherein securing the second tubular carrier member to the first tubular carrier member includes rotating the second tubular carrier member directly to the first tubular carrier member to threadingly connect the first and second tubular carrier members. 
     
     
         26 . The method of  claim 24 , wherein securing the second tubular carrier member to the first tubular carrier member further includes inserting a securing member into an opening of one of the first and second carrier members to engage the other of the first and second carrier members to resist rotation of the one carrier member relative to the other carrier member. 
     
     
         27 . The method of  claim 23 , wherein the first loading tube can be indexed to unlimited positions relative to the first tubular carrier member.