Pressure balanced percussion firing system

Claim 2

Percussion firing apparatus for firing an explosive charge means within a well penetrating subterranean formations comprising: a. pressure balancing means for neutralizing adverse effects of external pressure and of internal pressure and changes therein; said pressure balancing means including a pressure balancing chamber and a pressure balancing piston that sealingly excludes fluid communication between a firing pin chamber and the exterior of said percussion firing apparatus; b. a firing pin chamber having therein a firing pin assembly that includes: i. a firing pin disposed within said firing pin assembly; and ii. arming means disposed intermediate said firing pin and said pressure balancing chamber and piston such that said firing pin can be forced sharply downwardly by a downward force on said pressure balancing piston; said arming means being normally unarmed until after said percussion firing apparatus is set in a conduit in said well; c. igniter means disposed beneath said firing pin so as to be ignited responsive to a downwardly moved firing pin; d. settable hanging means for suspending said percussion firing apparatus in a conduit within said well; said hanging means being set by a downward force and released by an upward force; and e. first connection means for connection with a device that is actuated responsive to the firing of said igniter means.

Claim 3

The percussion firing apparatus of claim 1 wherein said arming means includes a hammer pin assembly that is Disposed intermediate said firing pin and said pressure balancing piston so as to be engaged by said pressure balancing piston when it is moved downwardly for ignition of said igniter means.

Claim 4

The percussion firing apparatus of claim 2 wherein a releasable piston retainer means is provided; said releasable piston retainer means holding said pressure balancing piston at a predetermined position longitudinally of said pressure balancing chamber and releasing said pressure balancing piston for downward movement when subjected to sufficient downward force.

Claim 5

The percussion firing apparatus of claim 2 wherein there is provided a single-fire safety means interposed intermediate said firing pin and said pressure balancing piston; said single-fire safety means allowing arming said hammer pin assembly such that said downward force on said pressure balancing piston will cause said firing pin to attempt ignition of said igniter means; said single-fire safety means also effecting disarming of said hammer pin assembly after one said attempt.

Claim 6

The percussion firing apparatus of claim 4 wherein said single-fire safety means comprises a hammer pin; a hammer pin skirt defining a path directing said hammer pin to said firing pin; said hammer pin being slidably disposed within said hammer pin skirt; and a releasable hammer pin retainer means retaining said hammer pin at the upper portion of said hammer pin skirt prior to attempting ignition of said igniter means by striking said firing pin with said hammer pin; said releasable hammer pin retainer means releasing said hammer pin for striking said firing pin when subjected to sufficient downward force.

Claim 7

The percussion firing apparatus of claim 5 wherein said releasable hammer pin retainer means comprises a shear pin extending laterally through said hammer pin skirt and at least into said hammer pin; and said hammer pin skirt has a top portion that closely and conformingly fits the exterior of the bottom of the hammer pin and has an enlarged bore immediately therebelow for preventing any dragging and fluid compression effects and allowing free and rapid downward movement of the hammer pin once the shear pin has been sheared.

Claim 8

The percussion firing apparatus of claim 5 wherein said arming means includes a releasable piston retainer means for retaining said pressure balancing piston in place with respect to said hammer pin prior to moving downwardly for effecting firing; and includes a biasing means intermediate said hammer pin said said pressure balancing piston for storing a predetermined amount of energy for accelerating said hammer pin once said respective releasable piston and hammer pin retainer means have been released to ensure that said firing pin is struck sufficiently hard to effect ignition of said igniter means.

Claim 9

The percussion firing apparatus of claim 7 wherein said single-fire safety means includes a shoulder on said hammer pin skirt and a stop ring at the lower end of said biasing means for preventing downward movement of the lower end of said biasing means beyond said hammer pin skirt whereby downward force on said hammer pin and said firing pin cannot be exerted by said biasing means after said single attempt at firing.

Claim 10

The percussion firing apparatus of claim 8 wherein said biasing means comprises a spring; and said hammer pin and said shoulder are so designed that said stop ring encounters said shoulder before said hammer pin encounters said firing pin whereby said hammer pin is accelerated by said spring, said spring is prevented from acting upon said hammer pin all the way to said firing pin, and said hammer pin relies upon inertial force to strike said firing pin with the correct force.

Claim 11

The percussion firing apparatus of claim 8 wherein said single-fire safety also includes an exteriorly protruding shoulder on said pressure balancing piston and an interiorly protruding shoulder for limiting downward motion of said pressure balancing piston to prevent its imposing a force on saiD firing pin by way of said hammer pin after said releasable hammer pin retainer means has been released for firing.

Claim 12

The percussion firing apparatus of claim 1 wherein said pressure balancing piston has an upwardly protruding member that is adapted to be acted on for moving said pressure balancing piston downwardly for effecting arming and firing.

Claim 13

The percussion firing apparatus of claim 11 wherein a fishing neck means is disposed at the upper end of said percussion firing apparatus and is adapted for being suspended from a ''''shear down'''' wire line running tool and adapted for being engaged and pulled upwardly by a ''''shear up'''' pulling tool.

Claim 14

The percussion firing apparatus of claim 12 wherein said fishing neck means includes an internal fish neck; a housing defines a prong-receiving chamber surrounding said upwardly protruding member on said pressure balancing piston; and apertures are provided in said housing, said apertures having downwardly and outwardly inclined surfaces for draining off trash, debris and the like.

Claim 15

The percussion firing apparatus of claim 13 wherein a simple one-piece prong is included, said prong having a connection means at its upper end for connection with a pulling tool and being adapted to fit inside said fishing neck means and having its lower end adapted to contact said upwardly protruding member of said pressure balancing piston for forcing it downwardly.

Claim 16

The percussion firing apparatus of claim 13 wherein said prong and said prong-receiving chamber and proportioned such that said pulling tool will have engaged said fishing neck means before said firing pin fires said igniter means responsive to downward pressure of said prong.

Claim 17

The percussion firing apparatus of claim 12 wherein said fishing neck means includes an external fish neck and said upwardly protruding member on said pressure balancing piston extends above said external fish neck in the run-in, unarmed position before the arming and firing attempt is made.

Claim 18

The percussion firing apparatus of claim 1 wherein said firing pin has a controlled penetrating depth feature that assures adequate penetration for ignition but acts as a safety feature in instances where ignition fails to occur.

Claim 19

The percussion firing apparatus of claim 17 wherein said controlled penetrating depth feature includes an enlarged head on said firing pin, said enlarged head having a relatively large flat bottom surface for encountering a second flat surface to limit downward movement thereof; and said firing pin is disposed in an aperture that is surrounded at its upper end by a second, relatively large, flat surface for stopping downward movement of said enlarged head and said firing pin.

Claim 20

The percussion firing apparatus of claim 1 wherein said pressure balancing piston is disposed in said pressure balancing chamber; first and second bores communicate with respective ends of said pressure balancing chamber, said first bore communicating with the exterior of said percussion firing apparatus and said second bore communicating interiorly thereof with said firing pin chamber; said pressure balancing piston having an upwardly extending member disposed in said first bore and having a first cross sectional area that is exposed to pressure exteriorly of said percussion firing apparatus; said pressure balancing piston having a large central portion having a second cross sectional area; an aperture communicating with said pressure balancing chamber near its end closest to said second bore and communicating exteriorly of said percussion firing apparatus for exposing the lower portion of said pressure balancing chamber to pressure exteriorly of said percussion firing apparatus; said pressure balancing piston having a lower end disposed in said second bore such that said pressure balancing piston is slidable longitudinally of said first and second bores and said pressure balancing chamber; said pressure balancing piston having a longitudinally extending internal Passageway communicating intermediate said second bore and an upper portion of said pressure balancing chamber intermediate said enlarged portion of said pressure balancing piston and said first bore for exposing the upper portion of said pressure balancing chamber to pressure interiorly of said percussion firing apparatus; said lower end of said pressure balancing piston having a third cross sectional area; said second cross sectional area being enough larger than said first and third cross sectional areas that pressure interiorly of said percussion firing apparatus will act on exposed said third area and the top exterior portion of said second area and the pressure exteriorly of said percussion firing apparatus will act on said first area and the bottom exterior portion of said second area to create equal and opposing forces that neutralize each other such that said pressure balancing piston is moved responsive to a force other than pressure and the effects of pressure are neutralized.

Claim 21

The percussion firing apparatus of claim 1 wherein an elongate detonation passageway is disposed intermediate said igniter means and said first connection means for downward passage of the shock wave from the ignited igniter means; and wherein a shooting adapter and a booster pellet are connected with said first connection means and have a third connection means similar to said first connection means for connecting with a device that is actuated responsive to firing of said booster pellet.

Claim 22

Percussion firing apparatus for firing an explosive charge means within a well penetrating subterranean formations, having means for suspending a percussion firing head assembly at a predetermined depth, comprising: a. pressure balancing means for neutralizing adverse effects of external pressure and of internal pressure and changes therein; said pressure balancing means including a pressure balancing chamber and a pressure balancing piston that sealingly excludes fluid communication between a firing pin chamber and the exterior of said percussion firing apparatus; b. a firing pin chamber having therein a firing pin assembly that includes: i. a firing pin disposed within said firing pin assembly; and ii. arming means disposed intermediate said firing pin and said pressure balancing chamber and piston such that said firing pin can be forced sharply downwardly by a downward force on said pressure balancing piston; said arming means being normally unarmed until after said percussion firing apparatus is set in a conduit in said well; c. igniter means disposed beneath said firing pin so as to be ignited responsive to a downwardly moved firing pin; and d. first connection means for connection with a device that is actuated responsive to the firing of said igniter means.

Claim 23

Percussion firing apparatus for firing an explosive charge means within a well penetrating subterranean formations, having means for suspending a percussion firing head assembly at a predetermined depth, comprising: a. pressure balancing means for neutralizing adverse effects of external pressure and of internal pressure and changes therein; said pressure balancing means including a pressure balancing chamber and a pressure balancing piston that sealingly excludes fluid communication between a firing pin chamber and the exterior of said percussion firing apparatus; b. a firing pin chamber having therein a firing pin assembly that includes: i. a firing pin disposed within said firing pin assembly; and ii. arming means disposed intermediate said firing pin and said pressure balancing chamber and piston such that said firing pin can be forced sharply downwardly by a downward force on said pressure balancing piston; said arming means being normally unarmed until after said percussion firing apparatus is set in a conduit in said well; c. igniter means disposed beneath said firing pin so as to be ignited responsive to a downwardly moved firing pin; and d. first connection means for connection with a device that is actuated responsive to the firing of said igniter means.

Claim 24

The percussion firing apparatus of claim 21 wherein said arming means includes a hammer pin assembly that is disposed intermediate said firing pin and said pressure balancing piston so as to be engaged by said pressure balancing piston when it is moved downwardly for ignition of said igniter means.

Claim 25

The percussion firing apparatus of claim 22 wherein a releasable piston retainer means is provided; said releasable piston retainer means holding said pressure balancing piston at a predetermined position longitudinally of said pressure balancing chamber and releasing said pressure balancing piston for downward movement when subjected to sufficient downward force.

Claim 26

The percussion firing apparatus of claim 22 wherein there is provided a single-fire safety means interposed intermediate said firing pin and said pressure balancing piston; said single-fire safety means allowing arming said hammer pin assembly such that said downward force on said pressure balancing piston will cause said firing pin to attempt ignition of said igniter means; said single-fire safety means also effecting disarming of said hammer pin assembly after one said attempt.

Claim 27

The percussion firing apparatus of Claim 24 wherein said single-fire safety means comprises a hammer pin; a hammer pin skirt defining a path directing said hammer pin to said firing pin; said hammer pin being slidably disposed within said hammer pin skirt; and a releasable hammer pin retainer means retaining said hammer pin at the upper portion of said hammer pin skirt prior to attempting ignition of said igniter means by striking said firing pin with said hammer pin; said releasable hammer pin retainer means releasing said hammer pin for striking said firing pin when subjected to sufficient downward force.

Claim 28

The percussion firing apparatus of claim 25 wherein said releasable hammer pin retainer means comprises a shear pin extending laterally through said hammer pin skirt and at least into said hammer pin; and said hammer pin skirt has a top portion that closely and conformingly fits the exterior of the bottom of the hammer pin and has an enlarged bore immediately therebelow for preventing any dragging and fluid compression effects and allowing free and rapid downward movement of the hammer pin once the shear pin has been sheared.

Claim 29

The percussion firing apparatus of claim 25 wherein said arming means includes a releasable piston retainer means for retaining said pressure balancing piston in place with respect to said hammer pin prior to moving downwardly for effecting firing; and includes a biasing means intermediate said hammer pin and said pressure balancing piston for storing a predetermined amount of energy for accelerating said hammer pin once said respective releasable piston and hammer pin retainer means have been released to ensure that said firing pin is struck sufficiently hard to effect ignition of said igniter means.

Claim 30

The percussion firing apparatus of claim 27 wherein said single-fire safety means includes a shoulder on said hammer pin skirt and a stop ring at the lower end of said biasing means for preventing downward movement of the lower end of said biasing means beyond said hammer pin skirt whereby downward force on said hammer pin and said firing pin cannot be exerted by said biasing means after said single attempt at firing.

Claim 31

The percussion firing apparatus of claim 28 wherein said biasing means comprises a spring; and said hammer pin and said shoulder are so designed that said stop ring encounters said shoulder before said hammer pin encounters said firing pin whereby said hammer pin is accelerated by said spring, said spring is prevented from acting upon said hammer pin all the way to said firing pin, and said hammer pin relies upon inertial force to strike said firing pin with the correct force.

Claim 32

The percussion firing apparatus of claim 28 wherein said single-fire safety also includes an exteriorly protruding shoulder on said pressure balancing piston and an interiorly protruding shoulder for limiting downward motion of said pressure balancing piston to prevent its imposing a force on said firing pin by way of said hammer pin after said releasable hammer pin retaIner means has been released for firing.

Claim 33

The percussion firing apparatus of claim 21 wherein said pressure balancing piston has an upwardly protruding member that is adapted to be acted on for moving said pressure balancing piston downwardly for effecting arming and firing.

Claim 34

The percussion firing apparatus of claim 31 wherein a fishing neck means is disposed at the upper end of said percussion firing apparatus and is adapted for being suspended from a tubing string for emplacement in and removal from said well.

Claim 35

The percussion firing apparatus of claim 32 wherein said fishing neck means includes an internal fish neck; a housing defines a prong-receiving chamber surrounding said upwardly protruding member on said pressure balancing piston; and apertures are provided in said housing, said apertures having downwardly and outwardly inclined surfaces for draining off trash, debris and the like.

Claim 36

The percussion firing apparatus of claim 33 wherein a simple one-piece prong is incluDed, said prong having a connection means at its upper end for connection with a means for imposing a downward force; said prong being adapted to fit inside said fishing neck means and having its lower end adapted to contact said upwardly protruding member of said pressure balancing piston for forcing it downwardly.

Claim 37

The percussion firing apparatus of claim 21 wherein said firing pin has a controlled penetrating depth feature that assures adequate penetration for ignition but acts as a safety feature in instances where ignition fails to occur.

Claim 38

The percussion firing apparatus of claim 35 wherein said controlled penetrating depth feature includes an enlarged head on said firing pin, said enlarged head having a relatively large flat bottom surface for encountering a second flat surface to limit downward movement thereof; and said firing pin is disposed in an aperture that is surrounded at its upper end by a second, relatively large, flat surface for stopping downward movement of said enlarged head and said firing pin.

Claim 39

The percussion firing apparatus of claim 21 wherein said pressure balancing piston is disposed in said pressure balancing chamber; first and second bores communicate with respective ends of said pressure balancing chamber, said first bore communicating with the exterior of said percussion firing apparatus and said second bore communicating interiorly thereof with said firing pin chamber; said pressure balancing piston having an upwardly extending member disposed in said first bore and having a first cross sectional area that is exposed to pressure exteriorly of said percussion firing apparatus; said pressure balancing piston having a large central portion having a second cross sectional area; an aperture communicating with said pressure balancing chamber near its end closest to said second bore and communicating exteriorly of said percussion firing apparatus for exposing the lower portion of said pressure balancing chamber to pressure exteriorly of said percussion firing apparatus; said pressure balancing piston having a lower end disposed in said second bore such that said pressure balancing piston is slidable longitudinally of said first and second bores and said pressure balancing chamber; said pressure balancing piston having a longitudinally extending internal passageway communicating intermediate said second bore and an upper portion of said pressure balancing chamber intermediate said enlarged portion of said pressure balancing piston and said first bore for exposing the upper portion of said pressure balancing chamber to pressure interiorly of said percussion firing apparatus; said lower end of said pressure balancing piston having a third cross sectional area; said second cross sectional area being enough larger than said first and third cross sectional areas that pressure interiorly of said percussion firing apparatus will act on exposed said third area and the top exterior portion of said second area and the pressure exteriorly of said percussion firing apparatus will act on said first area and the bottom exterior portion of said second area to create equal and opposing forces that neutralize each other such that said pressure balancing piston is moved responsive to a force other than pressure and the effects of pressure are neutralized.

Claim 40

The percussion firing apparatus of claim 21 wherein an elongate detonation passageway is disposed intermediate said igniter means and said first connection means for downward passage of the shock wave from the ignited igniter means; and wherein a shooting adapter and a booster pellet are connected with said first connection means and have a third connection means similar to said first connection means for connecting with a device that is actuated responsive to firing of said booster pellet.