Method and apparatus for firing borehole perforating apparatus

Claim 3

The method of claim 1 further comprising the step of releasing the pressure within said tubing string subsequent to said arming of said firing assembly.

Claim 4

The method of claim 1 further comprising the step of lowering said firing assembly into engagement with said perforating gun disposed within said borehole.

Claim 5

Pressure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means associated with said housing member for arming said firing apparatus in response to a fluid pressure in said housing member; said arming means including a piston moveable in a fluid chamber and fixed to said housing member by a shear member which is shearable in response to said fluid pressure, a striker fixed to said piston and spring biased to move in a direction for firing said perforating gun; metered fluid displacement means for restricting movement of said piston for delaying the firing of said perforating gun for a predetermined time period, said fluid displacement means including a fluid jet in said piston for transferring fluid in a metered manner from one side of said piston to another side thereof such that the movement of said piston is slow to thereby effect said firing delay; and means for releasing fluid pressure on one side of said piston after said delay to accelerate said striker toward said perforating gun.

Claim 6

Pressure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means associated with said housing member for arming said firing apparatus in response to a fluid pressure in said housing member; said arming means including a piston moveable in a fluid chamber and fixed to said housing member by a shear member which is shearable in response to said fluid pressure, a striker fixed to said piston and spring biased to move in a direction for firing said perforating gun; metered fluid displacement means for restricting movement of said piston for delaying the firing of said perforating gun for a predetermined time period, said fluid displacement means including a fluid jet in said piston for transferring fluid in a metered manner from one side of said piston to another side thereof such that the movement of said piston is slow to thereby effect said firing delay; and means for releasing fluid pressure on one side of said piston after said delay to accelerate said striker toward said perforating gun.

Claim 7

The pressure actuated apparatus of claim 4 wherein said means for arming further comprises: a first piston member movably disposed within said housing member, said first piston member being responsive to pressure; and a shear member connected to said first piston member, said shear member selected to break in response to a predetermined pressure on said first piston.

Claim 8

The pressure actuated apparatus of claim 5 wherein said means for delaying the firing of said perforating gun further comprises: a second piston member movably disposed within said housing member, said second piston member including a fluid passage therethrough; and a flow restrictor retained within said fluid passage for limiting the flow of fluid therethrough.

Claim 9

The pressure actuated apparatus of claim 4 wherein said means for releasing fluid pressure comprises a widened bore in said piston fluid chamber.

Claim 10

Apparatus adapted to be lowered into a borehole for firing a perforating gun disposed on a tubing string, comprising: an elongated housing member; a first piston disposed within said housing member, said first piston being slidable in response to pressure within said tubing string; a second piston coupled to said first piston, said second piston being slidably disposed within said housing member; means for decoupling said second piston from said first piston in response to said pressure; a rod member coupled to said second piston; biasing means disposed about at least a portion of said rod member for exerting a force on said rod member for longitudinal movement of said rod member and said second piston in response to the decoupling of said second piston from said first piston; and means for restricting the longitudinal movement of said rod member and said second piston for a predetermined time period after decoupling of said second piston from said first piston.

Claim 11

Apparatus adapted to be lowered into a borehole for firing a perforating gun disposed on a tubing string, comprising: an elongated housing member; a first piston disposed within said housing member, said first piston being slidable in response to pressure within said tubing string; a second piston coupled to said first piston, said second piston being slidably disposed within said housing member; means for decoupling said second piston from said first piston in response to said pressure; a rod member coupled to said second piston; biasing means disposed about at least a portion of said rod member for exerting a force on said rod member for longitudinal movement of said rod member and said second piston in response to the decoupling of said second piston from said first piston; and means for restricting the longitudinal movement of said rod member and said second piston for a predetermined time period after decoupling of said second piston from said first piston.

Claim 12

The apparatus of claim 8 further comprising an impact sensitive firing head coupled to said housing member including an impact firing pin substantially in line with said rod member

Claim 13

The apparatus of claim 9 wherein said firing head further comprises a grapple end portion for engaging said perforating gun.

Claim 14

The apparatus of claim 10 wherein said grapple end portion further comprises a plurality of fingers terminating with inwardly directed dogs.

Claim 15

The apparatus of claim 9 wherein said decoupling means further comprises a tensile bar coupled between said first and said second pistons.

Claim 16

The apparatus of claim 12 wherein said restricting means further comprises at least one flow restriction valve to restrict fluid flow across said second piston.

Claim 17

Presure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means for arming said firing apparatus in response to pressure, including a first piston member movably disposed within said housing member, said first piston member being responsive to a predetermined pressure; a shear member connected to said first piston member, said shear member selected to separate in response to said pressure on said first piston; fluid displacement means responsive to said arming means for delaying the firing of said perforating gun for a predetermined time period, including a second piston member movably disposed within said housing member, said second piston member including a fluid passage therethrough; and a flow restrictor retained within said fluid passage for limiting the flow of fluid therethrough.

Claim 18

Presure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means for arming said firing apparatus in response to pressure, including a first piston member movably disposed within said housing member, said first piston member being responsive to a predetermined pressure; a shear member connected to said first piston member, said shear member selected to separate in response to said pressure on said first piston; fluid displacement means responsive to said arming means for delaying the firing of said perforating gun for a predetermined time period, including a second piston member movably disposed within said housing member, said second piston member including a fluid passage therethrough; and a flow restrictor retained within said fluid passage for limiting the flow of fluid therethrough.

Claim 19

Pressure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means associated with said housing member for arming said firing apparatus in response to a fluid pressure in said housing member, said arming means including a first piston member movably disposed within said housing member, said first piston member being responsive to pressure, and a shear member connected to said first piston member, said shear member selected to separate in response to a predetermined pressure on said first piston; and metered fluid displacement means for restricting movement of said firing apparatus for delaying the firing of said perforating gun for a predetermined time period, said means for restricting including a second piston member movably disposed within said housing member, said second piston member including a fluid passage therethrough, and a flow restrictor retained within said fluid passage for limiting the flow of fluid therethrough.

Claim 20

Pressure actuated apparatus for firing a perforating gun disposed within a borehole, comprising: an elongated housing member; means associated with said housing member for arming said firing apparatus in response to a fluid pressure in said housing member, said arming means including a first piston member movably disposed within said housing member, said first piston member being responsive to pressure, and a shear member connected to said first piston member, said shear member selected to separate in response to a predetermined pressure on said first piston; and metered fluid displacement means for restricting movement of said firing apparatus for delaying the firing of said perforating gun for a predetermined time period, said means for restricting including a second piston member movably disposed within said housing member, said second piston member including a fluid passage therethrough, and a flow restrictor retained within said fluid passage for limiting the flow of fluid therethrough.