Claims
- 1. Firing appartus for use with a well perforating gun of the type having a carrier containing a plurality of shaped-charges, and detonating means for actuating said charges, comprising:
- a tubular housing adapted to be connected to said carrier;
- firing pin means mounted in said housing for movement from a first position spaced from said detonating means to a second position impacting said detonating means, said firing pin means having a transverse cross-sectional area subject to well pressure to cause such movement;
- releasable means for locking said firing pin means in said first position; and
- differential pressure responsive means for releasing said locking means to enable said well pressure to move said firing pin means to said second position;
- wherein said locking means comprises laterally shiftable latch means on said housing, said latch means being movable from an inner position engaging detent means in said firing pin means to an outer position disengaged from said detent means, and locking surface means on said differential pressure responsive means normally engaging said latch means for preventing movement thereof to said outer position.
- 2. The apparatus of claim 1 wherein said differential pressure responsive means includes piston means sealingly arranged within cylinder means in said housing, said locking surface means being formed on said piston means, said piston means being movable from an upper position where said locking surface means engages said latch means to a lower position where said locking surface means is disengaged from said latch means, and shear means for retaining said piston means in said upper position, said shear means being disrupted in response to downward force of a predetermined magnitude.
- 3. The apparatus of claim 2 wherein said piston means has upwardly and downwardly facing transverse pressure surfaces, and further including first port means for communicating the pressure of well fluids adjacent said housing to said downwardly facing pressure surface, and second port means for communicating an applied fluid pressure to said upwardly facing pressure surface, whereby a differential fluid pressure can be applied to said piston means to generate the downward force necessary to disrupt said shear means.
- 4. A well perforating system, comprising:
- a packer for isolating an interval of a well bore;
- a pipe string associated with the packer for establishing fluid communication between the isolated interval and the well surface;
- a perforating device, including a detonator, suspended below the packer and adapted when fired to perforate the well in the isolated interval; and
- a firing mechanism including a housing associated with the perforating device, a firing element mounted within the housing for firing the detonator, and a locking mechanism mounted relative to the housing for movement from a first position in which operation of the firing element is inhibited to a second position in which operation of the firing element is permitted;
- means for moving the locking mechanism from the first to the second position in response to a first predetermined pressure difference; and
- means for operating the firing element in response to a second predetermined pressure difference.
- 5. A system as in claim 4, further comprising valve means connected in the pipe string and responsive to a third predetermined pressure difference for controlling the establishment of fluid communication between the isolated interval and the well surface.
- 6. A firing apparatus for use with a well perforating system including a packer for isolating an interval of a well bore; a pipe string associated with the packer for establishing fluid communication between the isolated interval and the well surface; and a perforating device, including a detonator, suspended below the packer and adapted when fired to perforate the well in the isolated interval; comprising:
- a housing adapted to be associated with the perforating device;
- a firing element mounted within the housing for firing the detonator; and
- a locking mechanism mounted relative to the housing for movement from a first position in which operation of the firing element is inhibited to a second position in which operation of the firing element is permitted;
- means for moving the locking mechanism from the first to the second position in response to a first predetermined pressure difference, and
- means for operating the firing element in response to a second predetermined pressure difference.
- 7. A system as in claim 4, 5 or 6, wherein the first predetermined pressure difference is a predetermined difference between the pressure of fluid in the isolated interval and the pressure of fluid in an annulus defined between the pipe string and the walls of the well bore above the packer; and wherein the second predetermined pressure difference is a predetermined pressure difference between the pressure of fluid in the isolated interval and a reference pressure.
- 8. A system as in claim 7, wherein the locking mechanism comprises a piston, and the means for moving the locking mechanism comprises a shear pin connected between the housing and the piston, the shear pin being designed to break when the first pressure difference is applied across the piston.
- 9. A system as in claim 8, wherein the locking mechanism further comprises a laterally shiftable latch member movable from an inner position engaging the firing element to an outer position disengaged from the firing element, the piston including a projecting surface portion and being movable from a first position in which the projecting portion abuts the latch member to prevent outward movement thereof to a second position in which the projecting portion is removed from the latch member to permit outward movement thereof.
- 10. A system as in claim 9, wherein the reference pressure is atmospheric pressure; and wherein the firing element comprises a firing pin adapted to be driven against the detonator when the second predetermined pressure is applied across it.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of Upchurch U.S. patent application Ser. No. 369,209, filed Apr. 16, 1982, entitled "Pressure Responsive Perforating and Testing System."
US Referenced Citations (7)
Continuation in Parts (1)
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Number |
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369209 |
Apr 1982 |
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