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A method and apparatus effecting the perforating of a well casing and the gravel packing of the perforated areas of the well casing with one trip into the well of a combined perforating and gravel packing apparatus. This desirable objective is accomplished by a perforating gun construction permittin

A method and apparatus effecting the perforating of a well casing and the gravel packing of the perforated areas of the well casing with one trip into the well of a combined perforating and gravel packing apparatus. This desirable objective is accomplished by a perforating gun construction permitting complete flexibility to adjust in the field the number of horizontally and vertically spaced shaped charges through the provision of a polygonal carrier having vertically spaced holes provided in each of its planar sides to accommodate vertically spaced horizontal groups of shaped charges with the charges in one horizontal group being angularly displaced relative to the charges in a vertically adjacent horizontal group. Additionally, the crossover mandrel employed in the gravel packing operation provides, in its run-in position, a continuous axial passage through its entire length, permitting a detonating device to be placed therethrough to actuate the perforating gun. Subsequent to the perforating operation, a ball is dropped and seated on an annular sleeve carried within the hollow mandrel which permits the development of internal pressure within the mandrel. Such internal pressure is employed not only to effect the setting of a fluid pressure actuated packer but also to shift the ball supporting sleeve downwardly and uncover a crossover port in the mandrel which permits the gravel packing operation to be carried out conventionally.

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1. In an apparatus for use in a well bore and adapted to be run into the well casing on a tubular work string and in a single run-in of said string in said well accomplish perforation of the well casing adjacent a production zone and placement of a gravel pack in the casing adjacent the interior of

1. In an apparatus for use in a well bore and adapted to be run into the well casing on a tubular work string and in a single run-in of said string in said well accomplish perforation of the well casing adjacent a production zone and placement of a gravel pack in the casing adjacent the interior of the casing perforations, comprising, in combination: an axially elongated tubular liner assembly including a hollow screen element; a first packer secured to the lower end of said tubular liner assembly below said hollow screen, said first packer being initially settable in engagement with the casing bore at a position above the production zone; a tubular housing assembly secured in concentric depending relation to said first packer by a conduit, said tubular housing assembly defining a vertical axis, cylindrical chamber to house perforating charges, the top end of said chamber including a percussion operated detonator; a tubular carrier of polygonal cross sectional configuration concentrically insertable in said chamber, said carrier having N faces where N is an even number in excess of four; means for positioning said carrier in fixed equispaced relationship to the cylindrical wall of said cylindrical chamber; each of the N faces of said carrier having vertically spaced apertures for mounting thereon a selected number of shaped charge containers in a vertical array, there being only N/2 apertures having their axes disposed in a common horizontal plane at the level of each aperture, whereby the shaped charge containers may be positioned in a plurality of vertically spaced, horizontal groups with the shaped charge containers in each horizontal group angularly displaced from the shaped charge containers in the vertically adjacent group; means responsive to said percussion operated detonator for discharging all said shaped charges contained in each said horizontal group; a second packer secured to the upper end of said tubular liner assembly; a work string supported setting tool releasably connected to said packer; a hollow crossover mandrel assembly depending from said setting tool; said setting tool having pressure responsive means for expanding said second packer into sealing engagement with the well casing, said crossover mandrel assembly being insertable in said liner assembly; said first and second packers, said liner, said hollow crossover mandrel assembly and said conduit defining, in their run-in position, a continuous axial passage to permit dropping an activating means onto said percussion operated detonator to discharge same and perforate the casing by said shaped charges; said first packer being subsequently releasable from its set position, lowered below the casing perforations by the work string and resettable in said lowered position; a ball valve seat sleeve mounted in the bore of said hollow mandrel assembly; means for retaining said sleeve in an initial run-in position, said sleeve receiving a dropped ball in sealing relation after the perforating operation, thereby permitting build up of fluid pressure in the work string; said second packer being then expandable by said fluid pressure into sealing engagement with said casing above said casing above said perforations; said liner assembly and said hollow crossover mandrel assembly having flow passages and spaced sealing means selectively positionable upon movement of said ball valve seat sleeve downwardly relative to said second packer from said initial run-in position to a second position for directing gravel carrying fluid flowing downwardly through the work string into the well bore between said first and second packers, thence through said screen into the bottom of said crossover mandrel assembly, and thence outwardly into the well casing annulus at a point above said second packer, thereby permitting the packing of gravel around said hollow screen; and said ball valve seat sleeve being shiftable to said second position upon a further increase in fluid pressure in said work string. 2. The apparatus of claim 1 wherein said tubular carrier comprises a hexagonal extrusion of an extrudable metal. 3. The apparatus of claim 2 plus a primer cord depending from said detonator and positioned to be adjacent the inner end of each said shaped charge container. 4. The apparatus defined in claim 1, 2 or 3 further comprising a flapper valve pivotally mounted in the hollow crossover mandrel assembly at a position below the initial run-in position of said ball valve seat sleeve, an annular horizontal seat around the bore of said hollow crossover mandrel assembly cooperable with said flapper valve to close said bore to downward fluid flow, resilient acans urging said flapper valve to its closed position, latching means for holding said flapper valve in a vertical open run-in position, and means responsive to the downward displacement of said ball valve seat sleeve from its run-in position for releasing said latching means to permit said flapper valve to close. 5. The apparatus defined in claim 1, 2 or 3 wherein a frangible barrier traverses said conduit, said conduit having a plurality of radial ports immediately adjacent said frangible barrier to permit flushing of well trash from the surface of said frangible barrier. 6. In an apparatus for use in a well bore and adapted to be run into the well casing on a tubular work string and in a single run-in of said string in said well accomplish perforation of the well casing adjacent a production zone and placement of a gravel pack in the casing adjacent the interior of the casing perforation, comprising, in combination: an axially elongated tubular liner assembly including a hollow screen element; a first packer secured to the lower end of said tubular liner assembly below said hollow screen, said first packer being initially settable in engagement with the casing bore at a position above the production zone; a tubular housing assembly secured in concentric depending relation to said first packer by a conduit, said tubular housing assembly defining a sealed, vertical axis, cylindrical chamber to house perforating charges, the top end wall of said chamber including a percussion operated detonator; a tubular carrier of polygon cross sectional configuration concentrically insertable in said chamber, said carrier having N faces where N is an even number in excess of four; means for positioning said carrier in concentric relationship to the cylindrical wall of said sealed cylindrical chamber; a plurality of shaped charge containers of generally cylindrical configuration and each having a peripheral flange adjacent the discharge end, each of the faces of said polygonal tubular carrier having a plurality of vertically spaced apertures respectively proportioned to snugly receive one of said shaped charge containers therein with said peripheral flanges respectively abutting the outer faces of said polygonal tubular carrier, there being N/2 apertures having their axes disposed in each of a plurality of vertically spaced horizontal planes, whereby the shaped charge containers are positioned in a plurality of vertically spaced, horizontal groups with the shaped charge containers in each horizontal group angularly displaced from the shaped charge containers in the vertically adjacent group; means responsive to said percussion operated detonator for concurrently discharging all said shaped charges contained in each said horizontal group; a second packer secured to the upper end of said tubular liner assembly; a work string supported setting tool releasably connected to said second packer, a hollow crossover mandrel assembly depending from said setting tool, said setting tool having pressure responsive means for expanding said second packer into sealing engagement with the well casing, said crossover mandrel assembly being insertable in said liner assembly; said first and second packers, said liner, said hollow crossover mandrel assembly and said conduit defining, in their run-in position, a continuous axial passage to permit dropping an activating means onto said percussion operated detonator to discharge same and perforate the casing by said shaped charges; said first packer being subsequently releasable from its set position, lowered below the casing perforations by the work string and resettable in said lowered position; a ball valve seat sleeve mounted in the bore of said hollow mandrel assembly; means for retaining said sleeve in an initial run-in position; said sleeve receiving a dropped ball in sealing relation after the perforating operation, thereby permitting build up of fluid pressure in the work string; said second packer being then expandable by said fluid pressure into sealing engagement with said casing above said perforations; said liner assembly and said hollow crossover mandrel assembly having flow passages and spaced sealing means selectively positionable upon movement of said ball valve seat means downwardly relative to said second packer from said initial run-in position to a second position for directing gravel carrying fluid flowing downwardly through the work string into the well bore between said first and second packers, thence through said screen into the bottom of said crossover mandrel assembly, and thence outwardly into the well casing annulus at a point above said second packer, thereby permitting the packing of gravel around said hollow screen; said ball vable seat sleeve being shiftable to said second position upon a further increase in fluid pressure in said work string. 7. The apparatus of claim 6 wherein said tubular carrier comprises a hexagonal extrusion of an extrudable material. 8. The apparatus of claim 6 plus a primer cord depending from said detonator and positioned adjacent an inner end of each said shaped charge container. 9. The apparatus defined in claim 6, 7 or 8 wherein a frangible barrier traverses said conduit, said conduit having a plurality of radial ports immediately adjacent said frangible barrier to permit flushing of well trash from the surface of said frangible barrier. 10. The apparatus defined in claim 6 further comprising a flapper valve pivotally mounted in the hollow crossover mandrel assembly at a position below the initial position of said ball valve seat sleeve, an annular horizontal seat around the bore of said hollow crossover mandrel assembly cooperable with said flapper valve to close said bore to downward fluid flow, resilient means urging said flapper valve to its said closed position, latching means for holding said flapper valve in a vertical open run-in position, and means responsive to the downward displacement of said ball valve seat sleeve from its run-in position for releasing said latching means to permit said flapper valve to close. 11. A well casing perforating gun employing shaped explosive charges to perforate the well casing and adjacent formation, comprising an outer tubular housing assembly concentrically insertable in the well casing and defining a vertical axis cylindrical chamber, a tubular carrier of polygonal cross sectional configuration insertable in said chamber, said carrier having N faces where N is an even number in excess of four, means for positioning said carrier in concentric relationship to the cylindrical wall of said cylindrical chamber, each of the N faces of said carrier having apertures for mounting a selected number of shaped charge containers in vertical array, whereby the shaped charge containers may be positioned in a plurality of vertically spaced, horizontal groups with the shaped charge containers in each horizontal group angularly displaced from the shaped charge containers in the vertically adjacent group, and means for discharging all said shaped charges contained in each said horizontal group. 12. The perforating gun of claim 11 wherein said tubular carrier comprises a hexagonal extrusion of an extrudable material. 13. The perforating gun of claim 11 or 12 wherein said tubular housing assembly includes an upper end wall, and impact actuated detonating means sealably mounted in said upper end wall. 14. The perforating gun of claim 11 or 12 wherein said tubular housing assembly includes an upper end wall, impact actuated detonating means sealably mounted in said upper end wall, and a primer cord depending from said detonating means and positioned adjacent an inner end of each said shaped charge container. 15. A well casing perforating gun employing shaped explosive charges to perforate the well casing and adjacent formation, comprising an outer tubular housing assembly concentrically insertable in the well casing and defining a vertical axis sealed cylindrical chamber, a tubular carrier of polygonal cross sectional configuration insertable in said chamber, said carrier having N faces where N is an even number in excess of four, means for positioning said carrier in concentric relationship to the cylindrical wall of said sealed cylindrical chamber, a plurality of shaped charge containers of generally cylindrical external configuration and having a peripheral flange adjacent the discharge end, each of the faces of said polygonal tubular carrier having a plurality of vertically spaced apertures proportioned to snugly receive one of said shaped charge containers therein with said peripheral flange abutting the outer face of said carrier, said apertures being aligned to form horizontally aligned groups of vertically spaced apertures, there being N/2 shaped charge containers in each horizontal group, whereby the shaped charge containers may be positioned in a plurality of vertically spaced, horizontal groups with the shaped charge containers in each horizontal group angularly displaced from the shaped charge containers in the vertically adjacent group, and means for discharging all said shaped charges contained in each said horizontal group. 16. The perforating gun of claim 15 wherein said tubular carrier comprises a hexagonal extrusion of an extrudable metal. 17. The perforating gun of claim 15 or 16 wherein said tubular housing assembly includes an upper end wall, and impact actuated detonating means sealably mounted in said upper end wall. 18. The perforating gun of claim 15 or 16 wherein said tubular housing assembly includes an upper end wall, impact actuated detonating means sealably mounted in said upper end wall, and a primer cord depending from said detonating means and positioned adjacent an inner end of each of said shaped charge containers. 19. The well casing perforating gun of claim 11 or 15 wherein said tubular housing assembly includes an upper end wall supporting sleeve, an impact actuated detonating means transversely sealably mounted in said end wall supporting sleeve, conduit means extending above said end wall supporting sleeve; frangible barrier means traversing the bore of said conduit to protect said detonating means from contact by well debris; and port means in said conduit immediately adjacent said barrier means for flushing collected debris from said barrier means. 20. A combined method of perforating and gravel packing the production zone of a subterranean well with one trip of a work string comprising the steps of: (1) assembling on a tubular polygonal carrier a plurality of shaped charges with the charges arranged in vertically spaced, horizontal groups with the charges in one horizontal group being angularly displaced relative to the charges in the vertically adjacent horizontal group; (2) inserting the carrier with the charges assembled thereto within a vertical axis chamber defined by a tubular housing and sealing said chamber by means including a detonator at the upper end thereof; (3) assembling at the surface for attachment to the end of a tubular work string, a hollow liner assembly including a production screen, a first settable and releasable packer secured to the lower end of the hollow liner assembly, a hydraulically settable packer secured to the upper end of the hollow liner assembly, a pressure operated actuator releasably connected to the first packer, and a hollow crossover mandrel assembly connected to the actuator and insertable within the liner assembly and defining a horizontal annular valve seat intermediate the first and second packer; (4) connecting the tubular housing containing the spaced shaped charges in depending relationship to the first packer: (5) lowering the work string with the above listed assemblies thereon in the well until the spaced shaped charges are positioned adjacent to the desired production zone; (6) setting the first packer in a position immediately above the desired production formation with the spaced shaped charges adjacent the desired production zone: (7) dropping a detonating element through the hollow work string, the bore of the hollow mandrel assembly, and the first packer to energize the detonator, discharge the spaced shaped charges and perforate the casing; (8) releasing the first packer and lowering the work string to position the first packer below the perforated production zone, and then resetting said first packer; (9) inserting a valve element through the work string to sealingly seat on said annular valve seat in the hollow crossover mandrel assembly, thereby permitting fluid pressure to be built up within the work string: (10) increasing the fluid pressure in the work string to a level sufficient to cause the actuator to set the second packer; (11) increasing the fluid pressure in the work string to a level sufficient to cause the downward displacement of the valve element of said hollow crossover mandrel assembly and open a radial fluid passage from the bore of said hollow crossover mandrel to the bore of said liner assembly; and (12) introducing gravel carrying fluid through the work string to flow through passages defined by the hollow crossover mandrel and the hollow liner assembly downwardly along the casing annulus between said first and second packers, through the production screen, and upwardly through the crossover assembly to the casing annulus at a point above said second packer. 21. The method of claim 20 further comprising the step of permitting a flushing flow of formation fluids through the newly formed perforations prior to releasing and moving the first packer. 22. The method defined in claim 20 or 21 further comprising the step of removing the work string, the actuator and the hollow crossover mandrel assembly after completion of the gravel packing. 23. A well casing perforating gun employing shaped explosive charges to perforate the well casing and adjacent formations, comprising an outer tubular housing assembly concentrically insertable in the well casing and defining a vertical axis cylindrical chamber, a tubular carrier of polygonal cross sectional configuration insertable in said chamber, said carrier having N faces where N is an even number in excess of four, means for positioning said carrier in concentric relationship to the cylindrical wall of said cylindrical chamber, each of the N faces of said carrier having apertures for mounting a selected number of shaped charge containers in vertical array, whereby the shaped charge containers may be positioned in a plurality of vertically spaced, horizontal groups with the shaped charge containers in each horizontal group angularly displaced from the shaped charge containers in the vertically adjacent group. 24. A carrier for a plurality of shaped charge containers for a well perforating gun, said carrier comprising an elongated tubular element of polygonal cross-section having an even number of faces in excess of four; each of the faces of said polygonal carrier having vertically spaced apertures for mounting a selected number of shaped charge containers in vertical array, said apertures being positioned in a plurality of vertically spaced, horizontal groups with the apertures in each horizontal group angularly displaced from the apertures in the vertically adjacent group. 25. A perforating gun insertable in a well in a single trip of a production string and packer into the well comprising conduit means depending from the packer and having a bore communicable with the production string bore; a perforating gun suspended from said conduit means and having a percussion actuated firing head communicating with the bore of said conduit means, whereby a detonating bar may be dropped from the well surface through said conduit means to detonate said percussion actuated firing head, and a frangible barrier traversing the bore of said conduit means, thereby isolating said firing head from deposits of well trash, said conduit means having a plurality of radial ports adjacent said frangible barrier, some of said radial ports overlapping the upper surface of said frangible barrier to permit flushing of well trash from the surface of said frangible barrier.