Abstract: A multiple acting lock is provided which prevents premature setting of the packer of a gravel pack tool by the setting piston of a setting tool. The lock comprises a locking cylinder which when in the locked position rotationally locks the setting tool with the gravel pack tool thereby allowing rotation of the tool during tripping to facilitate working the tool past tight spots. The lock also longitudinally locks the setting sleeve of the gravel pack tool to prevent premature setting of the packer of the gravel pack tool. The locking mechanism of the setting sleeve comprises keys located in keyholes and a sleeve inside the setting sleeve which protrude and engage with the setting sleeve. The locking cylinder when in a locked position covers the inside of the keyholes retaining the keys in engagement with the setting sleeve. When the locking cylinder is hydraulically moved to the unlocked position the keys slide inward out of the keyholes and out of engagement with the setting sleeve.

Abstract: A separable fluid pressure activated firing mehanism for a perforating gun comprises a pressure-operated tubing valve, a packer, and a tubular housing assembly defining a plurality of fluid pressure chambers therein. The first chamber contains a light density, clean, compressible fluid which is subject to well annulus pressure above the packer to provide a reference pressure. A second chamber sealably mounts a piston-type firing pin, which is normally secured by a locked latch in an elevated position above a detonatable primer and the lower portion of said firing pin is exposed to the reference pressure. The latch is unlocked through the application of a predetermined annulus pressure above the packer to a locking piston which moves to unlock the latch and trap the reference pressure in the first chamber. A further increase in said annulus pressure opens the tubing valve.

Abstract: Improved method and apparatus are provided for perforating casing located in a deviated portion of a subterranean well. The direction toward which the explosive charges in the downhole perforating gun are facing upon firing of the gun is accurately controlled by a firing head operatively responsive to a first initiating signal activated from the surface and a second signal automatically generated when the gun is rotationally at a predetermined angular position relative to a vertical plane passing through the central axis of the perforating gun. A rotating device within the gun firing head enables the gun to be rotated for generating the second signal when the gun is positioned below a set packer. The technique of the present invention is reliable yet relatively inexpensive, and minimizes undesirable gravitation of formation sands with formation fluids into the casing.

Abstract: A separable fluid pressure activated firing mechanism for a perforating gun comprises a pressure-operated tubing valve, a packer, and a tubular housing assembly defining a plurality of fluid pressure chambers therein. The first chamber contains a light density, clean, compressible fluid which is subject to well annulus pressure above the packer to provide a reference pressure. A second chamber sealably mounts a piston-type firing pin, which is normally secured by a locked latch in an elevated position above a detonatable primer and the lower portion of said firing pin is exposed to the reference pressure. The latch is unlocked through the application of a predetermined annulus pressure above the packer to a locking piston which moves to unlock the latch and trap the reference pressure in the first chamber. A further increase in said annulus pressure opens the tubing valve.

Abstract: A method and apparatus for effecting the assembly and arming a multisection perforating gun for a subterranean well. Each of the gun sections has a plurality of vertically and angularly spaced shaped charge containers disposed with the primer ends located in concentric fashion about the vertical axis of the gun, thus defining an axial passage communicating with the bores of hollow nipples which respectively effect securement of one gun section to the next adjacent gun section. In one modification, a continuous primer cord is stored on a reel below the lowermost gun section and is then pulled successively upwardly through each of the additional gun sections as they are assembled. In another modification, each of the gun sections is provided with a length of fusible guide tubing interposed between the inner primer ends of all of such shaped charges and the continuous length of primer cord is fed downwardly through the axial passage defined by such guide tubing.

Abstract: A high energy firing mechanism for a well perforating gun comprises a downwardly directed shaped charge which is discharged by an impact detonatable primer. The explosive jet developed by the downwardly directed shaped charge impinges upon a booster charge which in turn is connected to a primer cord leading to the shaped charges of a perforating gun. Sufficient detonating energy is produced to assure high energy detonation of the booster charge and primer cord, even though such elements may be formed from a thermal resistant explosive.

Abstract: A method and apparatus for effecting the firing of a perforating gun having a plurality of vertically spaced, shaped charges wherein the firing is accomplished from the lowermost shaped charge to the uppermost shaped charge. In one modification, the detonation of the shaped charges is accomplished by a primer cord extending through all the gun sections, which is detonated only by a booster charge located in the bottom portion of the perforating gun housing. The booster charge is in fluid communication with the interior of the housing and, upon the occurrence of leakage of well fluids into the housing, the booster charge is rendered ineffective, thus preventing the firing of the perforating gun when the lower portion of the gun is filled with well fluids. In another modification, a conventional primer cord with booster charges on each end is inserted in each gun section, as is a length of flame-transmitting tubing.

Abstract: A method and apparatus for effecting the assembly and arming a multisection perforating gun for a subterranean well. Each of the gun sections has a plurality of vertically and angularly spaced shaped charge containers disposed with the primer ends located in concentric fashion about the vertical axis of the gun, thus defining an axial passage communicating with the bores of hollow nipples which respectively effect securement of one gun section to the next adjacent gun section. In one modification, a continuous primer cord is stored on a reel below the lowermost gun section and is then pulled successively upwardly through each of the additional gun sections as they are assembled. In another modification, each of the gun sections is provided with a length of fusible guide tubing interposed between the inner primer ends of all of such shaped charges and the continuous length of primer cord is fed downwardly through the axial passage defined by such guide tubing.

Abstract: A well perforating apparatus includes an underbalancing valve for opening ports in a tubing string immediately subsequent to the firing of a perforating gun, and comprises a hollow conduit having at least one pair of axially aligned, and radial holes traversing the wall of the conduit. A frangible member has its end portions slidably and sealably mounted in such holes and is therefore disposed transversely to the path of a detonating bar which is dropped to initiate the firing of the perforating gun. Upon breakage of the frangible member, the ends of the bar are forced inwardly out of the holes by the fluid pressure differential existing between the interior and exterior of the conduit due to the underbalanced fluid pressure condition achieved in the tubing string prior to firing the perforating gun.

Abstract: A firing mechanism for a downhole perforating gun comprises two cooperating housing sections having closed end walls in abutment. The lower housing section contains a booster charge and the primer cord for firing the gun. The upper housing section contains a detonatable primer, a hammer, and a downwardly directed explosive charge positioned between the primer and the bottom end wall of the upper housing. The upper housing is secured to the lower housing by a collet latch which, if firing of the gun does not occur, can be released by the exertion of a substantial upward force on a fishing neck provided in the assemblage of the upper housing. The defective elements can then be repaired or replaced, the upper housing reinserted in the well by wireline, and latched into an operative position with respect to the lower housing to permit another attempt to fire the perforating gun.

Abstract: A redundant firing mechanism for a perforating gun utilized in subterranean wells comprises a hollow housing assembly incorporating two spaced primer charges disposed in vertically spaced relationship. A fluid pressure chamber is defined within the hollow housing assembly and is closed at the top end of the assembly by a frangible barrier disc. A fluid pressure actuated hammer is provided to impact upon the lowermost one of the primers in response to fluid pressure developed in the fluid pressure chamber. In the event that the lowermost primer does not detonate, a detonating bar may then be dropped through the tubing string to break the frangible barrier and impact upon a second hammer disposed in overlying relationship to the second primer.

Abstract: A compressed fluid pressure actuated firing mechanism for a well perforating gun comprises a hollow housing assembly defining a mounting for a primer, a hammer releasably secured above the primer for movement towards the primer, and a fluid pressure chamber associated with the hammer for effecting a compressed fluid pressure force on the latching mechanism for the hammer and on the hammer to move it into impact engagement with the primer. The fluid pressure applied to the hammer is produced by permitting a selected fluid pressure surrounding the fluid pressure chamber to be forced into the fluid pressure chamber through at least one unidirectional check valve, thus compressing the fluid pressure within the fluid pressure chamber. The upper portions of the hammer are in contact with this compressed fluid pressure and the lower portions of the hammer are in contact with the selected fluid pressure.

Abstract: A more reliable operation of a multisection perforating gun for a subterranean well is achieved by disposing a detonation-transmitting element in parallel relationship to the conventional arrangement of booster charges and primer cords by which the detonating energy is transmitted from one gun section to the next. In one embodiment the detonation-transmitting element extends adjacent the primer cord from the upper portion of a gun section to a medial portion of the primer cord in the gun section, where the bottom end of the detonation-transmitting element is secured to an auxiliary booster charge having sufficient detonating energy to effect the detonation of the medial portion of the primer cord. In another modification, the detonation-transmitting element is radially spaced from the primer cord and has a circular, radially disposed portion at its upper end which is ignited by the booster charge secured to the bottom end of the flame-transmitting element in the upwardly adjacent section.

Abstract: A method and apparatus for effecting the sealing of a well conduit comprises the positioning of a sealing plug unit within a special nipple provided in the well conduit and defining first and second surfaces and a seal bore. The sealing plug unit is provided with external seal elements cooperable with the seal bore and a first and second latching elements respectively cooperable with the first and second surfaces provided on the nipple. The sealing plug is actuated by first passing it downwardly through the nipple and then retracting it upwardly, whereupon the first of the latching elements engages with one of the surfaces on the nipple, thus preventing further upward movement on the assembly and permitting the application of a tensile force to release the plugging unit from the remainder of the unit to bring a camming sleeve into engagement with the second latching element to cam such element outwardly into engagement with an upper recess of the nipple.

Abstract: A method and apparatus for effecting the perforation of a well casing and the adjoining production formation comprises a tubular housing communicating between a perforating gun housing and the lower end of a tubular string. The perforating gun housing which is adapted to be carriable by the tubular string contains an impact actuated firing head and the tubular housing contains a port normally closed by sleeve valve. The valve is biased towards an open position but is selectively secured in its closed position by a frangible restraining mechanism which extends into the free fall path of a detonating bar dropped through the tubular tool string and is removed by the detonating bar to initiate the opening of the port sleeve valve prior to impacting the firing head. In a modification, the sleeve valve is shifted to its open position by fluid pressure produced in the casing annulus subsequent to the firing of the perforating gun.

Abstract: The invention provides a subterranean well casing perforating gun device which employs shaped explosive charges to perforate the well casing. The device generally defines an outer tubular housing assembly concentrically insertable in the well and defining a vertical axis, cylindrical chamber. A tubular carrier of polygonal cross sectional configuration is insertable in the chamber in concentric relationship to the cylindrical wall of the cylindrical chamber. Each of the faces of the carrier have a plurality of spaced passages therethrough, each passage having a configuration substantially corresponding to the configuration of the polygonal face. A shaped charge container has its cylindrical body insertable in any selected one of the passages and a radial flange on the outer end for abutting the polygonal face portion adjacent the respective passage, thereby limiting the insertion of each of the containers into the selected passage.

Abstract: A method and apparatus effecting the perforating of a well casing and the gravel packing of the perforated areas of the well casing of a combined perforating and gravel packing apparatus. This desirable objective is accomplished by a perforating gun construction permitting complete flexiblility to adjust in the field the number of horizontally and veritcally 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.

Abstract: 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.

Abstract: A method and apparatus for releasing a subterranean well perforating gun from a tubular string after firing of the subterranean well perforating gun. The apparatus comprises two telescopically inter-related tubular assemblies which are interconnected for axial co-movement solely by a plurality of radially shiftable latching elements. Such latching elements are normally maintained in a locked position by an annular piston. One end of the annular piston is exposed to gas at surface ambient pressure and the other end is exposed to the gas pressure generated in the perforating gun by its discharge and subsequently to the well fluid pressures produced by flow of well fluids through the perforations. The movement of the annular piston under such fluid pressure forces permits the locking elements to be cammed radially inwardly and release the connection between the tubular tool string and the perforating gun without any action on the part of the operator.

Abstract: A method and apparatus are provided for angularly aligning normally vertical rows of explosive charge containers mounted on a tubing conveyed perforating gun carrier so that none of the explosive charges is directed substantially vertically upwardly in the event that perforation is accomplished in a non-vertical section of the well casing.