Abstract: An apparatus (60) for absorbing a shock comprises a first tubular member (62) and a second tubular member (80) that are slidable positioned relative to one another. A plurality of layers (94-104) of energy absorbing members (88) extend radially from the second tubular member (80) such that movement of the second tubular member (80) in a first direction relative to the first tubular member (62) sequentially deforms the layers (94-104) of energy absorbing members (88). As the layers (94-104) are sequentially deformed, a subsequent layer (96) of energy absorbing members (88) begins to deform before the previous layer (94) of energy absorbing members (88) is completely deformed. The deformation of the energy absorbing members (88) absorbs the shock.

Abstract: A bi-directional explosive transfer subassembly (56) for coupling two explosive tools (52, 54) comprises first (74, 78) and second (76, 80) explosive carrying members that respectively define first (82, 86) and second (84) explosive cavities. A ball end (102) of the first explosive carrying member (74, 78) is slidingly received in a socket (114) of the second explosive carrying member (76, 80) such that the first (74, 78) and second (76, 80) explosive carrying members are rotatable and angularly displaceable relative to one another. A first explosive device (130) is disposed in the first explosive cavity (82, 86) and a second explosive device (132) is disposed in the second explosive cavity (84). The first (130) and second (132) explosive devices are spaced apart such that when one of the explosive devices (130, 132) is initiated, the other of the explosive devices (130, 132) will in turn be initiated.

Abstract: A detonation transfer subassembly for coupling two detonation activated tools in a work sting such that the work string may be severed between the two detonation activated tools without risk of a detonation is disclosed. The detonation transfer subassembly comprises first and second explosive carrying members having a detonation transfer member disposed therebetween. The detonation transfer member defines a longitudinal passageway therein. A firing pin is disposed within the longitudinal passageway. The firing pin has a first position proximate the first explosive carrying member and a second position proximate the second explosive carrying member. The firing pin is propellable from the first position to the second position following a detonation within the first explosive carrying member such that the firing pin impacts an explosive disposed within the second explosive carrying member, thereby transferring detonation from the first explosive carrying member to the second explosive carrying member.

Abstract: A tubular casing section for a subterranean well has side wall apertures therein which are temporally sealed with plug structures. The plugged casing section is positioned within a wellbore at a selected subterranean formation and cemented in place within the wellbore. The plugs are removed, such as by melting, fracturing, shearing or corrosion, and a stimulation tool is lowered into the casing and operated to pierce through the cement lining at the unplugged casing side wall apertures and into the surrounding subterranean formation to establish communication between the formation and the interior of the casing.

Abstract: Methods are provided which permit pressure tested multiple perforating gun modules to be interconnected into gun assemblies, without disturbing any pressure-bearing seals of the modules. Prior to assembling the gun assembly, the seals of the modules are pressure tested. The pressure tested modules are then connected to each other without disconnecting or otherwise breaking any of the pressure-bearing seals of the modules.

Abstract: A method of delaying detonation of an explosive device within a subterranean well is provided which is convenient, economical and efficient in its use. In addition, the safety of such operations is enhanced by the construction of a firing head used in the method and engaged with the explosive device in the well. In one described embodiment, the firing head includes a piston reciprocably received in a fluid chamber, and an orifice for metering fluid from the chamber. When the firing head is engaged with the explosive device, weight is applied to the piston, thereby forcing fluid from the chamber through the orifice and producing a time delay. After the piston has traveled a predetermined distance relative to the chamber, its further displacement is relatively unrestricted and the weight drives the piston downwardly to cause detonation of the explosive device.

Abstract: A bi-directional explosive transfer apparatus for use in connecting and orienting perforating guns in a well. The apparatus includes a connector having first and second housing portions which are pivotally attached to one another. First and second explosive devices in the connector provide a bi-directional explosive path between perforating guns joined by the connector. At least one orienting fin is attached to the perforating guns to position the guns off-center so that they will orient themselves by gravity in a deviated well section. The swivel connection provided by the connector allows the guns to rotate individually as necessary and relative to the other guns. A method of perforating a well using the apparatus is also disclosed.

Abstract: A system is provided for selectively perforating multiple zones in a well either simultaneously, or in series, having isolation barriers, or packers, located between the perforating multiple zones, without moving the system with respect to the well. The system includes a tubing string which carries at least a first and a second perforating gun. At least a first and a second pressure actuated firing head are associated with the first and second perforating guns, respectively. A first and second packer for isolating the perforating guns from each other. A source of actuating fluid pressure for the firing head is provided, which may be the bore of the tubing string. A first selective communication device is provided for isolating the second firing head from the source of actuating fluid pressure until after the first perforating gun has been fired, and for then communicating the second firing head with the source of actuating fluid pressure in response to firing of the first perforating gun.

Abstract: An apparatus and method for snubbing tubing-conveyed perforating guns in and out of a well bore. The apparatus includes a string of perforating guns wherein adjacent perforating guns are attached using a connector having an upper mandrel which is attached to a lower mandrel by left-hand threaded connection. A ratchet positioned on the upper mandrel allows left-hand rotation of the upper mandrel and ratchet with respect to the lower mandrel while preventing right-hand rotation of the ratchet with respect to the lower mandrel. Shear screws interconnecting the upper mandrel and the ratchet may be sheared upon application of a predetermined torque to allow right-hand rotation of the upper mandrel with respect to the ratchet. The lower mandrel has a recess or reduced diameter portion which is adapted for sealing engagement by a pipe ram in a blowout preventer.

Abstract: An actuating tool which is conveyed into a tubing string to attach to portions of an emplaced perforating gun. The tool includes an actuator with an electronic delay timer and an explosive device. The tool attaches to an emplaced perforating gun and detonates it by initiating an explosive charge along a complete explosive pathway formed between the actuator and gun, the actuator includes a tandem piston arrangement functional at most existing hydrostatic pressure levels, but nonfunctional at or near the surface of the wellbore. The tool may be withdrawn from the tubing string for a backup detonation tool to be placed into the tubing string to detonate a secondary firing head.

Abstract: A gun hanger for emplacement through a tubing string into a casing string, comprising an inner mandrel, a setting means slidably received on said mandrel, said setting means including a plurality of spaced apart, extendable slips mounted thereon such that operation of said setting means causes said slips to extend and engage the casing string, a slip release means slidably received on said mandrel such that operation of said slip release means causes said slips to retract and disengage from the casing string, said setting means and said release means having diameters less than the inside diameter of the tubing string when said slips are retracted, a centralizer mounted on and extending axially from the hanger, said centralizer comprising a stem and a plurality of evenly circumferentially spaced longitudinal bow springs flexibly mounted thereon, said bow springs being longitudinally spaced along said stem such that each spring longitudinally clears its preceding and succeeding springs when said springs are com

Abstract: Methods of perforating a well using coiled tubing conveyed perforating guns are disclosed. A perforating tool string includes a coiled tubing string, a perforating gun, a releasable gun hanger, and a pressure responsive release connecting the coiled tubing string to the perforating gun. The perforating tool string is lowered into place within the well and then the gun hanger is actuated by reciprocating motion of the coiled tubing string without rotating the coiled tubing string, thereby setting the gun hanger in the casing. Fluid pressure is then increased in the coiled tubing string to actuate the pressure responsive release to release the coiled tubing string from the perforating gun. The coiled tubing string and pressure responsive connector may then be retrieved from the well prior to firing the perforating gun. The perforating gun is subsequently fired by a pressure responsive firing head to perforate the well casing, and the perforating gun then automatically drops to the bottom of the well casing.

Abstract: A modular perforating gun system for use in perforating a well. The system comprises a lower perforating gun module or section which may be supported in a variety of ways adjacent to a well formation to be perforated. The system further comprises at least one additional perforating gun module or section which is positioned above the lower perforating gun module. After firing, any number of the perforating gun modules may be individually retrieved from the wellbore without killing the well and subsequently replaced as necessary.

Abstract: A system is provided for performing multiple operations on a well in response to multiple fluid pressure increases. The system includes first and second pressure actuated firing heads and a source of actuating fluid pressure for the firing heads. A first selective communication device is provided for isolating the second firing head from the source of actuating fluid pressure until after the first firing head has been actuated and for then communicating the second firing head with the source of actuating fluid pressure in response to actuation of the first firing head. This system is particularly adapted for allowing pressure testing of a well upon a first fluid pressure increase, followed by perforation of the well upon a second fluid pressure increase.

Abstract: A monobore completion system where the well is completed using a tubing conveyed perforating completion system having an automatic gun release and support for the tubing conveyed perforating guns.

Abstract: A firing head actuator for a perforating gun includes an atmospheric pressure chamber which is run into the well on a slick line. The atmospheric pressure chamber can then be communicated with a low pressure side of an actuating piston to move the piston and initiate firing of the perforating guns. Either pyrotechnic or electrical time delays may be built in to the firing head actuator.

Abstract: A well test string includes an annulus pressure responsive tester valve and a tubing conveyed perforating gun including a tubing pressure actuated time delay firing mechanism. A compression set packer is disposed in the test string between the tester valve and the perforating gun. The packer includes a bypass valve for communicating the well below the packer with the tubing bore. The bypass valve is operably associated with the packer so that the bypass valve is open prior to setting the packer and so that the bypass valve is closed as the packer is set. The compression set packer also includes a one-way equalizer valve for allowing one-way fluid flow from the well below the packer to the tubing bore. The equalizer valve is operably associated with a bypass valve so that the equalizer valve is inoperable when the bypass valve is open, and so that the equalizer valve is operable when the bypass valve is closed.

Abstract: A system is provided for selectively perforating multiple zones in a well on a single trip into the well. The system includes a tubing string which carries at least a first and a second perforating gun. At least a first and a second pressure actuated firing head are associated with the first and second perforating guns, respectively. A source of actuating fluid pressure for the firing head is provided, which may be the bore of the tubing string. A first selective communication device is provided for isolating the second firing head from the source of actuating fluid pressure until after the first perforating gun has been fired, and for then communicating the second firing head with the source of actuating fluid pressure in response to firing of the first perforating gun. The first firing head provides a time delay during which the actuating fluid pressure may be bled off prior to the firing of the first perforating gun.

Abstract: A perforating gun is supported from the lower end of a side pocket mandrel. The perforating gun includes a mechanical detonator which is received within the side pocket receptacle bore. The mechanical detonator is actuated in response to striking engagement by a kickover tool. The side pocket mandrel includes a longitudinal production bore which is connected in alignment with a string of production tubing. The perforating gun assembly is run in with the production tubing during initial installation of isolation packers, and the shoot is carried out while the well bore is in an underbalanced pressure condition.

Abstract: A pressure responsive below packer valve apparatus which allows operation of a below packer valve through application of pressure to the wellbore annulus above the packer. The valve apparatus includes a crossover located in a tool string above the packer which communicates upper annulus pressure to a conduit inside the tool string. This conduit communicates annulus pressure to a valve mechanism below the packer. A selectively releasable mechanism such as a rupture disk communicates pressure to the valve mechanism once a threshold pressure is reached, thereby facilitating operation of the valve mechanism through application of annulus pressure.