Abstract: A perforating gun includes a charge tube having shaped charges affixed thereto. Each shaped charge includes a radially outward pointing post adapted to receive a detonator cord. A retention member installed on the post provides a compressive force that energetically couples the detonator cord to the post. The radially outermost portion of the retention member is radially flush with or radially recessed relative to the radially outermost portion of each post. In one embodiment, the retention member has a rounded medial portion, a central opening and a pair of locking tabs that point radially inward to the central opening. Each post may include a slot for receiving the detonator cord and a circumferential groove that is adapted to receive the locking tabs.

Abstract: An apparatus for selectively isolating a firing head associated with a perforating gun may include an igniter coupled to a firing head, a time delay module coupled to the igniter and generating a pressure pulse after being activated by the igniter, a metering module, and a second firing head. The metering module may be coupled to the time delay module and including a housing having a bore and at least one opening exposed to a wellbore annulus. A piston disposed in the housing bore may have at least one passage. The piston is axially displaced from a first position to a second position by the generated pressure pulse. The second firing head is coupled to the metering module and is in fluid communication with the housing bore. The piston blocks fluid communication from the at least one opening of the housing and the second firing head in a first position and allows fluid communication from the at least one opening of the housing to the second firing head in the second position.

Abstract: A perforating gun includes a charge tube having shaped charges affixed thereto. Each shaped charge includes a radially outward pointing post adapted to receive a detonator cord. A retention member installed on the post provides a compressive force that energetically couples the detonator cord to the post. The radially outermost portion of the retention member is radially flush with or radially recessed relative to the radially outermost portion of each post. In one embodiment, the retention member has a rounded medial portion, a central opening and a pair of locking tabs that point radially inward to the central opening. Each post may include a slot for receiving the detonator cord and a circumferential groove that is adapted to receive the locking tabs.

Abstract: A perforating gun includes a charge tube having shaped charges affixed thereto. Each shaped charge includes a radially outward pointing post adapted to receive a detonator cord. A retention member installed on the post provides a compressive force that energetically couples the detonator cord to the post. The radially outermost portion of the retention member is radially flush with or radially recessed relative to the radially outermost portion of each post. In one embodiment, the retention member has a rounded medial portion, a central opening and a pair of locking tabs that point radially inward to the central opening. Each post may include a slot for receiving the detonator cord and a circumferential groove that is adapted to receive the locking tabs.

Abstract: An apparatus for detonating an explosive body associated with a downhole tool includes a plurality of firing heads, each firing head including an initiating explosive body generating a high-order input when detonated; and a funnel configured to detonate the explosive body associated with the downhole tool by using a single high-order output. The funnel has a body that includes: a plurality of input openings, each input opening positioned next to an associated initiating explosive body to receive the generated high-order input, a single output opening, and a flow path connecting the plurality of input openings with the single output opening.

Abstract: An interrupter for use with a wellbore tool may include a housing having an interior and a fusible body disposed in the housing interior. The fusible body may be solid below a specified temperature and liquid above the specified temperature. The fusible body communicates a first high-order detonation to a detonator only when liquid. The communicated the first high-order detonation is at a magnitude sufficient to cause the detonator to produce a second high-order detonation.

Abstract: An apparatus for selectively activating a downhole tool by using a shockwave generated by a detonator assembly may include an outer housing having a bore and an inner housing disposed in the bore of the outer housing. The inner housing may include a chamber having at least one canted surface, an inlet communicating with the chamber and being positioned between the chamber and the detonator assembly, an outlet communicating with the chamber and being positioned between the chamber and the downhole tool, and an energy blocker disposed in the chamber and being freely movable in the chamber as the inner housing changes orientation relative to a vertical datum. The energy blocker axially aligns with the inlet and the outlet when the inner housing is angularly offset less than a specified amount relative to a vertical datum.

Abstract: An apparatus for detonating an explosive body associated with a downhole tool includes a plurality of firing heads, each firing head including an initiating explosive body generating a high-order input when detonated; and a funnel configured to detonate the explosive body associated with the downhole tool by using a single high-order output. The funnel has a body that includes: a plurality of input openings, each input opening positioned next to an associated initiating explosive body to receive the generated high-order input, a single output opening, and a flow path connecting the plurality of input openings with the single output opening.

Abstract: An interrupter for use with a wellbore tool may include a housing having an interior and a fusible body disposed in the housing interior. The fusible body may be solid below a specified temperature and liquid above the specified temperature. The fusible body communicates a first high-order detonation to a detonator only when liquid. The communicated the first high-order detonation is at a magnitude sufficient to cause the detonator to produce a second high-order detonation.

Abstract: An apparatus for selectively isolating a firing head associated with a perforating gun may include an igniter coupled to a firing head, a time delay module coupled to the igniter and generating a pressure pulse after being activated by the igniter, a metering module, and a second firing head. The metering module may be coupled to the time delay module and including a housing having a bore and at least one opening exposed to a wellbore annulus. A piston disposed in the housing bore may have at least one passage. The piston is axially displaced from a first position to a second position by the generated pressure pulse. The second firing head is coupled to the metering module and is in fluid communication with the housing bore. The piston blocks fluid communication from the at least one opening of the housing and the second firing head in a first position and allows fluid communication from the at least one opening of the housing to the second firing head in the second position.

Abstract: A perforating gun train for perforating two or more zones of interest includes two or more gun sets made up of guns, one or more activators, and other associated equipment. An illustrative apparatus may include a first perforating gun; an activator responsive to the firing of the first perforating gun and a fuse element detonated by the activator; and a second perforating gun that is fired by the fuse element. An illustrative method for perforating a subterranean formation may include forming a perforating gun train using at least a first perforating gun and a second perforating gun; and energetically coupling the first perforating gun and the second perforating gun with an activator.

Abstract: A perforating gun train for perforating two or more zones of interest includes two or more gun sets made up of guns, one or more activators, and other associated equipment. An illustrative apparatus may include a first perforating gun; an activator responsive to the firing of the first perforating gun and a fuse element detonated by the activator; and a second perforating gun that is fired by the fuse element. An illustrative method for perforating a subterranean formation may include forming a perforating gun train using at least a first perforating gun and a second perforating gun; and energetically coupling the first perforating gun and the second perforating gun with an activator.

Abstract: A perforating gun train for perforating two or more zones of interest includes two or more gun sets made up of guns, detonators, and other associated equipment. In one embodiment, the gun sets are connected with connectors that can convey activation signals between the gun sets. The firing of a gun set creates this conveyed activation signal either directly or indirectly. In one arrangement, a surface signal initiates the firing of a first gun set while subsequent firings are initiated by firing of the gun sets making up the gun train. An exemplary connector is at least temporarily filled with signal conveyance medium adapted to transmit activation signals between the gun sets. In one embodiment, the signal conveyance medium is a liquid. The liquid can be added to the connector either at the surface or while in the wellbore.

Abstract: A perforating gun includes a charge tube having shaped charges affixed thereto. Each shaped charge includes a radially outward pointing post adapted to receive a detonator cord. A retention member installed on the post provides a compressive force that energetically couples the detonator cord to the post. The radially outermost portion of the retention member is radially flush with or radially recessed relative to the radially outermost portion of each post. In one embodiment, the retention member has a rounded medial portion, a central opening and a pair of locking tabs that point radially inward to the central opening. Each post may include a slot for receiving the detonator cord and a circumferential groove that is adapted to receive the locking tabs.

Abstract: An apparatus for controlling a wellbore energy train may include a firing head, a detonator cord associated with the firing head, and a plurality of serially aligned modules. Each module may include an enclosure, a first portion of a high order detonation material positioned at one end of the enclosure, a second portion of the high order detonation material positioned at the other end of the enclosure, and a low order detonation material interposed between the first portion and the second portion. A method for controlling an energy train generated in a wellbore may include serially aligning a plurality of the modules along the path of the energy train, and detonating at least one of the plurality of modules by detonating a detonator cord.

Abstract: A perforating gun train for perforating two or more zones of interest includes two or more gun sets made up of guns, one or more activators, and other associated equipment. An illustrative apparatus may include a first perforating gun; an activator responsive to the firing of the first perforating gun and a fuse element detonated by the activator; and a second perforating gun that is fired by the fuse element. An illustrative method for perforating a subterranean formation may include forming a perforating gun train using at least a first perforating gun and a second perforating gun; and energetically coupling the first perforating gun and the second perforating gun with an activator.

Abstract: An apparatus for controlling a wellbore energy train may include a firing head, a detonator cord associated with the firing head, and a plurality of serially aligned modules. Each module may include an enclosure, a first portion of a high order detonation material positioned at one end of the enclosure, a second portion of the high order detonation material positioned at the other end of the enclosure, and a low order detonation material interposed between the first portion and the second portion. A method for controlling an energy train generated in a wellbore may include serially aligning a plurality of the modules along the path of the energy train, and detonating at least one of the plurality of modules by detonating a detonator cord.

Abstract: A tubing conveyed perforating apparatus is shown which includes a tubular firing section which carries a plurality of explosive charges. The explosive charges are initially aligned with regions of reduced wall area provided in a tubular firing section which initially surrounds the charges. A piston sleeve is mounted on the exterior of the firing section. The piston sleeve has a plurality of apertures which are initially aligned with the regions of reduced wall area in the tubular firing section and thus with the explosive charges. Detonation of the charges causes the piston sleeve to shift so that the piston sleeve apertures are out of alignment with openings formed in the tubular firing section by the detonation of the charges, thereby trapping any resulting debris within the interior of the tubular firing section. Firing of the explosive charges opens upper and lower circulating ports so that sand or other debris can be reverse circulated up the interior of the well string to the well surface.

Abstract: A method and apparatus of activating electric wireline firing systems in which a firing pin is restrained against movement toward a detonator until application of sufficient voltage to the apparatus. The firing pin is not permitted to move immediately upon application of voltage to the apparatus thereby providing a period during which voltage may be interrupted to prevent detonation of the system. The requisite voltage which must be applied to the apparatus is relatively high thereby ensuring against premature detonation of the system due to high radio frequencies, stray voltages or other electrical influences.

Abstract: An apparatus and method for controlling the pressure at which a fluid is introduced into a well penetrating a subterranean formation. The apparatus comprises a blow out sub having a sealed chamber between two plugs. The chamber is filled with a fluid at a known pressure. Thus, the pressure required to release the first plug is independent of the pressure in the well below the sub. The sub is attached to a tubular and positioned within the well. The first plug is then released upon application of a predetermined pressure fluid pressure, and the second plug is released upon application of a lesser pressure. The blow out sub may additionally comprise a tube forming a channel through the first plug, the chamber, and the second plug, with a means for controlling fluid flow through the channel. A first fluid may be introduced into the well via the channel prior to releasing the first plug.