Oriented Perforating System

This application is a continuation application of U.S. patent application Ser. No. 18/354,597 filed on Jul. 18, 2023, which is a continuation application of U.S. patent application Ser. No. 17/834,417 filed on Jun. 7, 2022, which is a bypass continuation of International Application No. PCT/EP2020/085624 filed Dec. 10, 2020, which claims priority to U.S. Provisional Application No. 62/945,942 filed Dec. 10, 2019, U.S. Provisional Application No. 63/001,766 filed Mar. 30, 2020, and U.S. Provisional Application No. 63/003,222, filed Mar. 31, 2020, the contents of each of which are incorporated herein by reference. U.S. patent application Ser. No. 17/834,417 filed on Jun. 7, 2022 is also a bypass continuation-in-part of International Application No. PCT/EP2021/058182 filed Mar. 29, 2021, which claims priority to U.S. application Ser. No. 17/206,416 filed Mar. 19, 2021 (issued as U.S. Pat. No. 11,339,614 on May 24, 2022), U.S. Design application Ser. No. 29/759,466 filed Nov. 23, 2020 (issued as U.S. Pat. No. D922,541 on Jun. 15, 2015), U.S. Provisional Application No. 63/002,507 filed Mar. 31, 2020, and U.S. Design application Ser. No. 29/729,981 filed Mar. 31, 2020 (issued as U.S. Pat. No. D903,064 on Nov. 24, 2020), the contents of each of which are incorporated herein by reference. U.S. patent application Ser. No. 17/834,417 filed on Jun. 7, 2022 is also a bypass continuation-in-part of International Application No. PCT/EP2021/079019 filed Oct. 20, 2021, which claims priority to U.S. Provisional Application 63/093,883 filed Oct. 20, 2020, the contents of each of which are incorporated herein by reference. U.S. patent application Ser. No. 17/834,417 filed on Jun. 7, 2022 is also a continuation-in-part of U.S. Design application Ser. No. 29/784,384 filed May 19, 2021, which is a continuation of U.S. Design application Ser. No. 29/781,925 filed May 3, 2021 (issued as U.S. Pat. No. D935,574 on Nov. 9, 2021), which is a continuation of U.S. Design application Ser. No. 29/755,354 filed Oct. 20, 2020 (issued as U.S. Pat. No. D921,858 on Jun. 8, 2021), which is a continuation-in-part of U.S. application Ser. No. 16/511,495 filed Jul. 15, 2019 (issued as U.S. Pat. No. 10,920,543 on Feb. 16, 2021), which is a continuation of U.S. application Ser. No. 16/272,326 filed Feb. 11, 2019 (issued as U.S. Pat. No. 10,458,213 on Oct. 29, 2019), which claims priority to U.S. Provisional Application No. 62/780,427 filed Dec. 17, 2018 and U.S. Provisional Application No. 62/699,484 filed Jul. 17, 2018, the contents of each of which are incorporated herein by reference.

Hydrocarbons, such as fossil fuels and natural gas, are extracted from underground wellbores extending deeply below the surface using complex machinery and explosive devices. Once the wellbore is established by placement of cases after drilling, a perforating gun assembly, or train or string of multiple perforating gun assemblies, is lowered into the wellbore and positioned adjacent one or more hydrocarbon reservoirs in underground formations. The perforating gun may have explosive charges which are ignited to create holes in the casing and to blast through the formation so that the hydrocarbons can flow through the casing. Once the perforating gun(s) is properly positioned, a surface signal actuates an ignition of a fuse, which in turn initiates a detonating cord, which detonates the shaped charges to penetrate/perforate the casing and thereby allow formation fluids to flow through the perforations thus formed and into a production string. The surface signal may travel from the surface along electrical wires that run from the surface to one or more initiators, such as ignitors or detonators positioned within the perforating gun assembly.

Assembly of a perforating gun requires assembly of multiple parts, which may include at least the following components: a housing or outer gun barrel within which is positioned an electrical wire for communicating from the surface to initiate ignition, of an initiator and/or a detonator, a detonating cord, one or more charges and, where necessary, one or more boosters. Assembly may include threaded insertion of one component into another by screwing or twisting the components into place, optionally by use of a tandem adapter. Since the electrical wire must extend through much of the perforating gun assembly, the wire may become easily twisted and crimped during assembly. In addition, when a wired detonator is used it must be manually connected to the electrical wire, which may lead to multiple problems. Due to the rotating assembly of parts, the wires can become torn, twisted and/or crimped/nicked, the wires may be inadvertently disconnected, or even mis-connected in error during assembly. This may lead to costly delays in extracting the hydrocarbons. Additionally, there is a significant safety risk associated with physically and manually wiring live explosives.

Accordingly, there may be a need for an initiator that would allow for reliable detonation of perforating guns without requiring physically and manually wiring live explosives.

Additionally, in certain applications, hydraulic fracturing may produce optimal results when perforations are oriented in the direction of maximum principle stress or the preferred fracture plane (PFP). Perforations oriented in the direction of the PFP create stable perforation tunnels and transverse fractures (perpendicular to the wellbore) that begin at the wellbore face and extend far into the formation. However, if fractures are not oriented in the direction of maximum stress, tortuous, non-transverse fractures may result, creating a complex near-wellbore flow path that can affect the connectivity of the fracture network, increase the chance of premature screen-out, and impede hydrocarbon flow. Accordingly, there may be a need for equipment that can allow for orientation verification of the perforating guns to ensure that perforations are formed in the preferred fracture plane. Similarly, there may be a need for perforating guns that can be efficiently connected together and the perforating direction individually oriented relative to other guns in a string.

In an aspect, the disclosure relates to an orientable perforating gun assembly, comprising a gun housing, a charge carrier, and an orientation alignment ring. The gun housing may have a first end and a second end opposite the first end, and an interior space between the first end and the second end. The charge carrier may be positioned in the gun housing interior space, in a fixed orientation relative to the gun housing, and the charge carrier may include a first end nearest to the gun housing first end, and a second end opposite the first end and nearest to the gun housing second end. The orientation alignment ring may be connected to the gun housing first end. The orientation alignment ring and the gun housing may be rotatable relative to each other when the orientation alignment ring is in an unfixed connection state, and an orientation of the gun housing may be fixed relative to the orientation alignment ring when the orientation alignment ring is in a fixed connection state.

In another aspect, the disclosure relates to an orientable perforating gun assembly, comprising a gun housing, a charge carrier, an initiator assembly, and an orientation alignment ring. The gun housing may include a first end and a second end opposite the first end, and an interior space between the first end and the second end. The charge carrier may be positioned in the gun housing interior space, in a fixed orientation relative to the gun housing, and the charge carrier may include a first end nearest to the gun housing first end, and a second end opposite the first end and nearest to the gun housing second end. The initiator assembly may be positioned within an initiator holder, in a fixed orientation relative to the charge carrier, at the charge carrier second end. The initiator assembly may include an orientation sensor, and the initiator holder and the initiator assembly may together be configured for the initiator assembly to initiate at least one of a detonating cord and a shaped charge within the gun housing interior space. The orientation alignment ring may be connected to the gun housing first end. The orientation alignment ring and the gun housing may be rotatable relative to each other when the orientation alignment ring is in an unfixed connection state, and an orientation of the gun housing may be fixed relative to the orientation alignment ring when the orientation alignment ring is in a fixed connection state.

In another aspect, the disclosure relates to a method for orienting an individual perforating gun assembly relative to other perforating gun assemblies in a string. The method may comprise providing the perforating gun assembly including a gun housing including a first end and a second end opposite the first end, and an interior space between the first end and the second end, a charge carrier positioned in the gun housing interior space, and retaining a shaped charge, in a fixed orientation relative to the gun housing, and an orientation alignment ring connected to the gun housing first end in an unfixed connection state. The method may further include rotating the gun housing to a desired orientation relative to the orientation alignment ring and fixing the orientation alignment ring to the gun housing first end by engaging a locking structure between the orientation alignment ring and the gun housing first end. The method may also include inserting an initiator assembly including an orientation sensor into an initiator holder on the charge carrier. In addition, the method may include connecting the perforating gun assembly to an adjacent, upstream perforating gun assembly, by connecting the gun housing second end to an orientation alignment ring of the adjacent, upstream perforating gun assembly.

Various features, aspects, and advantages of the exemplary embodiments will become more apparent from the following detailed description, along with the accompanying drawings in which like numerals represent like components throughout the figures and detailed description. The various described features are not necessarily drawn to scale in the drawings but are drawn to emphasize specific features relevant to some embodiments.

The headings used herein are for organizational purposes only and are not meant to limit the scope of the disclosure or the claims. To facilitate understanding, reference numerals have been used, where possible, to designate like elements common to the figures.

Reference will now be made in detail to various embodiments. Each example is provided by way of explanation and is not meant as a limitation and does not constitute a definition of all possible embodiments.

show an exemplary embodiment of an initiator head. The initiator head may include a housing, a circuit board, a line-in terminal, a line-out terminal, a ground terminal, a stem, and a fuse.

As seen in, the housingmay extend in an axial directionand may define an interior space. The housingmay be formed of an insulating material, and may be formed by molding,D-printing, additive manufacturing, subtractive manufacturing, or any other suitable method. For example, in an exemplary embodiment, the housingmay be formed of a non-conductive plastic material such as polyamide. The housingmay include a first housing pieceand a second housing pieceengaged together. Alternatively, the housingmay be an integral or monolithic piece molded or additively manufactured around the circuit board.

further shows that an exemplary embodiment of the first housing piecemay include a first plate. A thickness direction of the first platemay be substantially parallel to the axial direction. As further seen in, an exemplary embodiment of the first platemay be shaped as an annulus having a substantially circular periphery and a substantially circular through hole. The through holemay be structured to expose the line-in terminalto an exteriorof the housing. The first platemay further include a sloped wallsloping from the first plate in the axial directiontoward the circuit board. The sloped wallmay help to guide a contact pin to contact with the line-in terminal. The first housing piecemay further include a first outer peripheral wallextending from the first platein the axial direction.andshow an exemplary embodiment in which the first outer peripheral wallextends from an outer periphery of the first plate.

further shows that an exemplary embodiment of the second housing piecemay include a second plate. A thickness direction of the second platemay be substantially parallel to the axial direction. As further seen in, an exemplary embodiment of the second platemay be substantially circular in shape. The second platemay further include through holesstructured to expose the line-out terminaland the ground terminalto an exteriorof the housing. The second housing piecemay further include a second outer peripheral wallextending from the second platein the axial direction.andshow an exemplary embodiment in which the second outer peripheral wallextends from an outer periphery of the second plate.

As further seen in, the first outer peripheral walland the second outer peripheral wallmay overlap in the axial direction, such that the interior spaceis formed between the first plateand the second platein the axial direction. In other words, the interior spacemay be bounded by the first housing pieceand the second housing piece. In an exemplary embodiment, a first housing piece radius of the first housing piecemay be smaller than a second housing piece radius of the second housing piece. Thus, the first housing piecemay be received within the second housing piecewith the first outer peripheral wallbeing provided between the first plateand the second platein the axial direction. Alternatively, the first housing piece radius may be larger than the second housing piece radius, and the second housing piecemay be received within the first housing piece, with the second peripheral wallbeing provided between the first plateand the second platein the axial direction.

The first housing pieceand the second housing piecemay be dimensioned such that the first housing pieceand the second housing piecefit snugly together so as not to separate under normal operating conditions. Alternatively, the first housing pieceand the second housing piecemay be provided with a coupling mechanism such as hook or protrusion and a complementary recess, so that the first housing pieceand the second housing piecemay snap together. Alternatively, the first outer peripheral walland the second outer peripheral wallmay be complementarily threaded so that the first housing pieceand the second housing piecemay screw together. Alternatively, the first housing pieceand the second housing piecemay be bonded together with adhesive.

further shows an exemplary embodiment of a circuit board. A thickness directionof the circuit boardmay be substantially parallel with the axial direction. As explained in further detail herein, orienting the thickness directionsubstantially parallel with the axial directionallows room for larger firing capacitors and/or surface mounted componentsto be mounted on the circuit board.

In an exemplary embodiment, the line-in terminal, the line-out terminal, the ground terminal, and the fusemay be in electrical communication with the circuit board. The line-in terminalmay be provided on a first side of the circuit boardin the axial direction, and thereby the line-in terminalmay be provided on a first side of the housingin the axial direction (i.e., to the left in). The line-out terminaland the ground terminalmay be provided on a second side of the circuit boardin the axial direction opposite to the first side (i.e., to the right in). The line-out terminalmay be configured to output a signal received by the line-in terminal, either directly or in response to processing by the circuit board, as described in detail herein, by being in electrical communication with either the line-in terminalor the circuit board.

shows an exemplary embodiment in which a plurality of line-out terminalsand a plurality of ground terminalsare provided. The plurality of line-out terminalsand the plurality of ground terminalsprovide a layer of redundancy to help ensure sufficient connection of the initiator headto external electrical components, as explained in detail herein. Each line-out terminalof the plurality of line-out terminalsmay be directly connected to each other within the housingor on the circuit board. In other words, if one line-out terminalis in electrical communication with the circuit board, then each line-out terminalof the plurality of line-out terminalsmay be in electrical communication with the circuit board. Similarly, if one line-out terminalbecomes in electrical communication with the line-in terminal, then each line-out terminalof the plurality of line-out terminals may be in electrical communication with the line-in terminal. Similarly, if one ground terminalis in electrical communication with the circuit board, then each ground terminalof the plurality of ground terminalsmay be in electrical communication with the circuit board.

As further seen inand, the circuit boardmay be a printed circuit board and/or may include one or more surface mounted components. The arrangement of the circuit boardand the shape of the initiator headmay provide sufficient space in the interior spaceto accommodate a variety of surface mounted components. In an exemplary embodiment, the surface mounted componentof the circuit boardmay be an integrated circuit (IC) with a dedicated function, a programmable IC, or a microprocessor IC. The circuit boardmay be configured to activate the fusein response to a control signal received at the line-in terminal. For example, a user may send a firing signal via a firing panel. The firing signal may be received at the line-in terminal, and the circuit board, through ICs provided on the circuit board, may process the firing signal and activate the fuse. Additionally, the circuit boardmay include a switch circuit configured to establish electrical communication between the line-out terminaland the line-in terminalin response to a predetermined switch signal. The line-out terminalmay be in electrical communication with subsequent initiator headsprovided downstream in a string of connected perforating guns, thereby allowing a user to send switch signals to toggle which initiator head is active to receive a firing command.

In an exemplary embodiment, one of the surface mounted componentsmay be one selected from a group consisting of a temperature sensor, an orientation sensor, a safety circuit, and a capacitor. Readings from one of these components may be used by a microprocessor on circuit boardto determine when it is appropriate to activate the fuse. The temperature sensor may be configured to measure temperature of the wellbore environment and provide a signal corresponding to the temperature to the circuit board. The orientation sensor may include, but is not limited to, an accelerometer, a gyroscope, and/or a magnetometer. The orientation sensor may be configured to determine an orientation of the initiator headwithin the wellbore, which, if the orientation of the initiator head is fixed relative to a charge holder, can be used to determine an orientation of the charge(s) in the perforating gun. In an exemplary embodiment, the orientation sensor may determine an orientation of the initiator headrelative to gravity. Alternatively, the orientation sensor may determine an orientation of the initiator head relative an ambient magnetic field. The safety circuit may provide additional safety precautions to prevent unintentional activation of the initiator. The capacitor may be used to store a voltage to activate the fuse. The size of the interior spacemay allow for a larger capacity capacitor to be used. This allows a larger discharge voltage for activating the fuse, which may help to ensure more reliable activation of the fuse.

andfurther show an exemplary embodiment of the stem. The stemmay extend in the axial directionfrom the housing. In an exemplary embodiment, the stemmay be formed of the same material as the second housing pieceand may be integrally and/or monolithically formed with the second plate. Alternatively, the stem may be formed as a separate piece and mechanically connected to the second housing piece via clips or mated structures such as protrusions and recesses, or adhesively connected using an adhesive.

As seen in, the stemmay include a stem outer peripheral wall. The stem outer peripheral wallmay define a stem cavityprovided radially inward from the stem outer peripheral wall. A first discharge channeland a second discharge channelmay connect the stem cavityand the interior spaceof the housing. The first discharge channelmay accommodate therein a first discharge terminalin electrical communication with the circuit board. In other words, the first discharge terminalmay extend from the circuit boardinto the first discharge channel. Similarly, the second discharge channelmay accommodate therein a second discharge terminalin electrical communication with the circuit board. In other words, the second discharge terminalmay extend from the circuit boardinto the second discharge channel.

further shows that, in an exemplary embodiment, the fusemay be provided within the stem cavity. A first end of a first fuse terminalmay be in electrical communication with the first discharge terminalwithin the first discharge channel, and a second end of the first fuse terminal may be proximate to the fuse. A first end of a second fuse terminalmay be in electrical communication with the second discharge terminalwithin the second discharge channel, and a second end of the second fuse terminalmay be proximate to the fuseand the second end of the first fuse terminal. The circuit boardmay be configured to activate the fusein response to a control signal by discharging a stored voltage across the first fuse terminaland the second fuse terminal. The store voltage may be stored in a capacitor in electrical communication with the circuit board. In an exemplary embodiment, the capacitor may be one of the surface mounted componentsprovided on the circuit board. The proximity of the second end of the first fuse terminaland the second end of the second fuse terminalmay allow for the generation of a spark when the stored voltage is discharged, thereby activating the fuse. In an exemplary embodiment, activating the fusemay include igniting or detonating the fuse.

As seen in, an exemplary embodiment of the stemmay include a windowcut through the stem outer peripheral wall. The windowmay allow access for a user to connect the first discharge terminalto the first fuse terminaland the second discharge terminalto the second fuse terminal, such as by soldering, during assembly of the initiator head.

show exemplary embodiments in which the circuit boardis in electrical communication with the fusevia direct physical contact, so as to streamline the manufacturing process by eliminating soldering between the circuit boardand the fuse. For example,shows an exemplary embodiment in which the circuit boardis in electrical communication with the fusevia a fuse connector assembly. The fuse connector assemblymay include a first discharge connectorconfigured to receive and make direct electrical contact with the first fuse terminaland a second discharge connectorconfigured to receive and make direct electrical contact with the second fuse terminal(not shown in).

The fuse connector assemblymay include a mounting block, the first discharge connectorextending through the mounting block, and the second discharge connectorextending through the mounting block. The mounting blockmay be formed of an insulating material and may facilitate connection and/or fastening of the fuse connector assemblyto the circuit board. Further, the mounting blockmay provide mechanical strength and support for the fuse connector assembly. When the fuse connector assemblyis connected to the circuit board, the first discharge connectorand the second discharge connectormay extend from the circuit boardinto the stem.

further shows an exemplary embodiment of the first discharge connector. For simplicity, only the first discharge connectoris described in detail herein; it will be understood fromthat the second discharge connectormay be substantially similar to the first discharge connectorin terms of structure. The first discharge connectormay be formed of an electrically conductive material. The first discharge connectormay include a first body portion, and a first board connector terminalmay be provided at a first end of the first body portion. The first board connector terminalmay connect to the circuit board.

The first discharge connectormay further include a first base portionand a second base portionextending from the first body portionat a second end of the first body portion. The first discharge connectormay further include a first arm portionextending from the first base portionand a second arm portionextending from the second base portion. The first arm portionmay be bent or inclined in a direction toward the second arm portion. Similarly, the second arm portionmay be bent or inclined in a direction toward the first arm portion. The first discharge connectormay further include a first tip portionat an end of the first arm portionand a second tip portionat an end of the second arm portion. The first tip portionmay be bent or inclined in a direction away from the second tip portion. Similarly, the second tip portionmay be bent or inclined in a direction away from the first tip portion.

A first contact portionmay be formed between the first arm portionand the first tip portion, and a second contact portionmay be formed between the second arm portionand the second tip portion. The first contact portionmay be resiliently biased toward the second contact portionbased on the connection between the first base portionand the first arm portion. Similarly, the second contact portionmay be resiliently biased toward the first contact portionbased on the connection between the second base portionand the second arm portion. The first contact portionmay be in contact with the second contact portion. Alternatively, there may be a gap between the first contact portionand the second contact portion. In an exemplary embodiment, a size of the gap may be less than a thickness of the first fuse terminal.

The first discharge connectormay be configured to receive, and make electrical contact with, the first fuse terminal. Similarly, the second discharge connectormay be configured to receive, and make electrical contact with, the second fuse terminal. For example, during assembly of the initiator head, the circuit boardand the fusemay be pushed together in the axial direction, thereby bringing the first fuse terminalinto contact with the first tip portionand the second tip portion. Further relative motion between the fuseand the circuit boardmay cause the first fuse terminalto deflect the first tip portionand the second tip portionaway from each other. The first fuse terminalmay then be in contact with the first contact portionand the second contact portion, i.e., sandwiched between the first contact portionand the second contact portion. The resilient bias of the first contact portionand the second contact portionmay help to maintain contact, and thus electrical communication, between the first contact portion, the second contact portion, and the first fuse terminal. It will be understood that contact between the second discharge connectorand the second fuse terminalmay be achieved in a similar way. The windowmay allow for visual confirmation of the connection between the first discharge connectorand the first fuse terminaland between the second discharge connectorand the second fuse terminal.

shows an exemplary embodiment in which the circuit boardis in electrical communication with the fusevia a fuse connector assembly. The fuse connector assemblymay include a first discharge connectorconfigured to receive and make direct electrical contact with the first fuse terminaland a second discharge connectorconfigured to receive and make direct electrical contact with the second fuse terminal(not shown in).

The fuse connector assemblymay include a mounting block, the first discharge connectorextending through the mounting block, and the second discharge connectorextending through the mounting block. The mounting blockmay be formed of an insulating material and may facilitate connection and/or fastening of the fuse connector assemblyto the circuit board. Further, the mounting blockmay provide mechanical strength and support for the fuse connector assembly. When the fuse connector assemblyis connected to the circuit board, the first discharge connectorand the second discharge connectormay extend from the circuit boardinto the stem.

further shows an exemplary embodiment of the first discharge connector. For simplicity, only the first discharge connectoris described in detail herein; it will be understood fromthat the second discharge connectormay be substantially similar to the first discharge connectorin terms of structure. The first discharge connectormay be formed of an electrically conductive material. The first discharge connectormay include a first body portion, and a first board connector terminalmay be provided at a first end of the first body portion. The first board connector terminalmay connect to the circuit board.

The first discharge connectormay further include a first base portionand a second base portionextending from the first body portionat a second end of the first body portion. The first discharge connectormay further include a first arm portionextending from the first base portionand a second arm portionextending from the second base portion. The first arm portionmay be bent or inclined in a direction away from the second arm portion. Similarly, the second arm portionmay be bent or inclined in a direction away from the first arm portion. The first discharge connectormay further include a first tip portionat an end of the first arm portionand a second tip portionat an end of the second arm portion. The first tip portionmay be bent or inclined in a direction toward the second tip portionand back toward the first body portion. Similarly, the second tip portionmay be bent or inclined in a direction toward the first tip portionand back toward the first body portion.

A first contact portionmay be formed at an end of the first tip portion, and a second contact portionmay be formed at an end of the second tip portion. The first contact portionmay be resiliently biased toward the second contact portionbased on the connection between the first base portionand the first arm portion. Similarly, the second contact portionmay be resiliently biased toward the first contact portionbased on the connection between the second base portionand the second arm portion. The first contact portionmay be in contact with the second contact portion. Alternatively, there may be a gap between the first contact portionand the second contact portion. In an exemplary embodiment, a size of the gap may be less than a thickness of the first fuse terminal.

The first discharge connectormay be configured to receive, and make electrical contact with, the first fuse terminal. Similarly, the second discharge connectormay be configured to receive, and make electrical contact with, the second fuse terminal. For example, during assembly of the initiator head, the circuit boardand the fusemay be pushed together in the axial direction, thereby bringing the first fuse terminalinto contact with the first tip portionand the second tip portion. Further relative motion between the fuseand the circuit boardmay cause the first fuse terminalto deflect the first tip portionand the second tip portionaway from each other. The first fuse terminalmay then be in contact with the first contact portionand the second contact portion, i.e., sandwiched between the first contact portionand the second contact portion. The resilient bias of the first contact portionand the second contact portionmay help to maintain contact, and thus electrical communication, between the first contact portion, the second contact portion, and the first fuse terminal. It will be understood that contact between the second discharge connectorand the second fuse terminalmay be achieved in a similar way. The windowmay allow for visual confirmation of the connection between the first discharge connectorand the first fuse terminaland between the second discharge connectorand the second fuse terminal.

show an exemplary embodiment in which the circuit boardis in electrical communication with the fusevia a fuse connector assembly. The fuse connector assemblyis similar in many aspects to the fuse connector assembly; similar structures will be indicated with the same reference numerals, and detailed descriptions of these similar structures will be omitted. In the fuse connector assembly, the first arm portionmay include a first arm partextending from the first base portionand a second arm partextending from the first arm part. The second arm portionmay include a third arm partextending from the first base portionand a fourth arm partextending from the first arm part. Each of the first art partand the third arm partmay be bent or inclined in a direction away from each other. Each of the second arm partand the fourth arm partmay be bent or inclined in a direction toward each other.

shows an exemplary embodiment of an initiator. The initiatormay include an initiator headand an initiator shell. The initiator headmay be similar in structure and function as described in detail above. The initiator shellmay be coaxial with the initiator head. In an exemplary embodiment, a head dimension Xof the headin a first direction perpendicular to the axial directionmay be larger than a shell dimension Xin the first direction. According to an aspect, the initiator may be configured as an ignitor or a detonator, depending on the needs of the application.

In an exemplary embodiment, the initiator shellmay include a shell walland a shell crimpcrimped around the stem. The shell wallmay extend in the axial directionand may be formed of a deep-drawn metal. Non-limiting examples of the metal used for the shell wallmay include aluminum, copper, steel, tin, or brass. Plastics may also be used a material for the shell wall. The shell wallmay define a shell interior. A primary explosivemay be provided within the shell interior. In an exemplary embodiment, the circuit boardmay be configured to activate the primary explosive, and in some embodiments the primary explosiveand the secondary explosive, in response to a control signal received at the line-in terminal. For example, the primary explosivemay be arranged such that the fuseis within an operable distance of the primary explosive. Being within an operable distance means that the fuseis provided close enough to the primary explosivethat the primary explosiveis ignited and/or detonated when the fuseis activated. In other words, by activating the fusein response to a control signal, the circuit boardmay activate the primary explosive.

The secondary explosivemay abut the primary explosiveand seal the primary explosivewithin a non-mass explosive (NME) body. The primary explosiveand the secondary explosivemay have a total thickness of about 3 mm to about 30 mm in an exemplary embodiment. Alternatively, the total thickness may be about 3 mm to about 10 mm. The secondary explosivemay be configured as a layer of an explosive material. According to an exemplary embodiment, the primary explosivemay include at least one of lead azide, silver azide, lead styphnate, tetracene, nitrocellulose, BAX, and a lead azide free primary explosive as described in USPGP 2019/0256438, herein incorporated by reference.

Each of the primary explosiveand the secondary explosivemay have a safe temperature rating of above 150° C. (with the exception of PETN, which has a rating of approximately 120° C.). The secondary explosivemay include a material that is less sensitive to initiation, as compared to the primary explosive. The secondary explosivemay include at least one of PETN, RDX, HMX, HNS and PYX. In an embodiment, the secondary explosivemay be less sensitive to initiation than PETN.

The primary explosiveand the secondary explosivemay be provided within the NME body. The NME bodymay help to avoid an unintentional initiation of the primary explosiveor the main load explosiveby an external mechanical force. The NME bodymay be composed of an electrically conductive, electrically dissipative or electrostatic discharge (ESD) safe synthetic material. According to an exemplary embodiment, the non-mass-explosive bodymay be formed of a metal, such as cast-iron, zinc, machinable steel or aluminum. Alternatively, the NME bodymay be formed from a plastic material. While the NME bodymay be made using various processes, the selected process utilized for making the NME bodyis based, at least in part, by the type of material from which it is made. For instance, when the NME bodyis made from a plastic material, the selected process may include an injection molding process. When the NME bodyis made from a metallic material, the NME bodymay be formed using any conventional CNC machining or metal casting processes.

The initiator shellmay further include a main load explosiveprovided adjacent the primary explosive, and in embodiment including a secondary explosive, adjacent the secondary explosive. The main load explosiveincludes compressed secondary explosive materials. According to an aspect, the main load explosivemay include one or more of cyclotrimethylenetrinitramine (RDX), octogen/cyclotetramethylenetetranitramine (HMX), hexanitrostilbene (HNS), pentaerythritol tetranitrate (PETN), 2,6-Bis(picrylamino)-3,5-dinitropyridine (PYX), and 1,3,5-triaminio-2,4,6-trinitobenzene (TATB). The type of explosive material used may be based at least in part on the operational conditions in the wellbore and the temperature downhole to which the explosive may be exposed.

In an exemplary embodiment shown in, an exterior shape of the housingmay be rotationally asymmetric with respect to the axial direction. In other words, when looking along the axial direction, a periphery of the housingmay be shaped such that an orientation of the housingis unique for each angle around the axial direction. For example,shows that a key protrusionor a key protrusionmay be formed on a periphery of the housing, andshows that a key recessmay be formed on a periphery of the housing. As is clear fromand, there are no possible rotations of the housingwhere the housinghas a matching profile. In other words, an exterior profile of housingis unique for each possible rotation angle. It will be understood that the size, shape, and/or number of key protrusions and/or key recesses is not limited to what is shown inand, as long as they create a rotational asymmetry in the shape of housing. Additionally, key protrusions and key recesses may be combined together on a single housing.

illustrate an exemplary embodiments of an initiator system. The initiator systemmay include an initiator holder(see) and an initiatorreceived within the initiator holder.

As seen in, an exemplary embodiment of the initiator holdermay include a holder ground terminal. The holder ground terminalmay include a holder ground contact. In an exemplary embodiment shown in, the holder ground contactmay be punched from the material of the holder ground terminaland then bent to a side of the holder ground terminal. This may help to impart a spring-loaded action to the holder ground contactand bias the holder ground contactin a direction toward the initiator head, thereby helping to ensure a more secure electrical contact between the ground terminaland the holder ground contact. In other words, when the initiatoris positioned within the initiator holder, the holder ground contactmay be in electrical communication with the ground terminal(see) via contact.

, andshow that, in an exemplary embodiment of the holder ground terminal, the holder ground contactmay be one of a plurality of holder ground contacts. As seen in, if the initiator headincludes a plurality of ground terminals, then the plurality of holder ground contactsprovided a layer of redundancy for establishing a connection to ground. For example, even of one pair the ground terminalsand the holder ground contactsfails to establish a secure electrical connection, a second pair of the ground terminalsand the holder ground contactsmay form a secure electrical connection.

As further seen in, the initiator holdermay further include a holder ground barextending from the holder ground terminal. The holder ground barmay contact a ground when the initiator holderis received within a perforating gun. In other words, the holder ground terminalmay be in electrical communication with ground, for example through the holder ground bar.