Patent ID: 12235086

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.

DETAILED DESCRIPTION

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.

For purposes of this disclosure, a “drone” is a self-contained, autonomous or semi-autonomous vehicle for downhole delivery of a wellbore tool. For purposes of this disclosure and without limitation, “autonomous” means without a physical connection or manual control and “semi-autonomous” means without a physical connection. An “autonomous perforating drone” according to some embodiments is a drone in which, e.g., shaped charges carried by the drone are detonated within the wellbore; however, as the disclosure makes clear, an “autonomous perforating drone” is not limited to a drone for downhole delivery of shaped charges and may include any known or later-developed wellbore tools consistent with this disclosure. Further, the use of the word “drone” throughout this disclosure may be used interchangeably and/or for brevity with the phrase “autonomous perforating drone” without limitation, except where the specification otherwise makes clear.

Embodiments of the disclosure are associated with an initiator configured to focus a ballistic output in a longitudinal direction away from the initiator's body. The initiator may be configured as an ignitor or a detonator.

FIGS.1-6andFIGS.8-15illustrate embodiments of the initiator when configured as a detonator/focused output detonator100. The focused output detonator100focuses a ballistic output in a longitudinal direction, away from the focused output detonator100.

As illustrated inFIG.1, the focused output detonator100includes a detonator shell200. The detonator shell200may be configured as a housing or casing, typically a metallic housing. The detonator shell200may be shaped as a hollow cylinder having a body210extending along a central axis Y of the detonator shell200. A first open end212is provided at a first end of the body210, and a closed end214is provided at a second end of the body210. The detonator shell200includes a chamber/hollow interior216extending between the first open end212and the closed send214. The chamber216is bounded by the body210and the closed end214and is configured to receive detonator components (described in further detail hereinbelow). A focusing assembly300(described in further detail hereinbelow), such as a shaped charge301, may be secured to the closed end214.

FIGS.2-3andFIGS.4-6illustrate the focused output detonator100in more detail. The detonator shell200of the focused output detonator100includes a main explosive load220disposed within the chamber216of the detonator shell200. The main explosive load220may be positioned such that it is adjacent the closed end214of the detonator shell200and spaced a distance away from the first open end212. The main explosive load220may include a compressed secondary explosive material. According to an aspect, the main explosive load220includes one or more of cyclotrimethylenetrinitramine (RDX), octogen/cyclotetramethylenetetranitramine (HMX), hexanitrostilbene (HNS), pentaerythritol tetranitrate (PETN), and 2,6-Bis(picrylamino)-3,5-dinitropyridine (PYX). It is contemplated that the main explosive load220may include a plurality of explosive materials that are mixed together and compressed. The type of explosive material/(s) used in the main explosive load220may be based at least in part on the operational conditions in the wellbore and the temperature downhole to which the focused output detonator100may be exposed.

A non-mass explosive (NME) body400is disposed within the chamber216adjacent to or on top of the main explosive load220. The NME body may sandwich the main explosive load220between the closed end214of the detonator shell200and the NME body400. According to an aspect, the NME body400is sized so that it is frictionally retained within the chamber216and encases or encloses the main explosive load220within the chamber216. The NME body400may include a head portion410and a leg portion420opposite the head portion. The head portion410is adjacent the main explosive load220, while the leg portion420extends in a direction away from the head portion410, towards the first open end212of the body210of the detonator shell200. Explosives may be positioned in the head portion410.

According to an aspect and as illustrated inFIG.4, a primary explosive412is embedded within the head portion410, and a secondary explosive414is positioned such that it is in contact with or abutting the primary explosive412. The secondary explosive414may be configured to seal the primary explosive412within the head portion410. One or more channels430are formed between the head portion410and the leg portion420and may be in fluid communication with each other. The channels430are arranged such that, in the event that fluid enters the focused output detonator100, the fluid will fill the channels and serve as a barrier that prevents activation of the focused output detonator100.

The NME body400is configured to prevent a mass explosion (full explosion at one time) in a package of focused output detonators100in the event that there is, for example, a fire while the package is being stored or if one focused output detonator100is accidently initiated. The NME body400is also configured to protect the primary explosive from mechanical impact or unwanted friction. The NME body400is composed of an electrically conductive, electrically dissipative or electrostatic discharge (ESD) safe synthetic material. According to an aspect, the NME body400includes a metal, such as cast-iron, zinc, machinable steel or aluminum. Alternatively, the NME body400may be formed from a plastic material. While the NME body400may be made using various processes, the selected process utilized for making the NME body400is based, at least in part, by the type of material from which it is made. For instance, when the NME body400is made from a plastic material, the selected process may include an injection molding process. When the NME body400is made from a metallic material, the NME body400may be formed using any computer numerical control (CNC) machining or metal casting processes. The NME body400is configured for use with the focused detonator100and may be configured substantially as the NME body described and shown in U.S. Pat. No. 10,400,558, which is commonly-owned and assigned to DynaEnergetics GmbH & Co. KG and incorporated herein by reference in its entirety to the extent that it is consistent with this disclosure.

While initiation mechanisms for detonators may include an exploding bridge wire (EBW) or an exploding foil initiator (EFI), the focused output detonator100may include an alternative initiation mechanism. According to an aspect, the focused output detonator100does not include EBW or EFI. Alternatively, the initiation mechanism of the focused output detonator100includes a fuse. As further seen inFIG.2, the focused output detonator100further includes an electronic circuit board or printed circuit board230connected to a fuse/fuse head240. The electronic circuit board230and the fuse240are housed within the chamber216. According to an aspect, the fuse240is disposed within the chamber216so it is adjacent the NME body400, while the electronic circuit board230extends between the fuse240and the open end212of the detonator shell210. The electronic circuit board230, in combination with the fuse240, facilitates detonation of the focused output detonator100. The All Fire current for the fuse head240may be about 450 milliAmps. When the focused output detonator100is to be initiated or fired, a signal of about 450 milliAmps, or above, is sent to the fuse head240so that the focused output detonator100is initiated or fired. The focused output detonator10may fire at a certainty level of about 99.98% upon receipt of the required All File current. According to an aspect, the No Fire current for the fuse head240is less than about 150 milliAmps. This allows a user to be able to test the focused output detonator (i.e., test the various sensors, described in further detail hereinbelow, or the electronic circuit board of the focused output detonator100) without initiating or firing the focused output detonator100. The electronic circuit board230may include one or more surface mounted components. In an exemplary embodiment, the surface mounted component of the electronic circuit board230may be an integrated circuit (IC) with a dedicated function, a programmable IC, or a microprocessor IC. The electronic circuit board230may be configured to activate the fuse240in response to a control signal received from a wire or a line-in terminal (described in further detail hereinbelow). For example, a user may send a firing signal via a firing panel. The firing signal may be received at the wire or line-in terminal, and the electronic circuit board230, through ICs provided on the electronic circuit board230, may process the firing signal and activate the fuse240. Additionally, the electronic circuit board230may include a switch circuit configured to operably connect a line-out terminal (described in further detail hereinbelow) to the line-in terminal in response to a predetermined switch signal. The electronic circuit board230ensures that the focused output detonator100is immune to electromagnetic radiation (EMC), is RF-Safe and intrinsically safe and is also safe in regard to ESD (electro-static discharge). According to an aspect, the focused output detonator100includes a temperature sensor. The temperature sensor may be configured to measure temperature of the wellbore environment and provide a signal corresponding to the temperature to the electronic circuit board230. The focused output detonator may include an orientation sensor. The orientation sensor may include, but is not limited to, an accelerometer, a gyroscope, a tilt sensor, a motion sensor and/or a magnetometer. The orientation sensor may be configured to determine an orientation of the focused output detonator100within the wellbore. In an exemplary embodiment, the orientation sensor may determine an orientation of the focused output detonator100relative to gravity. Alternatively, the orientation sensor may determine an orientation of the focused output detonator100relative an ambient magnetic field. The focused output detonator may include a radio frequency identification (RFID) sensor configured to track one or more objects in the wellbore. Such objects may include other focused output detonators100, one or more wellbore casing including casing markers, and/or casing collars. To be sure, the focused output detonator100may include additional sensors, as the needs of the application requires.

According to an aspect, and as illustrated inFIGS.2-3andFIGS.4-6, the focused output detonator100further includes a plug500that closes/seals the open end212of the detonator shell200from fluids or unwanted materials. The plug500may have be configured as a cylindrical structure that is configured for being at least partially disposed in the chamber of detonator shell200, adjacent the open end212. The plug500includes a main body515and a shoulder510extending from the main body515. As illustrated inFIGS.2-4, for example, the main body515extends into the chamber216and the shoulder510abuts against the first open end212of the body210of the detonator shell200.FIG.2illustrates the main body515having a maximum outer diameter ODMAX that is selected such that the main body515fits within the detonator shell, while the shoulder510may have an outer diameter OD1that is larger than the outer diameter of the main body515. The electronic circuit board230, the fuse240, the non-mass-explosive body400and the main explosive load220are all enclosed within the shell210, by virtue of the plug500closing the open end212.

According to an aspect and as illustrated inFIGS.2-6, a wire520extends through the plug500and is electrically connected to the electronic circuit board230. To be sure, it is contemplated that the focused output detonator100could be wired (FIGS.2-6) or wire-free (FIGS.8-15). The wire520may be configured to electrically connect the focused output detonator100to a control unit at a factory or assembly location or at the surface of the wellbore. The threshold values and other instructions for addressing, arming, and/or detonating the focused output detonator100may be taught to a programmable electronic circuit (that is, of the electronic circuit board230) by the control unit. An electrical selective sequence signal may be sent from, e.g., the programmable electronic circuit to the focused output detonator100to initiate the focused output detonator100when, for example, an autonomous perforating drone reaches at least one of a threshold pressure, temperature, horizontal orientation, inclination angle, depth, distance traveled, rotational speed, and position within the wellbore. While a single wire520is shown, the wire520may include an electrical line in wire that passed information from the control unit to the electronic circuit board230and a ground wire serving as a ground for the focused output detonator100. It is contemplated that the wire/(s)520may be replaced by pin or plate contacts, such that the connection between the control unit and the electronic circuit board230is made by physical contact (such as surface to surface) between one or more components of the electronic circuit board230and the pin or plate contacts.

According to an aspect, a coupler250extends along an external surface of the detonator shell200, at the closed end214. Alternatively, the coupler250may extend along an recessed area (not shown) of the closed end214of the body210of the detonator shell200. The coupler250may include a bayonet connector, an adhesive, crimp, wedge, weld, or snap-on type connectors. The coupler250may include a thread configured as one of a continuous thread or interrupted threads. As used herein, “continuous thread/(s)” may mean a non-interrupted threaded closure having a spiral design (e.g., extending around the skirt like a helix), while “interrupted thread/(s)” may mean a non-continuous/segmented thread pattern having gaps/discontinuities between each adjacent thread. The thread may facilitate connection of the detonator shell200with other mechanisms, as described in further detail hereinbelow.

According to an aspect, a focusing assembly/focuser300is secured to the closed end214of the body210of the detonator shell200. The detonator shell200and the focusing assembly300may be connected such that the focused output detonator100focuses a ballistic output of the focuser300along the central axis Y of the detonator shell200and away from the detonator shell.

The focusing assembly300may include a donor charge301secured to the closed end214of the detonator shell200and extending along the central axis Y of the detonator shell200. The donor charge301includes a case310having, among other things, a cavity/hollow interior312, an initiating end314, and a second open end316opposite and spaced apart from the initiating end314. The case310may include a plurality of walls including a back wall and a side wall extending from the back wall. The side and back wall together form the cavity312of the case310. The back and side walls of the case310may be arranged such that the donor charge301is a conical shaped donor charge, a linear shaped donor charge, or any other shape consistent with this disclosure. According to an aspect and as illustrated inFIGS.1-6, for example, the side walls of the case310may be configured such that at least a portion of the case310is substantially conical. The case310may be formed from machinable steel, aluminum, stainless-steel, copper, zinc, and the like.

According to an aspect, an explosive load320is disposed in the cavity312of the case310. It is contemplated that at least some of the explosive load320may be disposed within an initiation point315formed in the back wall of the donor charge301. The initiation point315is a thinned region or an opening at the initiating end314of the case, which facilitates ease of transmission of a shock wave to the explosive load320upon initiation of the focused output detonator100. The explosive load320is disposed in the cavity312of the case310such that the explosive load320is adjacent at least a portion of the internal surface of the case310, including the initiation point315. According to an aspect, the explosive load320includes at least one of pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine/cyclotetramethylene-tetranitramine (HMX), hexanitrostibane (HNS), diamino-3,5-dinitropyrazine-1-oxide (LLM-105), pycrlaminodinitropyridin (PYX) and triaminotrinitrobenzol (TATB).

The explosive load320may be positioned in the cavity312in increments, such that the explosive load320includes multiple layers. According to an aspect, the explosive load320includes a first layer disposed in the cavity212adjacent the initiating end214, and a second layer atop the first layer. The first layer may include a first explosive load, while the second layer includes a second explosive load. The first explosive load may be composed of pure explosive powders, while the second explosive load includes a binder. According to an aspect, at least a portion of a first explosive load may be disposed in a portion of the initiation point315.

A liner340may also be disposed in the cavity312of the case310, such that the liner340is in a covering relationship with the explosive load320. According to an aspect, liner340is composed of various constituents, such as powdered metallic and non-metallic materials, powdered metal alloys and binders. According to an aspect, the constituents of the liner340are compressed to form a desired liner shape including, without limitation, a conical shape as shown inFIGS.2-6, a hemispherical or bowl-shape, or a trumpet shape. When the donor charge301includes the aforementioned first and second explosive loads, the liner340may extend into the first explosive load. The explosive load (including, for example, the first and second layers of explosive load) may be positioned, within the cavity312of the case310, between the liner340and the internal surface of the case210and enclosed therein.

When the focused output detonator100is initiated, the main explosive load220initiates the explosive load320in the cavity312of the case310. A detonation wave (or initiation energy produced upon initiation of the focused output detonator100) travels to the initiation point315, and ultimately to the explosive load320of the donor charge301. The explosive load320detonates and creates a detonation wave, which generally causes the liner340to collapse and be ejected from the case310, thereby producing a forward moving perforating jet. This perforating jet may travel to a target, such as, for example, a ballistic interrupt prior to initiating another detonating device (ex: detonating cord, booster, or explosive pellets).

The initiating end314of the case310may be configured with a securing mechanism338. The securing mechanism338may be configured to secure the donor charge301to the closed end214of the detonator shell200. According to an aspect, the securing mechanism338includes one of more of one or more of a thread, a bayonet connector, an adhesive, crimp, wedge, weld, snap-on connector, and friction fit.

According to an aspect, the coupler250may be a first coupler250at the closed end214of the detonator shell200, which corresponds to the securing mechanism338of the donor charge301. According to an aspect, the first coupler250is structured to secure the focuser300to the detonator shell200. The first coupler250may include, without limitation, one or more of a thread, a bayonet connector, an adhesive, crimp, wedge, weld, snap-on connector, and friction fit.

The case310of the donor charge301may include a second coupler/fastening member330that fixedly secures the focusing assembly300to the detonator shell200. The fastening member330may be configured as a protrusion332that extends from the initiation end314in a direction away from the open end316of the case310. According to an aspect, the protrusion332includes a wall334and an opening336bounded by the wall334. The wall334may be circumferentially disposed about the closed end214of the detonator shell200. The wall334is illustrated inFIGS.2-6as including a thread formed on an inner surface of the wall334and extending in the Y direction of the detonator shell200. To connect the detonator shell200to the focusing assembly300, the closed end214of the detonator shell200may be received in the opening336of the protrusion334and secured thereto by the fastening member330. Alternatively, and according to an embodiment (not shown), the closed end214of the detonator shell200may be configured for receiving and fastening the protrusion332in a depression formed therein.

According to an aspect, and as illustrated inFIGS.4-6, the donor charge301may be configured as an encapsulated and hydraulically sealed donor charge302. In addition to the features and components of the donor charge301described hereinabove, the encapsulated and hydraulically sealed donor charge302may include a cap/encapsulation member350in a covering relationship with the open end316of the case310.

According to an aspect, the cap350is secured to the case310by at least one of a friction fit, crimp, rolling, tongue and groove and swage connection. One or more securing mechanisms may be provided to prevent the closure member350from being unintentionally dislodged from the case310. Such securing mechanisms may include grooves, click-rings, notches and the like. The securing mechanism may include a melting ring to mechanically fix the cap350to the case310and creates a mechanical seal between the case310and the cap350.

FIG.4andFIG.5illustrate the cap350having an outwardly domed surface or a convex surface that provides additional space within the encapsulated and hydraulically sealed donor charge302. It is contemplated that the outwardly domed surface of the closure member350may also help the encapsulated and hydraulically sealed donor charge302to withstand pressures in the wellbore. For example, the encapsulated and hydraulically sealed donor charge may be configured to withstand a hydrostatic pressure of up to about 20,000 psi or about 138 mPa.

It is contemplated, however, that the cap350may be designed to have any shape of configuration that is suitable for the application in which the focused output detonator100will be used. For example, and as illustrated inFIG.6, the cap350may have a planar surface.

According to an aspect and as illustrated inFIG.6, an insert/jet interrupter600may be disposed in or otherwise secured to an interior surface352of the cap350. The jet interrupter600may be configured to reduce the force of a resulting perforating jet formed upon detonation of the donor charge.

The jet interrupter600is illustrated in more detail inFIG.7. The jet interrupter600may have a substantially circular configuration or may be generally shaped to cover the open end316of the case310. According to an aspect, the jet interrupter600is a planar, disc-shaped element. According to an aspect, the jet interrupter600is formed from a metal (such as steel) or any other material that reduces the force of the perforating jet. The jet interrupter600may be formed from a metal, ceramic, composite, or glass.

According to an aspect, the jet interrupter600is formed from metal foam (not shown). The type of material selected to form the metal foam may be selected based on the specific shaped charge or explosive components, i.e., based on the specific application. In some embodiments, the metal foam includes at least one of aluminum, steel, iron, or combinations thereof. The metal foam may be composed of various metal alloys. In some embodiments, the metal foam is a porous irregular structure and may be formed from various methods, including gas injection within a metallic structure, powder metallurgy, casting, metallic deposition, sputter deposition, and/or heat treatment of aluminum powder. The metal foam may be bonded together with sheet metal composed of various metal alloys, such as steel.

One or more components of the focused output detonator100, such as the detonator shell200, the case310and/or the closure member350may include a material that pulverizes upon detonation/initiation of the detonator100. Rather than forming debris (including, for example, shrapnel that can result in obstructions in the wellbore), the detonator100forms a pulverized material that does not obstruct the wellbore and does not need to be retrieved from the wellbore. According to an aspect, the detonator shell200, the case310and/or the closure member350may be formed from materials including, but not limited to composites, plastics, plastics with glass fiber, ceramics, steel or glass. The detonator shell200, the case310and/or the closure member350may be formed from a zinc alloy including up to about 95% w/w zinc. The zinc alloy may include up to about 6% w/w of an aluminum copper alloy.

According to an aspect, the combined total weight of the explosive loads220,320housed in the detonator shell200and the focusing assembly300is up to about 10 grams. Alternatively, the combined total weight is 8 grams or less. The amount of explosive loads utilized in the focused output detonator100may generate a detonative force that is large enough to break through barriers and/or perforate a target. If the detonative force is too high, then a jet interrupter, such as the jet interrupter600described hereinabove and illustrated inFIG.6andFIG.7may be utilized.

FIGS.8-13each illustrate additional views of a focused output detonator100including a detonator shell200, a focuser300secured to a first end of the detonator shell200, and an initiator head700secured to an opposing end of the detonator shell200.

The detonator shell200may be configured substantially as described hereinabove and as illustrated in, for example,FIGS.1-6. Thus, for purpose of convenience, and not limitation, the features and characteristics of the detonator shell200are not repeated hereinbelow, to the extent that those features and characteristics are consistent with the disclosure of the focused output detonator illustrated inFIGS.8-13.

The focuser300may be configured substantially as described hereinabove and as illustrated in, for example,FIGS.1-6. Thus, for purpose of convenience, and not limitation, the features and characteristics of the focuser300are not repeated hereinbelow, to the extent that those features and characteristics are consistent with the disclosure of the focused output detonator illustrated inFIGS.8-13.

FIGS.8-13each illustrate the initiator head700being coupled to the first open end212of the body210of the detonator shell200. According to an aspect, the initiator head700includes an initiator head housing701extending in an axial direction. In the axial direction, at least a portion of the initiator head700is perpendicular to the longitudinal axis Y of the detonator shell200.

The initiator head housing701may be configured as a multi-part assembly that is snap-fitted or compressed together. For example, the initiator head housing701may include a first housing piece730and a second housing piece740. The first housing piece730and the second housing piece740may be engaged together. According to an aspect, the first housing piece730may be receivable in the second housing piece740, such that an interior space or a chamber is formed between the first and second housing pieces730,740. Alternatively, the housing701may be an integral or monolithic piece molded or additively manufactured around the circuit board210.

FIG.8,FIGS.10-11, andFIG.13further show that an exemplary embodiment of the first housing piece730. The first housing piece730includes a first plate732. A thickness direction of the first plate732may be substantially parallel to the axial direction. According to an aspect, the first plate732may be shaped as an annulus having a substantially circular periphery and a substantially circular through hole736(FIG.10andFIG.13). The through hole736may be structured to expose a line-in terminal712(described in further detail hereinbelow) to an exterior704of the housing701. The first plate732may further include a sloped wall720sloping from the first plate732in the axial direction toward the second housing piece740. The first housing piece730may further include a first outer peripheral wall734extending from the first plate732in the axial direction302. According to an aspect, the first outer peripheral wall734extends from an outer periphery of the first plate732.

FIG.9andFIG.11further shows that an exemplary embodiment of the second housing piece740. The second housing piece740may include a second plate742. A thickness direction of the second plate742may be substantially parallel to the axial direction. As further seen inFIG.9, an exemplary embodiment of the second plate742may be substantially circular in shape. The second plate742may further include through holes746structured to expose line-out and ground terminals (described in further detail hereinbelow) to the exterior704of the housing701. The second housing piece740may further include a second outer peripheral wall744extending from the second plate742in the axial direction.FIG.9andFIG.11show an exemplary embodiment in which the second outer peripheral wall744extends from an outer periphery of the second plate742.

As further seen inFIG.11andFIG.13, the first outer peripheral wall734and the second outer peripheral wall744may overlap in the axial direction, such that an interior space702is formed between the first plate732and the second plate742in the axial direction. In other words, the interior space702may be bounded by the first housing piece730and the second housing piece740. In an exemplary embodiment, a first housing piece radius of the first housing piece730may be smaller than a second housing piece radius of the second housing piece740. Thus, the first housing piece730may be received within the second housing piece740with the first outer peripheral wall734being provided between the first plate732and the second plate742in the axial direction702. Alternatively, the first housing piece radius may be larger than the second housing piece radius, and the second housing piece740may be received within the first housing piece730, with the second peripheral wall734being provided between the first plate732and the second plate742in the axial direction.

The first housing piece730and the second housing piece740may be dimensioned such that the first housing piece730and the second housing piece740fit snugly together so as not to separate under normal operating conditions. Alternatively, the first housing piece730and the second housing piece740may be provided with a coupling mechanism such as hook or protrusion and a complementary recess, so that the first housing piece730and the second housing piece740may snap together. Alternatively, the first outer peripheral wall734and the second outer peripheral wall744may be complementarily threaded so that the first housing piece730and the second housing piece740may screw together. Alternatively, the first housing piece730and the second housing piece740may be bonded together with adhesive.

A circuit board710is provided in the interior space702of the initiator head housing700. According to an aspect, a thickness direction of the circuit board710is substantially parallel with the axial direction. The circuit board710may be a printed circuit board and/or may include one or more surface mounted components. The arrangement of the circuit board710and the shape of the initiator head700may provide sufficient space in the interior space702to accommodate a variety of surface mounted components. In an exemplary embodiment, the surface mounted component of the circuit board710may be an integrated circuit (IC) with a dedicated function, a programmable IC, or a microprocessor IC.

In an embodiment and as illustrated inFIGS.8-15, a line-in terminal712, a ground terminal716and a fuse head/fuse240is operably connected to the circuit board710. As illustrated inFIGS.11-13, a line-out terminal714may also be connected to the circuit board710. The line-in terminal712may be provided on a first side of the circuit board710in the axial direction, and thereby the line-in terminal712may be provided on a first side of the housing701in the axial direction. The line-out terminal714and the ground terminal716may be provided on a second side of the circuit board710in the axial direction opposite to the first side. The line-out terminal714may be configured to output a signal received by the line-in terminal712, either directly or in response to processing by the circuit board710by being operably coupled to either the line-in terminal712or the circuit board710. Each of the line-in terminal712, the line-out terminal714and the ground terminal716may be accessible from the exterior704of the initiator head housing701. It is contemplated that the line-out terminal714may be particularly suited for selective firing of a plurality of perforating assemblies, such as perforating drones, connected to each other. Such perforating assemblies may be physically connected to each other using any number of securing means, such as, threads, bayonet connectors, pin and socket connectors, and the like. The line-out terminal714and/or a connector extending from the line-out terminal714may extend from the electronic circuit board230or a Control Interface Unit (CIU), such as the CIU described in US Publication No. 2020/0018139, published Jan. 16, 2020, which is commonly owned by DynaEnergetics Europe GmbH, and incorporated herein by reference.

According to an aspect, the fuse240is displaced from the circuit board710in the axial direction but is operably connected to the circuit board710. The circuit board710is configured to activate the fuse240in response to a control signal received at the line-in terminal712. According to an aspect, the line-out terminal714is operably connected to at least one of the circuit board and the line-in terminal. The ground terminal716is also operably connected to the circuit board.

The circuit board710may be configured to activate the fuse240in response to a control signal received at the line-in terminal712. For example, a user may send a firing signal via a firing panel. The firing signal may be received at the line-in terminal712, and the circuit board710, through ICs provided on the circuit board710, may process the firing signal and activate the fuse240. Additionally, the circuit board710may include a switch circuit configured to operably connect the line-out terminal714to the line-in terminal712in response to a predetermined switch signal.

According to an aspect, and as illustrated inFIG.10, for example, the initiator head housing701further includes a stem750. The stem750may extend in the axial direction from the housing701. In an exemplary embodiment, the stem750may be formed of the same material as the second housing piece740and may be integrally and/or monolithically formed with the second plate742. 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 inFIG.13, the stem750may include a stem outer peripheral wall752. The stem outer peripheral wall752may define a stem cavity754provided radially inward from the stem outer peripheral wall752. According to an aspect, a first discharge channel756and a second discharge channel758may connect the stem cavity754and the interior space702of the housing701. The first discharge channel756may accommodate therein a first discharge terminal759aoperably connected to the circuit board710. In other words, the first discharge terminal759amay extend from the circuit board710into the first discharge channel756. Similarly, the second discharge channel756may accommodate therein a second discharge terminal759boperably connected to the circuit board710. In other words, the second discharge terminal759bmay extend from the circuit board710into the second discharge channel758.

According to an aspect, a first fuse terminal762is operably connected to the first discharge terminal759a, and a second fuse terminal764is operably connected to the second discharge terminal759b. The circuit board710is configured to activate the fuse240in response to a control signal by discharging a stored voltage across the first fuse terminal762and the second fuse terminal764.

As seen inFIG.14andFIG.15, the initiator head700may engage with a holder ground terminal770. The holder ground terminal770may include a holder ground contact772. In an exemplary embodiment, the holder ground contact772may be punched from the material of the holder ground terminal770and then bent to a side of the holder ground terminal770. This may help to impart a spring-loaded action to the holder ground contact772and bias the holder ground contact772in a direction toward the initiator head700, thereby helping to ensure a more secure electrical contact between the ground terminal716and the holder ground contact772. According to an aspect, when the focused output detonator100is positioned within a drone (described in detail hereinbelow), the holder ground contact772is operably coupled to the ground terminal716.

FIG.14andFIG.15show that, in an exemplary embodiment of the holder ground terminal770, the holder ground contact772may be one of a plurality of holder ground contacts772. As seen inFIG.9, if the initiator head700includes a plurality of ground terminals716, then the plurality of holder ground contacts772provided a layer of redundancy for establishing a connection to ground. For example, even of one pair the ground terminals716and the holder ground contacts772fails to establish a secure electrical connection, a second pair of the ground terminals716and the holder ground contacts772may form a secure electrical connection.

As further seen inFIG.15, the initiator head700may further engage with a holder ground bar774extending from the holder ground terminal770. The holder ground bar774may contact a ground when the focused output detonator100is received within a drone, such as a perforating drone. In other words, the holder ground terminal770may be operably connected to ground, for example through the holder ground bar774.

As further seen in the exemplary embodiment ofFIG.15, the initiator head700may engage with a through-wire terminal780. It is contemplated that the through-wire terminal780may be particularly suited for providing a line of communication between a plurality of perforating assemblies, such as perforating drones, connected to each other. The through-wire terminal780may include a through-wire contact782. In an exemplary embodiment, the through wire contact782may be punched from the material of the through-wire terminal420and then bent to a side of the through-wire terminal780. This may help to impart a spring-loaded action to the through-wire contact782and bias the through-wire contact782in a direction toward the initiator head700, thereby helping to ensure a more secure electrical contact between the through-wire terminal780and the through-wire contact782. In other words, when the focused output detonator100is positioned within the drone, the through-wire contact782may be operably coupled to the through-wire terminal780.

FIG.15shows that, in an exemplary embodiment of the through-wire terminal780, the through-wire contact782may be one of a plurality of through-wire contacts782. If the initiator head700includes a plurality of line-out terminals714, then the plurality of through-wire contacts782provided a layer of redundancy for establishing an electrical connection. For example, even if one pair of the line-out terminals714and the through-wire contacts782fails to establish a secure electrical connection, a second pair of the line-out terminals714and the through-wire contacts782may form a secure electrical connection.

It is contemplated that the focused output detonator100described herein may be provided in an autonomous perforating drone1200for downhole delivery of one or more wellbore tools. Such autonomous perforating drones1200are described and shown in US Patent Application Publication No. US2020/0018139 published Jan. 16, 2020, which is commonly-owned and assigned to DynaEnergetics Europe GmbH and incorporated herein by reference in its entirety to the extent that it is consistent with this disclosure.

Detonation of shaped charges may be initiated with an electrical pulse or signal supplied to a detonator. The detonator of the autonomous perforating drone may include a focused output detonator100as shown inFIGS.1-6andFIGS.8-15, and described hereinabove. The focused output detonator100may be located in a control module section, a perforating assembly section, or at a position or intersection therebetween. The focused output detonator100may initiate the shaped charges of the autonomous perforating drones either directly or through an intermediary structure such as a detonating cord.

An electrical selective sequence signal may be sent from, e.g., a programmable electronic circuit to the focused output detonator100to initiate the focused output detonator100when the autonomous perforating drone reaches at least one of a threshold pressure, temperature, horizontal orientation, inclination angle, depth, distance traveled, rotational speed, and position within the wellbore. The threshold conditions may be measured by any known devices consistent with this disclosure including a temperature sensor, a pressure sensor, a positioning device as a gyroscope and/or accelerometer (for horizontal orientation, inclination angle, and rotational speed), and a correlation device such as a casing collar locator (CCL) or position determining system (for depth, distance traveled, and position within the wellbore). The electrical selective sequence signal may include one or more of an addressing signal for activating one or more power components of the focused output detonator100, an arming signal for activating a detonator firing assembly such as a trigger circuit or capacitor, and a detonating signal for detonating the focused output detonator100. The threshold values and other instructions for addressing, arming, and/or detonating the focused output detonator100may be taught to the programmable electronic circuit by, for example and without limitation, a control unit at a factory or assembly location or at the surface of the wellbore prior to deploying the autonomous perforating drone into the wellbore. In an aspect, the selective sequence signal may be one or more digital codes including or more digital codes uniquely configured for the focused output detonator100of each particular autonomous perforating drone.

According to the exemplary configuration, detonating the focused output detonator100will cause the focuser300to detonate. In an aspect, the focuser300may be designed, for example and without limitation, to have an explosive power for contributing to breaking apart the drone upon detonation. In another aspect, the focuser300may be explosive and/or explosive/liner assembly as in a typical shaped charge but may be pressed into a plastic housing instead of contained within a metal casing.

The focuser300may be configured as an explosive shaped charge, such as a donor charge301or an encapsulated and hydraulically sealed donor charge as described hereinabove. The focuser300is designed to create a directed perforating jet upon detonation. According to the exemplary configuration, detonating the focused output detonator100will cause the focuser300to detonate. In an aspect, the focuser300may be designed, for example and without limitation, to have an explosive power for contributing to breaking apart the drone upon detonation. In another aspect, the focuser300may be explosive and/or explosive/liner assembly as in a typical shaped charge but may be pressed into a plastic housing instead of contained within a metal casing.

According to an aspect, a ballistic interrupt is retained within the drone body through an opening in the drone body. The ballistic interrupt140in the exemplary embodiment and for purposes of preventing accidental or unintended detonation of the shaped charges is positioned, in any event, between the focused output detonator100within the control module section and a shaped charge initiator (detonating cord, booster or explosive pellets) configured for being initiated by the focused output detonator100in the control module.

This disclosure, in various embodiments, configurations and aspects, includes components, methods, processes, systems, and/or apparatuses as depicted and described herein, including various embodiments, sub-combinations, and subsets thereof. This disclosure contemplates, in various embodiments, configurations and aspects, the actual or optional use or inclusion of, e.g., components or processes as may be well-known or understood in the art and consistent with this disclosure though not depicted and/or described herein.

The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

In this specification and the claims that follow, reference will be made to a number of terms that have the following meanings. The terms “a” (or “an”) and “the” refer to one or more of that entity, thereby including plural referents unless the context clearly dictates otherwise. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. Furthermore, references to “one embodiment”, “some embodiments”, “an embodiment” and the like are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term such as “about” is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Terms such as “first,” “second,” “upper,” “lower” etc. are used to identify one element from another, and unless otherwise specified are not meant to refer to a particular order or number of elements.

As used herein, the terms “may” and “may be” indicate a possibility of an occurrence within a set of circumstances; a possession of a specified property, characteristic or function; and/or qualify another verb by expressing one or more of an ability, capability, or possibility associated with the qualified verb. Accordingly, usage of “may” and “may be” indicates that a modified term is apparently appropriate, capable, or suitable for an indicated capacity, function, or usage, while taking into account that in some circumstances the modified term may sometimes not be appropriate, capable, or suitable. For example, in some circumstances an event or capacity can be expected, while in other circumstances the event or capacity cannot occur—this distinction is captured by the terms “may” and “may be.”

As used in the claims, the word “comprises” and its grammatical variants logically also subtend and include phrases of varying and differing extent such as for example, but not limited thereto, “consisting essentially of” and “consisting of.” Where necessary, ranges have been supplied, and those ranges are inclusive of all sub-ranges therebetween. It is to be expected that the appended claims should cover variations in the ranges except where this disclosure makes clear the use of a particular range in certain embodiments.

The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique.

This disclosure is presented for purposes of illustration and description. This disclosure is not limited to the form or forms disclosed herein. In the Detailed Description of this disclosure, for example, various features of some exemplary embodiments are grouped together to representatively describe those and other contemplated embodiments, configurations, and aspects, to the extent that including in this disclosure a description of every potential embodiment, variant, and combination of features is not feasible. Thus, the features of the disclosed embodiments, configurations, and aspects may be combined in alternate embodiments, configurations, and aspects not expressly discussed above. For example, the features recited in the following claims lie in less than all features of a single disclosed embodiment, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

Advances in science and technology may provide variations that are not necessarily express in the terminology of this disclosure although the claims would not necessarily exclude these variations.