Positioning device for shaped charges in a perforating gun module

A positioning device includes a shaped charge holder. A plurality of shaped charge receptacles formed in the shaped charge holder are configured to arrange a plurality of shaped charges in a desired orientation. The shaped charges are detonated by a detonator in response to an initiation signal. The positioning device may be secured in a perforating gun module, with vertical and horizontal movement of the positioning being inhibited in the perforating gun module.

BACKGROUND OF THE DISCLOSURE

Hydrocarbons, such as fossil fuels (e.g. oil) 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 casing pipes after drilling, a perforating gun assembly, or train or string of multiple perforating gun assemblies, are lowered into the wellbore, and positioned adjacent one or more hydrocarbon reservoirs in underground formations.

Assembly of a perforating gun requires assembly of multiple parts. Such parts typically include a housing or outer gun barrel. An electrical wire for communicating from the surface to initiate ignition, a percussion initiator and/or a detonator, a detonating cord, one or more charges which are held in an inner tube, strip or carrying device and, where necessary, one or more boosters are typically positioned in the housing. Assembly of the perforating gun typically includes threaded insertion of one component into another by screwing or twisting the components into place. Tandem seal adapters/subs are typically used in conjunction with perforating gun assemblies to connect multiple perforating guns together. The tandem seal adapters are typically configured to provide a seal between adjacent perforating guns. Some tandem seal adapters may be provided internally or externally between adjacent perforating guns, which, in addition to requiring the use of multiple parts or connections between the perforating guns, may increase the length of each perforating gun and may be more expensive to manufacture. One such system is described in PCT Publication No. WO 2015/179787A1 assigned to Hunting Titan Inc.

The perforating gun includes explosive charges, typically shaped, hollow or projectile charges, which are initiated to perforate holes in the casing and to blast through the formation so that the hydrocarbons can flow through the casing. The explosive charges may be arranged in a hollow charge carrier or other holding devices. Once the perforating gun(s) is properly positioned, a surface signal actuates an ignition of a fuse or detonator, which in turn initiates a detonating cord, which detonates the explosive charges to penetrate/perforate the casing and thereby allow formation fluids to flow through the perforations thus formed and into a production string. Upon detonation of the explosive charges, debris typically remains inside the casing/wellbore. Such debris may include shrapnel resulting from the detonation of the explosive charges, which may result in obstructions in the wellbore. Perforating gun assemblies may be modified with additional components, end plates, internal sleeves, and the like in an attempt to capture such debris. U.S. Pat. No. 7,441,601 to GeoDynamics Inc., for example, describes a perforating gun assembly having an inner sleeve configured with pre-drilled holes that shifts in relation to an outer gun barrel upon detonation of the explosive charges in the perforating gun, to close the holes formed by the explosive charges. Such perforating gun assemblies require numerous components, may be costly to manufacture and assemble, and may reduce/limit the size of the explosive charges, in relation to the gun diameter, which may be compatible with the gun assembly.

There is a need for an improved perforating gun assembly that does not require the use of tandem seal adapters or tandem subs to facilitate a sealed connection between perforating gun assemblies. There is a further need for a perforating gun assembly that includes an efficient design for capturing debris resulting from detonation of a plurality of shaped charges.

BRIEF DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Embodiments of the disclosure are associated with a positioning device. The positioning device includes a shaped charge holder configured for arranging/positioning a plurality of shaped charges therein. According to an aspect, the shaped charges are positioned in an XZ-plane, in an outward, radial arrangement about a central-axis/Y-axis/central Y-axis of the shaped charge holder. The shaped charges may be designed so that, regardless of their sizes, they create perforating tunnels having a geometry (such as a length and width) that cumulatively facilitates a flow rate that is equivalent to the flow rate facilitated by other shaped charges of different sizes. Each shaped charge includes an open front end, and a back wall including an initiation point. A detonator may be positioned centrally within the shaped charge holder, adjacent the initiation point. According to an aspect, the detonator is a wireless detonator and the shaped charges are directly initiated by the detonator in response to an initiation signal.

The present embodiments may further be associated with a positioning device for a plurality of shaped charges. The positioning device includes a first end and a second end, and a shaped charge holder extending between the first and second ends. The shaped charge holder includes a plurality of shaped charge receptacles radially arranged in an XZ-plane about a Y-axis of the shaped charge holder. Each of the receptacles is configured for receiving one of the shaped charges, so that the received shaped charges are similarly radially arranged in the XZ-plane about the central Y-axis of the shaped charge holder. According to an aspect, the shaped charge receptacles include a depression and an opening formed in the depression. An elongated cavity may extend through the positioning device from the first end to the second end. The elongated cavity is adjacent each of the shaped charge receptacles and is in communication with the elongated opening. According to an aspect, a detonator is positioned in the elongated opening and configured to initiate the shaped charges simultaneously, in response to an initiation signal.

Further embodiments of the disclosure may be associated with a positioning device including a first end, a second end, and an elongated cavity/lumen extending through the positioning device from the first end to the second end. A shaped charge holder is included in the positioning device and extends between the first and second ends. The shaped charge holder is configured substantially as described hereinabove, and each of its shaped charge receptacles is configured for receiving one of the shaped charges. According to an aspect, the elongated opening of the positioning device is configured for retaining a detonator therein and is adjacent the shaped charge receptacles. The arrangement of the detonator in the elongated opening facilitates direct and simultaneous initiation of the shaped charges via the detonator, which may occur in response to an initiation signal. According to an aspect, the positioning device may further include at least one rib. The rib outwardly extends from the positioning device. When the holder is positioned in a perforating gun module/carrier, the fin may engage with an inner surface of the perforating gun module to prevent movement of the positioning device, and thus the shaped charges, vertically in the perforating gun module.

Embodiments of the disclosure may further be associated with a shaped charge for use with a shaped charge holder, or a positioning device including a shaped charge holder, configured substantially as described hereinabove. The shaped charge includes a substantially cylindrical/conical case having an open front end, and a back wall having an initiation point extending there through, and at least one cylindrical side wall extending between the open front end and the back wall. An explosive load is disposed within the hollow interior of the case, and is positioned so that it is adjacent at least a portion of an internal surface of the case. According to an aspect, a liner is pressed into or positioned over the explosive load. The liner may be seated within the case adjacent the internal surface to enclose the explosive load therein. According to an aspect, at least one of the internal surface, the liner geometry and/or liner constituents, and the explosive load is modified to change the shape of a perforating jet formed upon detonation of the shaped charge. The resulting perforation jet creates a perforating tunnel that has a geometry that facilitates a flow rate or hydraulic fracturing that is equivalent to the flow rate or the hydraulic fracturing typically facilitated by another shaped charge of a different size or composition. According to an aspect, the side wall includes an engagement member outwardly extending from an external surface of the side wall. The engagement member is configured for coupling the shaped charge within a shaped charge receptacle of a shaped charge holder configured substantially as described herein. The shaped charge does not require the use of detonating cord guides at the back of the shaped charge and eliminates the need for a turning process during manufacture of the shaped charge. This may result in reduced manufacturing costs as the shaped charge has less contoured surfaces as standard shaped charges.

Further embodiments of the disclosure may be associated with a perforating gun module. The perforating gun module includes a housing having a first housing end and a second housing end. A chamber extends from the first housing end towards the second housing end, and a positioning device is secured in the chamber. The positioning device may be configured substantially as defined hereinabove. According to an aspect, the positioning devices includes the shaped charge holder including shaped charge receptacles that are radially arranged in an XZ-plane about a Y-axis of the shaped charge holder. The positioning device includes at least one rib extending therefrom and engaging with an inner surface of the housing of the perforating gun module, thereby reducing movement of the positioning device, and thus the orientation of the shaped charges, within the perforating gun module. The shaped charge holder may be configured to house and retain a detonator in an elongated cavity, and a plurality of shaped charges may be arranged in the shaped charge receptacles. The detonator is arranged so that it is directly energetically coupled to the shaped charges, which may eliminate the requirement for use of a detonating cord to activate the shaped charges. According to an aspect, the housing of the housing of the perforating gun module is specially designed to capture a resulting mass created by the activation of the shaped charges. This helps to minimize debris that may remain in the wellbore after detonation of the shaped charges.

Embodiments of the disclosure may further be associated with a method of making the perforating gun module described herein. The method includes forging a housing from a solid metal material and providing a positioning device for being received in a chamber of the housing. According to an aspect, the positioning device is formed from an injection molded, casted, or 3D printed plastic material or 3-D milled and cut from solid plastic bar stock. The positioning device may be configured substantially as described hereinabove. The positioning device is arranged within a chamber of the housing so that the shaped charges are positioned in an XZ-plane, in an outward, radial arrangement, about a Y-axis of the shaped charge holder.

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

As used herein, the term “energetically” may refer to a detonating/detonative device that, when detonated/or activated, generates a shock wave impulse that is capable of reliably initiating an oilfield shaped charge, booster or section of detonating cord to a high order detonation.

The terms “pressure bulkhead” and “pressure bulkhead structure” shall be used interchangeably, and shall refer to an internal, perforating gun housing compartment of a select fire sub assembly. In an embodiment, it also contains a pin assembly and allows the electrical passage of a wiring arrangement. The bulkhead structures may include at least one electrically conductive material within its overall structure.

For purposes of illustrating features of the embodiments, simple examples will now be introduced and referenced throughout the disclosure. Those skilled in the art will recognize that these examples are illustrative and not limiting and are provided purely for explanatory purposes. As other features of a perforating gun assembly are generally known (such as detonator and shaped charge design structures), for ease of understanding of the current disclosure those other features will not be otherwise described herein except by reference to other publications as may be of assistance.

FIGS. 1-2illustrate a positioning device10configured for arranging a plurality of shaped charges120(FIG. 6) in a selected configuration. The shaped charges120may be positioned in an XZ-plane, in an outward, radial arrangement, about a Y-axis of the shaped charge holder20; the Y-axis in the figures is the central axis of the shaped charge holder20. The positioning device10may be configured as a unitary structure formed from a plastic material. According to an aspect, the positioning device10is formed from an injection molded material, a casted material, a 3D printed or 3-D milled material, or a machine cut solid material. Upon detonation of the shaped charges120positioned in the shaped charge holder20, the positioning device may partially melt/soften to capture any shrapnel and dust generated by the detonation.

The positioning device10includes a first end22and a second end24, and a shaped charge holder20extending between the first and second ends22,24. According to an aspect, the shaped charge holder20includes a plurality of shaped charge receptacles30. The receptacles30are arranged between the first and second ends22,24of the positioning device10. The shaped charge receptacles30may be radially arranged in the XZ-plane about the Y-axis, i.e., central axis, of the shaped charge holder20, each being configured to receive one of the shaped charges120.

According to an aspect, the shaped charge receptacles30may include a depression/recess32that extends inwardly into the positioning device10. An opening/slot34is formed in the depression30. The opening34is configured to facilitate communication between contents of the depression32(i.e., the shaped charges120) and a detonative device that extends through the positioning device10. In an embodiment and as illustrated inFIG. 5, the opening34of each of the shaped charge receptacles30, and the shaped charges120, is spaced from about 60° to about 120° from each other. According to an aspect, the shaped charge receptacles30may be spaced apart from each other equidistantly, which may aid in reducing the formation breakdown pressure during hydraulic fracturing. The positioning device10may include 2, 3, 4, 5, 6 or more receptacles30, depending on the needs of the application.

The shaped charge receptacles30may be configured to receive shaped charges120of different configurations and/or sizes. As would be understood by one of ordinary skill in the art, the geometries of the perforating jets and/or perforations (holes or perforating holes) that are produced by the shaped charges120upon detonation depends, at least in part, on the shape of the shaped charge case, the shape of the liner and/or the blend of powders included in the liner. The geometries of the perforating jets and holes may also depend on the quantity and type of explosive load included in the shaped charge. The shaped charges120may include, for example, substantially the same explosive gram weight, the interior surface of the shaped charge case and/or the design of the liner may differ for each shaped charge120in order to produce differently sized or shaped perforations.

According to an aspect, the receptacles30are configured to receive at least one of 3 g to 61 g shaped charges. It is contemplated, for example, that the receptacles may be sized to receive 5 g, 10 g, 26 g, 39 g and 50 g shaped charges120. Adjusting the size of the shaped charges120(and thereby the quantity of the explosive load in the shaped charges120) positioned in the shaped charge receptacles30may impact the size of the entrance holes/perforations created in a target formation upon detonation of the shaped charges120.

The positioning device10may include three (3) shaped charges receptacles30, with a shaped charge120being positioned in each receptacle30. Upon detonation of the shaped charges120, three (3) perforating holes having an equal entrance hole diameter of an amount ranging from about 0.20 inches to about 0.55 inches are formed. To be sure, the equal entrance hole diameter of the perforations will include a deviation of less than 10%. For example, three specially designed shaped charges120, each including 10 g of explosive load, may be installed in a positioning device10. Upon detonation of these shaped charges120, they may perform equivalent to a standard shaped charge carrier that has three standard shaped charges that each include 22.7 g explosive load. The enhanced performance of the specially designed shaped charges120may be facilitated, at least in part, may the type of explosive powder selected for the explosive load, the shape and constituents of the liner and the contours/shape of the internal surface of the shaped charge case.

The combined surface area of the hole diameters may be equivalent to the total surface area that would be formed by an arrangement of 2, 4, 5, 6 or more standard shaped charges of a standard perforating gun. The ability of the shaped charge receptacles30to receive shaped charges120of different sizes or components helps to facilitate a shot performance that is equivalent to that of a traditional shaped charge carrier including 2, 4, 5, 6 or more shaped charges. Thus, without adjusting the quantity/number of the shaped charges120and/or the receptacles30of the positioning device10, the total surface area of the perforations (i.e., the area open to fluid flow) created by detonating the shaped charges120is effectively adjusted based on the size and type of the shaped charges120utilized in the positioning device10. This may facilitate a cost-effective and efficient way of adjusting the optimal flow path for fluid in the target formation, without modifying the arrangement or quantity of the receptacles30.

According to an aspect, the positioning device10includes one or more mechanisms that help to guide and/or secure the shaped charges within the shaped charge receptacles30. The positioning device may include a plurality of shaped charge positioning blocks/bars85outwardly extending from the shaped charge holder20. The positioning blocks85may help to guide the arrangement, mounting or placement of the shaped charges120within the shaped charge receptacles30. The positioning blocks85may be contoured to correspond to a general shape of the shaped charges120, such as conical or rectangular shaped charges. According to an aspect, the positioning blocks85provides added strength and stability to the shaped charge holder20and helps to support the shaped charges120in the shaped charge holder20.

According to an aspect, the positioning device10further includes a plurality of retention mechanisms80outwardly extending from the holder20. The retention mechanisms80may be adjacent each of the shaped charge receptacles30. As illustrated inFIG. 1andFIG. 2, the retention mechanisms80may be arranged in a spaced apart configuration from each other. Each retention mechanism80may be adjacent one shaped charge positioning block85. For instance, each member of a pair of the retention mechanisms80may be spaced at about a 90° degree angle from an adjacent retention mechanism80. The pair of retention mechanisms80may be configured to retain one of the shaped charges120within one shaped charge receptacle30. The retention mechanisms80may each include an elongated shaft81, and a hook83that extends outwardly from the elongated shaft. The hook83is at least partially curved to engage with a cylindrical wall of the shaped charges120, thereby helping to secure the shaped charge120within its corresponding shaped charge receptacle30, and thus the shaped charge holder20.

According to an aspect, the depression32of the shaped charge receptacles30, in combination with at least one of the retention mechanisms80and the shaped charge positioning blocks85, aid in mechanically securing at least one of the shaped charges120within the positioning device10.

An elongated cavity/lumen40extends through the positioning device10, from the first end22to the second end24. The elongated cavity40may be centrally located within the positioning device10and is adjacent each of the shaped charge receptacles30, and thereby the shaped charge120housed in the receptacles30.

The elongated cavity40may be configured for receiving and retaining a detonative device therein. According to an aspect, the detonative device includes a detonator50(FIG. 11). The detonator50may be positioned centrally within the shaped charge holder20. According to an aspect and as illustrated inFIG. 6, the plurality of shaped charges120housed in the shaped charge holder20includes an open front end320and a back wall330having an initiation point331extending therethrough. The detonator50is substantially adjacent the initiation point331and is configured to simultaneously initiate the shaped charges120in response to an initiation signal, such as a digital code.

According to an aspect, the detonator50is a wireless push-in detonator. Such detonators are described in U.S. Pat. Nos. 9,605,937 and 9,581,422, both commonly owned and assigned to DynaEnergetics GmbH & Co KG, each of which is incorporated herein by reference in its entirety. According to an aspect, the detonator50includes a detonator head52and a detonator body54(FIG. 11) extending from the detonator head52. The detonator head52includes an electrically contactable line-in portion, an electrically contactable line-out portion, and an insulator positioned between the line-in and line-out portions, wherein the insulator electrically isolates the line-in portion from the line-out portion. The detonator body54may be energetically coupled to or may energetically communicate with each of the shaped charges120. According to an aspect, the detonator body54may include a metal surface, that provides a contact area for electrically grounding the detonator50.

The positioning device10may include passageways28that help to guide a feed through/electrical wire260(FIG. 9) from the detonator50to contact a bulkhead assembly/pressure bulkhead assembly230(FIG. 9). As illustrated inFIGS. 1-2andFIG. 11, the passageway28may be formed at the second end24of the positioning device10and receives and guides the feed through wire/electrical wire260to the bulkhead assembly230.

The positioning device10may be configured as a modular device having a plurality of connectors26that allows the positioning device10to connect to other adjacent positioning devices, adjacent shaped charge holders, and spacers, as illustrated inFIG. 4. The positioning device10may be configured to engage or connect to charge holders, spacers and connectors described in U.S. Pat. Nos. 9,494,021 and 9,702,680, both commonly owned and assigned to DynaEnergetics GmbH & Co KG, each of which is incorporated herein by reference in its entirety.

The connectors26each extend along the central Y-axis of the shaped charge holder20. According to an aspect, the connectors26includes at least one of a plurality of plug connectors/pins27aand a plurality of receiving cavities/sockets27b. The plurality of receiving cavities/sockets27bare shown inFIG. 1andFIG. 2on the opposite end of the positioning device10, for receiving plug connectors27afrom a downstream positioning device. The plug connectors27aoutwardly extend from the first or second end22,24, and the receiving cavities27binwardly extend into the positioning device10from the first or second end22,24. The plug connectors27aare configured for being inserted and at least temporarily retained into the receiving cavities27bof the adjacent positioning device, shaped charge holder, spacer or other connectors, while the receiving cavities27bare configured to receive plug connectors27aof another adjacent positioning device, charge holder, spacer or other components. When the first end22includes plug connectors27a, the second end24includes receiving cavities27bthat are configured to receive and retain the plug connectors of the adjacent positioning device, charge holder, spacer or other components. According to an aspect, the plug connectors27aare mushroom-shaped, which may aid in the retention of the plug connectors27ain the receiving cavities.

Further embodiments of the disclosure are associated with a positioning device110, as illustrated inFIGS. 3-5 and 8-11. The positioning device110includes a first end22and a second end24. According to an aspect, the first end22of the positioning device110may be contoured to retain a detonator head52(FIG. 8andFIG. 12B) therein. A shaped charge holder20extends between the first and second ends22,24of the positioning device110. For purposes of convenience, and not limitation, the general characteristics of the shaped charge holder20applicable to the positioning device110, are described above with respect to theFIGS. 1-2, and are not repeated here.

Similar to the shaped charge holder described hereinabove with reference toFIGS. 1-2, the shaped charge holder20illustrated inFIG. 3includes a plurality of shaped charge receptacles30, a plurality of retention mechanisms80and a plurality of positioning blocks85, which are configured substantially as described hereinabove with respect toFIGS. 1-2. Thus, for purpose of convenience, and not limitation, the features and characteristics of the receptacles30, the retention mechanisms80and the positioning blocks85of the positioning block110are not repeated here.

The positioning device110further includes an elongated cavity/lumen40extending through a length of the positioning device110. The elongated cavity40extends from the first end22to the second end24, adjacent each of the shaped charge receptacles30, and is configured for receiving and retaining a detonator50.

FIG. 10illustrates the detonator50positioned in the elongated cavity40. The detonator50is configured to initiate the shaped charges120simultaneously in response to an initiation signal. As described hereinabove, the detonator50may be a wireless push-in detonator. The detonator50of the positioning device110may be configured substantially as the detonator50of the positioning device10described hereinabove with respect toFIGS. 1-2, thus for purposes of convenience and not limitation, the various features of the detonator50for the positioning device10are not repeated hereinbelow.

The detonator50of the positioning device110includes a detonator head52and a detonator body54is energetically coupled to each of the shaped charges120. The elongated cavity40may be stepped or contoured to receive the head52and body54of the detonator50. According to an aspect and as illustrated inFIG. 10, the elongated cavity40includes a first cavity42and a second cavity44extending from the first cavity42. The first cavity42extends from and is adjacent the first end22of the positioning device110, while the second cavity44extends from the first cavity42towards the second end24. The first cavity42is larger than the second cavity44and is configured for receiving the detonator head52, while the second cavity44is configured for receiving the detonator body54.

According to an aspect, the positioning device110may be equipped with means for maintaining the positioning device in a preselected position in a perforating gun module200. The positioning device110may include at least one rib/fin160outwardly extending from the positioning device110.FIG. 3illustrates ribs160radially extending from the positioning device110and being arranged between the first end22of the positioning device110and the shaped charge holder20. The ribs160may be substantially equal in length with each other and may be configured to engage with an interior surface of a perforating gun module200, as illustrated in, for example,FIGS. 8-11.

The positioning device110may further include a plate70at least partially extending around the positioning device110. The plate70may be disposed/arranged between the first end22and the rib160.FIG. 3illustrates a protrusion/anti-rotation key74extending from a peripheral edge72of the plate70. The protrusion74may be configured to secure the positioning device110within a perforating gun module200, and to prevent rotation of the positioning device110and the shaped charge holder20within the perforating gun module200. As illustrated inFIGS. 8-11andFIG. 12B, the protrusion74may be configured to engage with an inner surface220(or a slot222) of a housing210of the perforating gun module200, which helps ensure that the shaped charges120are maintained in their respective positions with respect to the perforating gun module200. According to an aspect, the plate70is sized and dimensioned to capture debris resulting from detonation of the plurality of shaped charges120. As illustrated inFIG. 3, the plate70has a larger surface area than the ribs160, such that it is able to collapse with at least one of the shaped charge holder20and the ribs160, and capture any debris generated by the detonation of the shaped charges120, thereby reducing the amount (i.e., number of individual debris) that may need to be retrieved from the wellbore.

The positioning device110further includes a disk25outwardly and circumferentially extending from the positioning device110. The disk is arranged between the first end22and the plate70and, as illustrated inFIG. 8andFIG. 9, may help to create an isolation chamber280for the detonator head52. The isolation chamber280may protect and isolate the detonator50from lose metallic particles, shards, machine metal shavings and dust, or substantially minimize the detonator head52from such exposure, that may negatively impact the functionality of the detonator50and cause an electrical short circuit in the system.

According to an aspect, one or more components of the positioning device110may be configured with a passageway28. The passageway28may formed in at least one of the disk25(FIG. 12B), the plate70(FIG. 12B) and the second end24(FIG. 304) of the body20. The passageway28receives and guides a feed through wire/electrical wire260from the detonator50to the second end of the positioning device110, wherein the wire260contacts a bulkhead assembly/rotatable bulkhead assembly230.

As illustrated inFIGS. 8-11andFIG. 12B, a ground bar90may be arranged on or otherwise coupled to the positioning device110. The ground bar90is secured to the positioning device110, between the first end22and the plate70. According to an aspect, a support member82extends from the positioning device110, between the ground bar90and the plate70. The support member82is configured to prevent movement of the ground bar90along the central Y-axis of the shaped charge holder20, to ensure that the ground bar90is able to contact a portion of an adjacent perforating gun module.FIG. 14shows the ground bar90in more detail. The ground bar90may include a centrally-arranged opening92having a plurality of engagement mechanisms93, and one of more slots94to facilitate the ground bar90being secured to the positioning device110and to facilitate the engagement of the ground bar90with the adjacent perforating gun module. According to an aspect, the ground bar90is formed from a stamped, laser cut, or water-jet cut sheet of metal. The ground bar90may be formed from at least one of stainless steel, brass, copper, aluminum or any other electrically conductive sheeted material which can be stamped and re-worked, water jet cut or laser cut.

According to an aspect, and as illustrated in at leastFIGS. 4, 11, and 17, the positioning device110may be connectable to adjacent devices or components of a perforating gun module200. In an embodiment, at least one of the first end22and the second end24includes a plurality of connectors26extending along the central Y-axis of the charge holder20. The connectors26provide for a modular connection between the positioning device110and at least one of an adjacent positioning device, an adjacent shaped charge holder and a spacer including corresponding connectors. The connectors26of the positioning device110may be configured substantially as the connectors26of the positioning device10described hereinabove with respect toFIGS. 1-2, thus for purposes of convenience and not limitation, the various features of the connectors26of the positioning device10are not repeated here.

In an embodiment and as shown inFIG. 11, the shaped charges120is a first set of shaped charges, and a second set of shaped charges120′ is supported in a separate shaped charge holder20′ connected to the positioning device110. The separate shaped charge holder20′ may be included in the positioning device10illustrated inFIGS. 1-2. The separate shaped charge holder20′ includes a plurality of shaped charge receptacles30extending between first and second ends22,24of the separate shaped charge holder20′. The receptacles30are radially arranged in an XZ-plane about a central Y-axis of the separate shaped charge holder20′, each receptacle30retaining one of the shaped charges120′.

An elongated cavity40extends from the first end22to the second end24of the separate shaped charge holder20′ and is configured for retaining a detonation extender55therein. According to an aspect, the detonation extender55includes a detonating cord or a booster device56. As illustrated inFIG. 11, when the positioning device110is connected to the separate shaped charge holder20′, the detonation extender55is configured to abut an end of the detonator body54and extend from the elongated opening40of the positioning device110into the elongated opening40of the separate shaped charge holder20′ so the detonator extender is adjacent initiation points331of the separate shaped charges120′. The detonation extender55is adjacent a plurality of openings34formed in the shaped charge receptacles of the separate shaped charge holder20′. When the detonator50is activate, a detonation energy from the detonator50simultaneously activates the shaped charges120of the first set of shaped charges and the detonation extender55. The detonation extender55thereafter generates a detonation wave, which simultaneously activates the second set of shaped charges120′. Once all the charges120,120′ have detonated, the positioning device110and the separate charge holder20′ forms a resulting mass111(FIGS. 13A-13B) and limits the amount of debris generated upon detonation of the shaped charges.

According to an aspect, the shaped charges120for use with the aforementioned positioning devices10/110illustrated inFIGS. 1-5may be specially configured to be secured in a shaped charge holder20/20′ (collectively shaped charge holder20) described hereinabove. According to an aspect and as illustrated inFIG. 6, a shaped charge120for use at least one of a positioning device110and a shaped charge holder20) includes a substantially cylindrical/conical case310. The conical case310includes an open front end320, a back wall330having an initiation point331extending therethrough, and at least one cylindrical side wall340extending between the open front end320and the back wall330.

The shaped charge120further includes a cavity322defined by the side wall340and the back wall330. An explosive load324is disposed within the cavity322. According to an aspect, the explosive load324includes at least one of pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine/cyclotetramethylene-tetranitramine (HMX), 2,6-Bis(picrylamino)-3,5-dinitropyridine/picrylaminodinitropyridin (PYX), hexanitrostibane (HNS), triaminotrinitrobenzol (TATB), and PTB (mixture of PYX and TATB). According to an aspect, the explosive load324includes diamino-3,5-dinitropyrazine-1-oxide (LLM-105). The explosive load may include a mixture of PYX and triaminotrinitrobenzol (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.

As illustrated inFIG. 6, a liner326is disposed adjacent the explosive load324. The liner326is configured for retaining the explosive load324within the cavity322. In the exemplary embodiment shown inFIG. 6, the liner326has a conical configuration, however, it is contemplated that the liner326may be of any known configuration consistent with this disclosure. The liner326may be made of a material selected based on the target to be penetrated and may include, for example and without limitation, a plurality of powdered metals or metal alloys that are compressed to form the desired liner shape. Exemplary powdered metals and/or metal alloys include copper, tungsten, lead, nickel, bronze, molybdenum, titanium and combinations thereof. In some embodiments, the liner326is made of a formed solid metal sheet, rather than compressed powdered metal and/or metal alloys. In another embodiment, the liner326is made of a non-metal material, such as glass, cement, high-density composite or plastic. Typical liner constituents and formation techniques are further described in commonly-owned U.S. Pat. No. 9,862,027, which is incorporated by reference herein in its entirety to the extent that it is consistent with this disclosure. When the shaped charge120is initiated, the explosive load324detonates and creates a detonation wave that causes the liner326to collapse and be expelled from the shaped charge120. The expelled liner326produces a forward-moving perforating jet that moves at a high velocity

According to an aspect, the cylindrical side wall portion340includes a first wall342outwardly extending from a flat surface332of the back wall330, a second wall344outwardly extending from the first wall342, and a third wall346upwardly extending from the second wall344towards the open front end320. The third wall346may be uniform in width as it extends from the second wall344to the open from end320.

An engagement member350outwardly extends from an external surface341of the side wall340. As illustrated inFIG. 6, the engagement member350extends from the first wall342, at a position adjacent the second wall344. As illustrated inFIG. 5, the engagement member350may be configured for coupling the shaped charge120within a shaped charge holder20of a positioning device10/110. In an embodiment, at least one of the first wall342and the second wall344includes a groove/depression352circumferentially extending around the side wall340. The groove352extends inwardly from the side wall340of the case310towards the cavity322. The groove (352may be configured to receive one or more retention mechanisms80of the positioning device10/110or the shaped charge holder20, thereby securedly fastening the shaped charge120to the positioning device10/110or the shaped charge holder20.

According to an aspect, the size of the shaped charge120may be of any size based on the needs of the application in which the shaped charge120is to be utilized. For example, the conical case310of the shaped charge120may be sized to receive from about 3 g to about 61 g of the explosive load324. As would be understood by one of ordinary skill in the art, the caliber/diameter of the liner326may be dimensioned based on the size of the conical case310and the explosive load324upon which the liner326will be disposed. Thus, even with the use of three (3) shaped charges in the positioning device10/110(i.e., a three-shot assembly), the arrangement of the shaped charges120in the positioning device10/110, in combination with adjusting the size of the shaped charges120, may provide the equivalent shot performance (and provide equivalent fluid flow) of a typical assembly/shot carrier having 4, 5, 6 shaped charges.

Embodiments of the disclosure are further associated with a perforating gun module200. The perforating gun module200includes a housing/sub assembly/one-part sub210formed from a preforged metal blank/shape. The housing210may include a length L1of less than about 12 inches, alternatively less than about 9 inches, alternatively less than about 8 inches. According to an aspect, the length of the housing210may be reduced because the perforating gun module200does not require the use of separate tandem sub adapters to connect or seal a plurality of perforating gun modules200.

The housing210includes a first housing end212, a second housing end214, and a chamber216extending from the first housing end212towards the second housing end214. The housing210may be configured with threads to facilitate the connection of a string of perforating gun modules200together. According to an aspect, an inner surface220of the housing210at the first housing end212includes a plurality of internal threads221a, while an outer/external surface224of the housing210includes a plurality of external threads221bat the second housing end214. A plurality of housings210may be rotatably connected to each other via the threads221,221b. A plurality of sealing mechanisms, such as o-rings270, may be used to seal the housing210of the perforating gun200from the contents of the housing of an adjacent perforating gun, as well as from the outside environment (fluid in the wellbore) from entering the chamber216.

As illustrated inFIG. 10, the first housing end212has a first width W1, the second housing end214has a second width W2, and the chamber216has an internal diameter ID. The second width W2may be less than the first width W1, and the internal diameter ID of the chamber216may be substantially the same as the second width W2. As illustrated inFIG. 9, for example, the second housing end214of the housing210of the perforating gun200may be rotatably secured within the first housing end212(i.e., in the chamber) of the housing of an adjacent perforating gun200′. According to an aspect, the second housing end214is configured to be secured within a chamber of an adjacent perforating gun assembly200′, and the first housing end212is configured to secure a second housing end of another adjacent perforating gun module.

According to an aspect, one or more positioning devices10/110may be secured in the chamber216of the housing210. The positioning device10/110may be configured substantially as described hereinabove and illustrated inFIGS. 1-5. Thus, for purposes of convenience, and not limitation, the features and functionality of the positioning device10/110are not repeated in detail herein below.

As illustrated inFIGS. 8-10and according to an aspect, the first end22of the positioning device110is adjacent the first housing end212. The rib160of the device110engages with an inner surface220of the housing210, within the chamber216, thereby preventing the device from moving upwardly or downwardly in the chamber216.

As illustrated inFIGS. 8-11, a plate70of the positioning device110helps to further secure the positioning device110in the housing210. The plate70includes a protrusion74extending from a peripheral edge72of the plate70. As illustrated inFIGS. 12A-12B, the protrusion74may be seated in a slot222formed in an inner surface220of the housing210.FIG. 7illustrates the slot extending from the first housing end212into the chamber216. The protrusion74of the plate70engages the slot222to secure the positioning device110within the perforating gun200and prevent unwanted rotation of the positioning device110, and thus the shaped charge holder20, within the perforating gun module200. As described hereinabove, upon detonation of the shaped charges120, the plate70and the shaped charge holder20is configured to capture debris resulting from detonation of the shaped charges120. The captured debris, the plate70and the shaped charge holder20forms a mass/resulting mass111(FIG. 13A) upon the detonation of the charges120. As seen inFIG. 13B, the resulting mass111is retained in the chamber216of the housing210. The resulting mass111includes shrapnel and debris created upon the detonation of the shaped charges, as well as any additional wires (e.g. through wire260) or components previously placed or housed in the housing210.

The housing210further includes a recess/mortise218extending from the second housing end214towards the chamber216. The recess218partially tapers from the second housing end214towards the chamber216and is configured to house the detonator head52of a detonator50of an adjacent positioning device110. As illustrated inFIG. 9, for example, the disk25of the positioning device110of an adjacent perforating gun200covers a portion of the recess218, thereby forming an isolation chamber280for the detonator head52. According to an aspect, when the housing210includes a length L1of less than about 8 inches, the recess218may include a length L2of less than about 2 inches.

A bulkhead assembly230may be positioned between the chamber216(i.e., adjacent the second end24of the positioning device110) and the recess218. According to an aspect, the bulkhead assembly230is a rotatable bulkhead assembly. Such bulkhead assemblies are described in U.S. Pat. No. 9,784,549, commonly owned and assigned to DynaEnergetics GmbH & Co KG, which is incorporated herein by reference in its entirety.

The bulkhead assembly includes a bulkhead body232having a first end233and a second end234. A metal contact plug/metal contact250is adjacent the first end233of the bulkhead body232and a downhole facing pin236extends from a second end234of the bulkhead body232. The perforating gun module200further includes a feed through wire260extending from the detonator50to the metal contact plug250via the line-out portion of the detonator head52. The metal contact plug250is configured to secure the feed through wire260to the first end233of the bulkhead assembly230. According to an aspect, the metal contact plug250provides electrical contact to the bulkhead assembly230, while the downhole facing pin236is configured to transfer an electrical signal from the bulkhead assembly230to a detonator50′ of the adjacent perforating gun module200′.

FIGS. 8-11illustrate a collar240secured within the recess218. The collar240is adjacent the second end234of the bulkhead assembly230. According to an aspect, the collar240includes external threads242(FIG. 10) configured for engaging with or being rotatably secured in the recess218of the housing210. When the collar240is secured in the recess218, the bulkhead assembly230is also thereby secured in the housing210.

As illustrated inFIGS. 15, 16A, 16B and 17, when a plurality/a string of perforating gun modules200are connected to each other, the ground bars90secured to the positioning devices110engage with the inner surface220housing210to provide a secure and reliable electrical ground contact from the detonator50′ (seeFIG. 9), and also contacts the second end portion214of the adjacent perforating gun modules200. The support members82of each of the positioning devices110of the perforating gun modules200may prevent movement of the ground bar90along the central Y-axis of the shaped charge holder20and help to facilitate the contact of the ground bar with the second end portion of the adjacent perforating gun module200′.

WhileFIGS. 15, 16A and 16Billustrate the perforating gun modules200each including one positioning device110, it is contemplated that perforating gun modules may be configured to receive more than one positioning device110, or the positioning device10of shaped charge holder20described hereinabove with respect toFIGS. 1-2.FIG. 17illustrates an embodiment in which the positioning device110ofFIG. 3is coupled to the positioning device10or a separate shaped charge holder20ofFIGS. 1-2and are coupled together and secured in a housing210of a perforating gun module200. As described hereinabove with respect toFIG. 11, the elongated cavity40of the separate shaped charge holder20′ is retains a detonation extender55. The detonation extender55extends from the elongated opening of the positioning device110into the elongated opening of the separate shaped charge holder20′. The detonation energy from the detonator50simultaneously activates the shaped charges120of the first set of shaped charges and activates the detonation extender55, and a detonation wave from the detonation extender55simultaneously activates the second set of shaped charges120′ retained in the shaped charge holder20′ or separate positioning device10.

Embodiments of the disclosure may further be associated with a method of making a perforating gun assembly including a positioning device. The method includes providing a positioning device formed from an injection molded, casted, or 3D printed plastic material or 3-D milled and cut from solid plastic bar stock. The positioning device may be configured substantially as illustrated inFIGS. 1-3. A housing for the perforating gun module is pre-forged from a solid material, such as a block of metal or machinable steel. The block of metal may have a cross-sectional that generally corresponds to the desired cross-sectional shape of the housing. For example, the block of metal may have a cylindrical shape if a cylindrical-shaped housing is desired. According to an aspect, the housing is machined from a solid bar of metal. This requires less metal removal during machining, as compared to typical CNC machining procedures where the body is not pre-forged to a certain shape before machining. This may reduce the time it takes to manufacture the housing and reduces the amount of metal scrap generated during the manufacturing process. The method further includes arranging the positioning device within a chamber of the housing so that the shaped charges are positioned in an XZ-plane, in an outward, radial arrangement, about a central Y-axis of the shaped charge holder.

Embodiments of the disclosure may further be associated with a method of perforating an underground formation in a wellbore using a perforating gun assembly. The method includes selecting/identifying a target shot area for the underground formation. The target shot area may be selected based on a plurality of parameters, such as the desired fluid flow from the formation into the wellbore. The perforating gun assembly includes one or more perforating gun modules including a positioning device having a plurality of shaped charges secured therein. The positioning device is positioned within the chamber of a housing of the module. The positioning device and perforating gun module are configured substantially as described hereinabove with respect to the figures. Thus, for purpose of convenience and not limitation, those features are not repeated here.

The positioning device includes a plurality of shaped charges secured therein. According to an aspect, three shaped charges are positioned in the positioning device. The shaped charges may be arranged in an XZ-plane, in an outward, radial arrangement, about a Y-axis of the shaped charge holder. According to an aspect, the shaped charges are specially designed so that the perforating jets formed upon detonation of the shaped charges has an at least partially altered geometry. At least one of the internal surfaces, the liner geometry and/or liner constituents, and the explosive load of the shaped charges may be modified to change the shape of a perforating jet formed upon detonation of the shaped charges. A detonator is positioned centrally within the shaped charge holder so that it is, or will be, adjacent the initiation points of the shaped charges.

The method further includes positioning the perforating gun assembly in the wellbore adjacent the formation and sending an initiation signal to the detonator. The detonator directly initiates the shaped charges so that they each form a perforating jet. The resulting perforation jets create perforating tunnels in the formation that have the aforementioned altered geometry that facilitates a flow rate or hydraulic fracturing that is equivalent to the flow rate or the hydraulic fracturing typically facilitated by another shaped charge of a different size or composition. The method further includes injecting a fluid into the wellbore to fracture the formation. As described hereinabove, the three shape charges may have a shot performance that is equivalent to that of a traditional shaped charge carrier including 2, 4, 5, 6 or more shaped charges. This may facilitate a cost-effective and efficient way of adjusting the optimal flow path for fluid in the target formation, without modifying the arrangement or quantity of the receptacles of the positioning device.

EXAMPLES

Various perforating gun assemblies, including positioning devices and shaped charges, were made and tested, according to the embodiments of the disclosure. The shaped charges where detonated, and the total average shot area entrance hole diameters presented in the examples shown in Table 1 are based on the minimum and maximum hole diameter formed by the perforation jet upon detonation of the shaped charges.

The shaped charges tested (the results of the tests being presented in Table 1), each included a substantially cylindrical/conical case, an explosive load contained in a cavity of the case, and a liner disposed adjacent the explosive load. Samples A-1, B-1, C-1, E-1 and D-1 were each 0.35 inch equal entrance hole shaped charges. In Sample A-1, two (2) shaped charges were arranged in a traditional charge carrier. In Sample B-1, three (3) shaped charges were arranged in a traditional charge carrier. Sample C-1, four (4) shaped charges were arranged in a traditional charge carrier. In Sample D-1, five (5) shaped charges were arranged in a traditional charge carrier. In Sample E-1, six (6) shaped charges were arranged in a traditional charge carrier. In each of Samples A-2, B-2, C-2, D-2 and E-2 three (3) shaped charges were arranged in a positioning device configured substantially as described hereinabove. The shaped charges in Sample A-2 were 0.30 inch equal entrance hole shaped charges, the shaped charges in Sample B-2 were 0.35 inch equal entrance hole shaped charges, the shaped charges in Sample C-2 were 0.40 inch equal entrance hole shaped charges, the shaped charges in Sample D-2 were 0.45 inch equal entrance hole shaped charges, and the shaped charges in Sample E-2 were 0.50 inch equal entrance hole shaped charges. Notably, by adjusting only the size of the three (3) shaped charges utilized in Samples A-2, B-2, C-2, D-2 and E-2 and therefore the effective size of the entrance hole generated by the shaped charges in each positioning device, the assembly was able to generate total open areas/open surface areas similar to the total open areas of the traditional charge carriers including 2 shaped charges (Sample A-1), 3 shaped charges (Sample B-1), 4 shaped charges (Sample C-1), 5 shaped charges (Sample D-1) and 6 shaped charges (Sample E-2).

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 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 variations in these ranges will suggest themselves to a practitioner having ordinary skill in the art and, where not already dedicated to the public, the appended claims should cover those variations.

Advances in science and technology may make equivalents and substitutions possible that are not now contemplated by reason of the imprecision of language; these variations should be covered by the appended claims. This written description uses examples to disclose the method, machine and computer-readable medium, including the best mode, and also to enable any person of ordinary skill in the art to practice these, including making and using any devices or systems and performing any incorporated methods. The patentable scope thereof is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.