CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Application No. 63/001,772 filed March 30, 2020, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] In a high-density perforating gun, charge tubes may bow or bend inside the gun housing due to the weight of shaped charges mounted in the charge tube. This alters the distance between each shaped charge and the inner wall of the gun housing, which is a critical factor for the perforation performance of each shaped charge. To overcome this challenge, centralizers may be used to support the charge tube and help maintain a more constant distance between the shaped charges and the gun housing. However, conventional centralizers require space along the charge tube and typically decrease the overall shot density, and may also decrease the maximum open areas to flow in the perforating gun.

[0003] Accordingly, it may be desirable to develop a centralizer that can be used without reducing shot density. It is also desirable to develop a centralizer that maintains maximum open areas to flow.

BRIEF SUMMARY

[0004] An exemplary embodiment of a centralizer may include a centralizer body having a centralizer central axis and extending in a centralizer axial direction and a centralizer coupler provided at a first end of the centralizer body in the centralizer axial direction. The centralizer coupler may be configured to couple the centralizer body to the charge tube.

[0005] An exemplary embodiment of a charge tube assembly may include a charge tube and a first centralizer. The charge tube may include a charge tube body having a charge tube central axis and extending in a charge tube axial direction, a plurality of charge apertures provided in the charge tube body, and a first charge tube coupler provided proximate to a first charge aperture of the plurality of charge apertures. Each charge aperture of the plurality of charge apertures may be configured to receive a shaped charge. The first centralizer may include a first centralizer body having a first centralizer central axis and extending in a first centralizer axial direction and a first centralizer coupler provided at a first end of the first centralizer body in the first centralizer axial direction. The first charge tube coupler may be coupled with the first centralizer coupler.

[0006] An exemplary embodiment of a perforating gun may include a housing, a charge tube, a first centralizer. The housing may have a housing central axis and extend in a housing axial direction. The charge tube may be provided within the housing and may include a charge tube body having a charge tube central axis and extending in a charge tube axial direction, a plurality of charge apertures provided in the charge tube body, a plurality of shaped charges, each shaped charge of the plurality of shaped charges being provided in a charge aperture of the plurality of charge apertures, and a first charge tube coupler provided proximate to a first charge aperture of the plurality of charge apertures. The first centralizer may include a first centralizer body having a first centralizer central axis and extending in a first centralizer axial direction and a first centralizer coupler provided at a first end of the first centralizer body in the first centralizer axial direction. The first charge tube coupler may be coupled with the first centralizer coupler.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0007] A more particular description will be rendered by reference to exemplary embodiments that are illustrated in the accompanying figures. Understanding that these drawings depict exemplary embodiments and do not limit the scope of this disclosure, the exemplary embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0008] FIG. 1 is a perspective view of a centralizer according to an exemplary embodiment; [0009] FIG. 2 is an axial view of a centralizer according to an exemplary embodiment;

[0010] FIG. 3 is a side view of a centralizer according to an exemplary embodiment;

[0011] FIG. 4 is a perspective view of a charge tube and centralizer according to an exemplary embodiment;

[0012] FIG. 5 is an axial view of a charge tube according to an exemplary embodiment; [0013] FIG. 6 is an enlarged perspective view of a charge tube according to an exemplary embodiment;

[0014] FIG. 7 is a perspective view of a charge aperture according to an exemplary embodiment; [0015] FIG. 8 is a schematic cross section of a centralizer coupler and a charge tube coupler according to an exemplary embodiment;

[0016] FIG. 9 is a schematic cross section of a centralizer coupler and a charge tube coupler according to an exemplary embodiment;

[0017] FIG. 10 is a view showing an exemplary embodiment of a centralizer coupler coupled to a first slot;

[0018] FIG. 11 is a view showing an exemplary embodiment of a centralizer coupler coupled to a first slot;

[0019] FIG. 12 is a schematic cross section of a centralizer coupler and a charge tube coupler according to an exemplary embodiment;

[0020] FIG. 13 is a schematic cross section of a centralizer coupler and a charge tube coupler according to an exemplary embodiment;

[0021] FIG. 14 is a schematic cross section of a centralizer coupler and a charge tube coupler according to an exemplary embodiment;

[0022] FIG. 15 is a cutaway perspective view of a perforating gun according to an exemplary embodiment;

[0023] FIG. 16 is an axial view of a perforating gun, charge tube, and centralizers according to an exemplary embodiment; and

[0024] FIG. 17 is an axial view of a perforating gun, charge tube, and centralizers according to an exemplary embodiment.

[0025] 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.

DETAILED DESCRIPTION

[0026] FIG. 1 through FIG. 3 illustrate an exemplary embodiment of a centralizer 102. As seen in FIG. 1, the centralizer 102 may include a centralizer body 104 and a centralizer coupler 110a. Referring to FIG. 1 and FIG. 2, the centralizer body 104 may have a centralizer central axis 202 and extend along the centralizer central axis 202 in a centralizer axial direction. In other words, a direction along the centralizer central axis 202 may be the centralizer axial direction. In an exemplary embodiment, the centralizer may be formed by cutting from a stock of steel tubing using a laser cutting. The steel tubing may be the same steel tubing used to make a charge tube 404, thereby reducing material costs.

[0027] The centralizer coupler 110a may be provided at a first end 106 of the centralizer body 104 in the charge tube axial direction. The centralizer coupler 110a may be configured to couple the centralizer body 104 to a charge tube as discussed in detail herein.

[0028] In an exemplary embodiment, the centralizer coupler 110a may be one of a plurality of centralizer couplers. In the exemplary embodiment shown in FIG. 1, for example, the centralizer 102 may include the centralizer coupler 110a and the centralizer coupler 110b. The centralizer coupler 110a and the centralizer coupler 110b are spaced apart around the circumference of the centralizer 102. In an exemplary embodiment, the centralizer coupler 110a and the centralizer coupler 110b may be equidistantly spaced around the circumference of the centralizer 102. For convenience, even if though there may be multiple centralizer couplers such as the centralizer coupler 110a and the 110b, the centralizer couplers may be collectively referred to as a singular centralizer coupler.

[0029] As see in FIG. 1 and FIG. 3, the centralizer coupler 110a may include a centralizer coupler leg 112 extending from the first end 106 of the centralizer body 104 in the centralizer axial direction. The centralizer coupler 110a may further include a centralizer coupler foot 114 provided at an end of the centralizer coupler leg 112 opposite the centralizer body 104. Referring to FIG. 2, the centralizer 102 may have a centralizer circumferential direction 204 relative to the centralizer central axis 202. As seen in FIG. 3, a dimension 302 of the centralizer coupler leg 112 in the centralizer circumferential direction 204 may be less than a dimension 304 of the centralizer coupler foot 114 in the centralizer circumferential direction 204. However, the disclosure is not limited to this, and, in an exemplary embodiment, the dimension 302 and the dimension 304 may be equal to each other.

[0030] In an exemplary embodiment, the difference between the dimension 302 and the dimension 304 creates an appearance that the centralizer coupler foot 114 “points” or “extends” either in a clockwise or counterclockwise direction with respect to the centralizer circumferential direction 204. For example, in the exemplary embodiment shown in FIG. 1 and FIG. 3, the centralizer coupler foot 114 points in the clockwise direction when viewed along the centralizer central axis 202 from the first end 106. However, it will be understood that the disclosure is not limited to this embodiment, and that the centralizer coupler foot 114 can also point in the counterclockwise direction. In another exemplary embodiment, the centralizer coupler foot 114 may point or extend from the centralizer coupler leg 112 in both the clockwise direction and the counterclockwise direction. Additionally, in an exemplary embodiment in which the dimension 302 and the dimension 304 are equal to each other, it will be understood that the centralizer coupler foot 114 may not extend to either direction of the centralizer coupler leg 112.

[0031] In an exemplary embodiment where the centralizer 102 includes a plurality of centralizer couplers, such as the centralizer coupler 110a and the centralizer coupler 110b, each coupler may be shaped similarly. However, it will be understood that the disclosure is not limited to an embodiment in which each centralizer coupler is the same shape. For example, centralizer couplers may have different shapes so as to ensure a particular alignment of the centralizer when coupling to a charge tube.

[0032] As further seen in FIG. 1 and FIG. 3, the centralizer body 104 may include a concave portion 306 provided at the first end 106 of the centralizer body 104. The concave portion 306 may be contoured such that it sits flush against a charge tube outer surface 506 (see FIG. 16). Additionally, the centralizer body 104 may include a convex portion 308 provided at a second end 108 of the centralizer body 104. In an exemplary embodiment, the convex portion 308 may have a curvature that is substantially equal to a curvature of an interior surface of a housing 1504 (see FIG. 16).

[0033] FIG. 4 shows an exemplary embodiment of a charge tube assembly 402a. The charge tube assembly 402a may include a charge tube 404, a first centralizer 408, a second centralizer 410, a third centralizer 412, a first end plate 416, and a second end plate 418.

[0034] Referring to FIG. 4 and FIG. 5, the charge tube 404 may include a charge tube body 406 having a charge tube central axis 502 and extending in a charge tube axial direction. The charge tube 404 may further include a plurality of charge apertures, such as a charge aperture 414a, a charge aperture 414b, a charge aperture 414c, and a charge aperture 414d. Each charge aperture may be configured to receive a shaped charge. It will be understood that the charge apertures shown in FIG. 4 and FIG. 5, for example, as 414a, 414b, 414c, and 414d are labelled for illustrative purposes only, and that the plurality of charge apertures does not require these four specific charge apertures; the plurality of charge apertures may include less or more than the specifically labelled charge apertures shown in FIG. 4. [0035] In an exemplary embodiment, the first centralizer 408, the second centralizer 410, and the third centralizer 412 may be structured similarly to the first centralizer 408 described above with reference to FIG. 1, FIG. 2, and FIG. 3 and may have similar constituent parts.

[0036] In an exemplary embodiment, the first end plate 416 may be provided at a first end of the charge tube 404, and the second end plate 418 may be provided at a second end of the charge tube 404. The first end plate 416 and the second end plate 418 may be respectively secured to the charge tube 404 via a snaps, screws, fasteners, or other suitable coupling mechanism. The first end plate 416 and the second end plate 418 may help to support the ends of the charge tube 404 and prevent bowing caused by gravity.

[0037] In an exemplary embodiment, the charge tube 404 may include one or more charge aperture couplers provided proximate to one or more charge apertures of the plurality of charge apertures. For example, as seen in FIG. 6, an exemplary embodiment of the charge tube 404 may include a first charge aperture 602, a second charge aperture 604, and a third charge aperture 606. The charge tube 404 may further include a first charge tube coupler 608 proximate to the first charge aperture 602, a second charge tube coupler 610 proximate to the second charge aperture 604 and a third charge tube coupler 612 proximate to the third charge aperture 606. The first charge tube coupler 608, the second charge tube coupler 610, and the third charge tube coupler 612 may be configured to couple with the respective centralizer couplers of the first centralizer 408, the second centralizer 410, and the third centralizer 412. For example, FIG. 4 shows an exemplary embodiment wherein the centralizer couplers (not seen in FIG. 4) of the first centralizer 408, the second centralizer 410, and the third centralizer 412 are respectively coupled with the first charge tube coupler 608, the second charge tube coupler 610, and the third charge tube coupler 612 (not seen in FIG. 4), thereby coupling the first centralizer 408, the second centralizer 410, and the third centralizer 412 to the charge tube body 406. Referring back to FIG. 6, the first charge tube coupler 608, the second charge tube coupler 610, and the third charge tube coupler 612 may be formed as slots formed through the charge tube body 406. However, it will be understood that the charge tube couplers are not limited to this configuration, and that they may take any form that may couple with the centralizer coupler.

[0038] As described above, the singular term “centralizer coupler” may include one or more distinct structures provided on the centralizer 102, such as the centralizer coupler 110a and the centralizer coupler 110b. Similarly, as seen in FIG. 7, the singular term “charge tube coupler” may include one or more distinct structures provided on the charge tube body 406. In an exemplary embodiment shown in FIG. 7, for example, the first charge tube coupler 608 may include a first slot 704 and a second slot 706 provided proximate to the first charge aperture 602. In an exemplary embodiment, the first charge tube coupler 608 may include a number of slots equal to a number of centralizer coupler feet 114 provided on the centralizer 102, and the slots may be spaced around the circumference of the first charge aperture 602 similarly to the spacing of the centralizer coupler feet on the centralizer 102.

[0039] As further seen in FIG. 7, the first slot 704 may include an inner edge 708, and the second slot 706 may include an inner edge 710. In an exemplary embodiment, first slot 704 may be positioned proximate to the first charge aperture 602 such that a distance 712 between a center 702 of the first charge aperture 602 and the inner edge 708 of the first slot 704 may be equal to or less than an inner radius of the first centralizer 408. In another exemplary embodiment, the second slot 706 may be positioned proximate to the first charge aperture 602 such that a distance 714 between the center 702 of the first charge aperture 602 and the inner edge 710 of the second slot 706 may be equal to or less than the inner radius of the first centralizer 408. In another exemplary embodiment, the first slot 704 and the second slot 706 may be directly opposite each other with respect to the center 702 of the first charge aperture 602 such that the sum of the distance 712 and the distance 714 is equal to or less than an inner diameter of the first centralizer 408. In a further exemplary embodiment, a maximum diameter of the first charge aperture 602 may be smaller than an inner diameter of the first centralizer 408.

[0040] These dimensions may help to ensure that the structure of the first centralizer 408 remains clear of a shaped charge placed within the first charge aperture 602, and therefore does not interfere with the activation of the shaped charge. Thus, according to an exemplary embodiment, the centralizers will be complementary to the shaped charges, and it will not be necessary to eliminate shaped charges in a portion of the charge tube in order to employ a centralizer structure. Therefore, the weight of the charge tube can be fully supported without having to reduce overall charge density.

[0041] FIG. 8 and FIG. 9 are schematic cross-sections that illustrate an exemplary embodiment of coupling the first centralizer 408 to the charge tube body 406. FIG. 8 shows that the first centralizer 408 has been positioned proximate to the first charge aperture 602 such that the centralizer coupler 110a protrudes through the first slot 704 and the centralizer coupler 110b protrudes through the second slot 706.

[0042] In FIG. 9, the centralizer coupler 110a and the centralizer coupler 110b have been bent back in a direction toward an inner surface 902 of the charge tube body 406. This may be achieved, for example, by inserting a tool through a nearby charge aperture to grip the centralizer coupler 110a or the centralizer coupler 110b and bending the centralizer coupler 110a or the centralizer coupler 110b. Once the centralizer coupler 110a and the centralizer coupler 110b have been bent, the first centralizer 408 is prevented from pulling away from the charge tube body 406 because the centralizer coupler 110a and the centralizer coupler 110b would abut the inner surface 902 of the charge tube body 406.

[0043] It will be understood that, in an exemplary embodiment, it may not be necessary to bend the centralizer coupler 110a and the centralizer coupler 110b to a full 90 degrees as shown in FIG. 9. Instead, it is sufficient to merely bend the centralizer coupler 110a and the centralizer coupler 110b enough that the first centralizer 408 cannot be removed from the charge tube body 406. For example, FIG. 10 shows an exemplary embodiment in which the centralizer coupler 110a is only partially bent back towards the charge tube body 406. Alternatively, FIG. 11 shows an exemplary embodiment in which the centralizer coupler 110a is bent around an axis normal to the charge tube body 406.

[0044] FIG. 12, FIG. 13, and FIG. 14 are schematic cross-sections that illustrate another exemplary embodiment of coupling the first centralizer 408 to the charge tube body 406. FIG. 12 shows the centralizer coupler foot 114 of the first centralizer 408 proximate to the first slot 704 of the charge tube body 406. For simplicity of illustration, the centralizer body 104 of the first centralizer 408 has been substantially omitted from the drawings, and only the first end 106, the centralizer coupler leg 112, and the centralizer coupler foot 114 are shown.

[0045] As can be seen from FIG. 12, a dimension 1204 of the first slot 704 in the centralizer circumferential direction 204 may be larger than the dimension 304 of the centralizer coupler foot 114 in the centralizer circumferential direction 204. In this way, the centralizer coupler foot 114 may be insertable through the first slot 704 in the centralizer axial direction 1202. [0046] In FIG. 13, the centralizer coupler foot 114 has been inserted through the first slot 704. In FIG. 14, the first centralizer 408 has been rotated in the centralizer circumferential direction 204 such that the charge tube body 406 is interposed between the centralizer coupler foot 114 and the first end 106 of the first centralizer 408 in the centralizer axial direction 1202. This arrangement may help to keep the first centralizer 408 securely coupled to the charge tube body 406, as the centralizer coupler foot 114 will abut with the charge tube body 406 is the first centralizer 408 is pulled away from the charge tube body 406.

[0047] In exemplary embodiments where the centralizer coupler includes a plurality of centralizer coupler feet and the charge tube coupler includes a plurality of slots, it will be understood that the centralizer coupler feet and the slots may be aligned such that they may each be simultaneously coupled as illustrated in FIG. 12, FIG. 13, and FIG. 14.

[0048] FIG. 15 shows an exemplary embodiment of a perforating gun 1502. The perforating gun 1502 may include a housing 1504 and the charge tube assembly 402a provided within the housing. The charge tube assembly 402a may include the charge tube 404 and centralizers as described in detail above. A plurality of shaped charges, such as a shaped charge 1506a, shaped charge 1506b, shaped charge 1506c, shaped charge 1506d, and shaped charge 1506e, may be provided in the charge apertures of the charge tube 404. It will be understood that the shaped charges 1506a-1506e are labelled for illustration purposes only and are not intended to be limiting in any way. It will be understood that embodiments of the perforating gun 1502 may include more or less shaped charges than those specifically labelled in FIG. 15.

[0049] FIG. 16 shows an exemplary embodiment in which the concave portion 306 of the first centralizer 408 has a curvature that is substantially equal to a curvature of the charge tube outer surface 506. In this way, the first centralizer 408 may fit flush and securely against the charge tube 404, thereby firmly supporting the charge tube 404 and evenly distributing any load across the surface of the charge tube 404. This may help to prevent damage or distortion of the charge tube 404 during wellbore operations.

[0050] Additionally, FIG. 16 shows an exemplary embodiment in which the first centralizer 408, the second centralizer 410, and the third centralizer 412 are spaced substantially equidistantly around a charge tube circumferential direction 504 (See FIG. 5). For example, if the first centralizer 408 has a first centralizer central axis 1604, the second centralizer 410 has a second centralizer central axis 1606, and the third centralizer 412 has a third centralizer central axis 1608, then a first angle 1610 between the first centralizer central axis 1604 and the second centralizer central axis 1606, a second angle 1612 between the second centralizer central axis 1606 and the third centralizer central axis 1608, and a third angle 1614 between the third centralizer central axis 1608 and the first centralizer central axis 1604 may be substantially equal. This helps to ensure that the charge tube 404 may be adequately supported regardless of a rotational orientation within the wellbore.

[0051] For example, in FIG. 16, the first centralizer 408 is oriented toward the bottom of the housing 1504. With the force of gravity acting on the charge tube 404, the weight of the charge tube 404 and its shaped charges may cause it to bow downward. However, with the first centralizer 408 in place, one or more of an edge 1616 and an edge 1618 may contact an inner surface of the housing 1504 as the charge tube 404 bows, thereby supporting the charge tube 404 and preventing further bowing.

[0052] FIG. 17 shows an exemplary embodiment in which the perforating gun 1502 is oriented with the first centralizer 408 toward the top of the housing 1504. In this situation, as the charge tube 404 starts to bow due to gravity, one or more of an edge 1702 of the second centralizer 410 and an edge 1704 of the third centralizer 412 may contact the inner surface of the housing 1504, thereby supporting the charge tube 404 and preventing further bowing. Accordingly, it will be understood that, regardless of the orientation of the perforating gun 1502, one or more centralizers will be in position to contact the inner surface of the housing 1504 and support the charge tube 404.

[0053] Exemplary embodiments of the centralizers described above may provide several advantages. For example, as seen in FIG. 4 and FIG. 15, the centralizers fit directly over shaped charges and do not interfere with the perforation jet from a shaped charge. Therefore, the weight of the charge tube may be adequately supported without having to sacrifice space along the gun for positioning conventional centralizers. In other words, exemplary embodiments of the centralizers described above allow for a higher shot density for a given length of gun compared with conventional structures, and also allows for more open areas to flow for a gun of a given length. Additionally, embodiments of the centralizers may be quickly and easily coupled to a charge tube, thereby increasing user efficiency and productivity, and reducing the likelihood of errors in assembly the charge tube.

[0054] 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. [0055] 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.

[0056] 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.

[0057] 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."

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.