MULTIPLE POINT INITIATION FOR NON-AXISYMMETRIC SHAPED CHARGE

Abstract

A non-axisymmetric shaped charge including a casing, such as a non-axisymmetric shaped casing, and a liner housed therein, is generally described in which the casing includes multiple initiation points extending in a planar arrangement along an external surface of the casing. The non-axisymmetric shaped charge may include a plurality of guiding members positioned on the external surface. The non-axisymmetric shaped charge is capable of creating sufficient ballistic energy to uniformly collapse the liner.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application No. PCT/EP2016/069293 filed Aug. 12, 2016, which claims the benefit of U.S. Provisional Application No. 62/206,496 filed Aug. 18, 2015, each of which is incorporated herein by reference in its entirety.

FIELD

A non-axisymmetric shaped charge for use in a perforating gun, is generally described, wherein the non-axisymmetric shaped charge has multiple initiation points and a plurality of guiding members.

BACKGROUND

Perforating gun assemblies are used in many oilfield or gas well completions. In particular, the assemblies are used to generate holes in steel casing pipe/tubing and/or cement lining a well to gain access to the oil and/or gas deposit formation. These assemblies are usually cylindrical and include a detonating cord arranged within the interior of the assembly and connected to shaped charge perforators (or shaped charges) disposed therein. Typically, shaped charges are configured to focus ballistic energy onto a target to initiate production flow. Shaped charge design selection is also used to predict/simulate the flow of the oil and/or gas formation.

Shaped charges include conical or round shaped charges having a single point of initiation through a metal casing, which contains an explosive charge material, with or without a liner therein, that produces a perforating jet upon initiation. These shaped charges focus the entire ballistic energy onto a single point on the target, thereby producing a round perforation hole in the steel casing pipe or tubing and/or the formation. The ballistic energy creates a detonation wave that collapses the liner, thereby forming a forward-moving high velocity jet that travels through an open end of the casing housing the explosive charge. The jet pierces the perforating gun casing and/or the cement liner and forms a cylindrical tunnel in the surrounding target formation. Because round perforation holes have to be of a sufficient diameter in order to avoid bridging and screen out, holes of insufficient diameters leads to decreased flow which can cause production flow to be halted, which is costly.

Such conically-shaped charges are commercially available, and an example thereof is shown in FIG. 1. The shaped charge 10′ has an axisymmetric conical-shaped casing 20′ having a back wall portion 25′, a side wall portion 23′, and an open front portion 22′ forming a cavity or hollow interior 21′, and a liner 30′ disposed within the casing 20′. An explosive load 50′ is contained by the liner 30′, the explosive load 50′ being adjacent to and conforming to the interior shape of the casing 20′ as defined by the closed back wall portion 25′, the side wall portion 23′ and the open front portion 22′. The front portion 22′ is typically closed by the liner 30′. The external surface 62′ of the casing 20′ includes guiding members 60′ shaped as prongs and having a depression therein to guide/retain a detonating cord (not shown) towards an initiation point. While such conically-shaped charges typically incorporate a single initiation point, there have been solutions proposed in which the initiation point provides branches within the casing to more evenly distribute the initiation. As used herein, “axisymmetric” means that the shaped charge is symmetrical around the central axis y-y. For instance, for any given x-direction plane through the body, a distance between any point around the periphery is equidistant from the y-axis. Thus, as shown in FIG. 1, the distance L1 from the central axis y-y to one side of the liner 21′ is equal to a distance L2 to another position on the liner 21′, taken in the same x-direction plane.

Another objective of certain shaped charges is to assist in abandoning wells and/or oilfields. Well abandonment typically involves complicated procedures where the wellbore must be shut in and permanently sealed using cement. It is essential that the layers of sedimentary rock, in particular freshwater aquifers, are pressure isolated. Unwanted vertical channels or voids in a previously cemented wellbore annulus may exist. These channels can produce migration pathways for fluids or gas. Thus, an objective behind perforating with, for instance, a slot-shaped charge may not be to produce a circular hole in the casing or tubing pipe, but rather to produce a type of longitudinal slot or linear shaped slit or hole on the target pipe, particularly useful in performing the above-mentioned closing procedures.

While liners in the aforementioned conical-shaped charges have a v-shaped cross section, slot-shaped charges may also have a v-shaped cross-section, (linear, convex or concave), with the v-shape extending along a length of the charge. Since commercially available slot-shaped charges provide a side face or back end single initiation point, in addition to the aforementioned disadvantages associated with conically-shaped charges, the ballistic energy generated is often insufficient, resulting in a non-uniform collapse of the liner. When this occurs, the wells and/or oilfield may not be properly closed. As a result, groundwater contamination and/or threats to health, safety and the environment may occur.

In view of the disadvantages associated with currently available methods and devices for shaped charges, there is a need for a device and method that provides a more uniform distribution of ballistic energy. Due to the non-axisymmetric geometry of the linear shaped charges or slotted (i.e., slot-shaped) charges, including its inlay (liner), the collapse process of the metal-inlay (liner) and the jet-formation process behave considerably different in comparison to that of a conventional shaped charge. It is less favorable for the detonation shock waves to be induced at a single point of initiation for such slot-shaped charges, particularly including the v-shaped inlay/liner due to the geometry of these charges.

BRIEF DESCRIPTION

An apparatus and method of creating sufficient ballistic energy to uniformly collapse a liner in a non-axisymmetric shaped charge is generally described. The non-axisymmetric shaped charge, typically provided for use in a perforating gun, is generally described, wherein the non-axisymmetric shaped charge has multiple initiation points. The non-axisymmetric shaped charge generally includes a casing, such as a non-axisymmetric shaped casing, and the liner housed therein. According to an aspect, the casing includes multiple initiation points extending in a planar arrangement along an external surface of the casing and optionally a plurality of guiding members positioned on the external surface.

BRIEF DESCRIPTION OF THE FIGURES

A more particular description will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments thereof and are not therefore to be considered to be limiting of its scope, exemplary embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a cut-away perspective view of a shaped charge according to the prior art;

FIG. 2 is a is a cut-away perspective view of a shaped charge according to an embodiment;

FIG. 3 cross-sectional, elevation view of a non-axisymmetric shaped charge, according to an embodiment;

FIG. 4A is a cross-sectional, elevation view of the non-axisymmetric shaped charge of FIG. 3, illustrating the alignment of the detonating cord according to an embodiment;

FIG. 4B is a cross-sectional, elevation view of the non-axisymmetric shaped charge of FIG. 3, illustrating divots in the back wall according to an embodiment;

FIG. 5 is a bottom view of a non-axisymmetric shaped charge, illustrating guiding members and initiation points, according to an embodiment;

FIG. 6 is a perspective view of a perforating gun including a plurality of non-axisymmetric shaped charges positioned within a shaped charge carrier tube, according to an embodiment;

FIG. 7 is a perspective view of a perforating gun with its shaped charge carrier tube removed, according to an embodiment;

FIG. 8 is a perspective view of a shaped charge carrier tube including a pair of shaped charges, according to an embodiment;

FIG. 9 is a top view of the shaped charge carrier tube of FIG. 8, according to an embodiment;

FIG. 10 is a top view of a shaped charge carrier tube depicting an inwardly facing shaped charge, according to an embodiment; and

FIG. 11 is a flow chart depicting a method, according to an embodiment.

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.

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 “non-axisymmetric” means not axisymmetric as defined hereinabove, and includes non-circular and non-conical shapes. As an example, and with reference to the shaped charge found in FIG. 2, the distance between a point on the periphery of the body from the central axis y-y found at L3 is not equal to the distance found at L4. As used herein, the term “multiple” means more than one.

A non-axisymmetric shaped charge is generally described herein, having particular use in conjunction with a perforating gun assembly. In an embodiment, the non-axisymmetric shaped charge is configured for use with a perforating gun assembly, in particular for oilfield or gas well drilling or completions. The non-axisymmetric shaped charge provides multiple initiation points extending in a planar arrangement along an external surface of the non-axisymmetric shaped charge, which allows a liner to collapse more uniformly, thereby creating a substantially uniform and/or cleaner and/or deeper slot-shaped openings/perforations in a borewell casing and formation.

For purposes of illustrating features of the embodiments, a simple example will now be introduced and referenced throughout the disclosure. Those skilled in the art will recognize that this example is illustrative and not limiting, and is provided purely for explanatory purposes.

In an embodiment, and with particular reference to FIGS. 2 and 3, a non-axisymmetric shaped charge 10 is provided. In some embodiments, the non-axisymmetric shaped charge 10 is a slot shaped charge. The non-axisymmetric shaped charge 10 is illustrated having a casing 20 and a liner 30 housed within the casing 20. According to an aspect the casing 20 is a non-axisymmetric shaped casing 20. The casing 20 is shown including a plurality of side walls 23 (two side walls 23 shown), a back wall 25, and an open front portion 22. The casing 20 includes a hollow interior 21 bounded by the back wall 25 and side walls 23, within which the liner 30 is housed. As shown in FIG. 2, it is possible to configure the casing 20 with a positioning feature for alignment and placement of the shaped charge 10 within a carrier (as discussed in greater detail hereinbelow), such as a positioning groove 26 formed in an outer surface of opposing side walls 23. In an embodiment, the front portion 22 is open and the back wall 25 is at least partially closed. The liner 30 may be arranged within the hollow interior 21 in a manner configured to close the front portion 22. In an embodiment, the liner 30 is made of a material selected based on the target to be penetrated, and may be made of powdered metal and/or metal alloys held together by a percentage of binder materials. The powdered metal and/or metal alloy forming the liner 30 may include at least one of copper, tin, tungsten, lead, nickel, bronze, molybdenum or combinations thereof. In some embodiments, the liner 30 is made of a formed solid metal sheet, rather than compressed powdered metal and/or metal alloys. In another embodiment, the liner 30 is made of a non-metal material, such as glass, cement, high-density composite or plastic.

In accordance with the embodiment illustrated in FIG. 3, an explosive load 50 may be disposed within the hollow interior 21. The liner 30 may be positioned to enclose, encase or otherwise cover the explosive load 50 between the liner 30 and the back wall 25. In other words, the explosive load 50 may be enclosed, encased or positioned between the liner 30 and the back wall portion 25 in such a manner that it is secured within the casing 20. In some embodiments, the explosive load 50 is placed between a cavity formed by the side walls 23, the back wall 25 and the liner 30. In an embodiment, the side walls 23 and the back wall 25 may form a V-shaped cavity or cross-section within which the explosive load 50 is positioned. (See, for instance, FIG. 2.) The V-shaped cross-section extends along at least a portion of a length of the back wall portion 25, between two opposing side wall portions of the plurality of side walls 23. In some embodiments, the liner 30 may be pressed into and/or positioned on or over the explosive load. According to an embodiment, the liner 30 extends to the upper edge of the front portion 22 (FIG. 3), while in an alternative embodiment, the liner 30 does not extend all the way to the upper edge of the front portion 22 (FIG. 2). FIGS. 6 and 7 illustrate an embodiment in which the liner 30 is visible through the open front portion 22 of the non-axisymmetric casing 20. Since the liner 30 is not conically shaped as commonly found in a cylindrical shaped charge, care must be taken to properly place or seat the liner 30 within the casing 20 to substantially enclose the explosive load 50.

As illustrated in FIG. 3, the back wall 25 of the casing 20 includes an internal surface 63 and an external surface 62. The explosive load 50 is positioned in abutting contact with at least a portion of the internal surface 63. Multiple initiation points 40 are provided in the back wall 25 of the casing 20. In some embodiments, the multiple initiation points 40 are shaped like channels that begin at the internal surface 63 of the casing 20 and end at the external surface 62 of the casing 20. As illustrated in FIG. 3, the multiple initiation points 40 extend from the hollow interior 21 through the back wall 25 to the external surface 62 of the casing 20 and may be configured to receive and house some of the explosive load 50.

As illustrated in FIG. 3, a plurality of guiding members 60 may be positioned on at least a portion of the external surface 62 and proximate to at least one of the multiple initiation points 40. In an embodiment, the plurality of guiding members 60 may be disposed such that at least one of the plurality of guiding members 60 is positioned along one side or to the left of at least one of the multiple initiation points 40, while at least one other of the plurality of guiding members 60 is positioned along an opposing side or to the right. It is to be understood that while a guiding member 60 may be positioned on the right or left, re-positioning the non-axisymmetric casing 20 in a clockwise direction or a counter-clockwise direction could change the orientation such that the right is now the left, top, or bottom, and vice-versa. In an embodiment, the plurality of guiding members 60 may be provided to align a detonating cord 70 along the external surface 62 of the casing 20. As seen in this figure, the detonating cord 70 may be disposed between two of the plurality of guiding members 60. While the detonating cord 70 is depicted as flush with or adjacent to the initiation point 40, in some embodiments, the detonating cord 70 may be proximal to at least one of the multiple initiation points 40, but not in an abutting arrangement therewith. While FIG. 3 illustrates a plurality of guiding members 60 being provided on at least a portion of the external surface 62, it is to be understood that in some embodiments, guiding members 60 are not provided at all. As such, the detonating cord 70 is positioned along the external surface 62 and proximal or adjacent or flush with initiation points 40, being compressively and/or mechanically held in place by the casing 20.

Now referring to FIGS. 4A and 4B, and according to an embodiment, three multiple initiation points 40 are depicted. It is to be understood, however, that the non- axisymmetric shaped charge 10 may include two, three, four or more. In an embodiment, the multiple initiation points 40 extend radially from the hollow interior 21, within which an amount of the explosive load 50 is housed, to the external surface 62 of the casing 20. Depicted as channels/passageways, each of the multiple initiation points 40 may be completely filled with an amount of explosive load 50, at a distance measured from the hollow interior 21 to the external surface 62 of the casing 20. In some embodiments, the explosive load 50 may not fill each one of the multiple initiation points 40, but may completely fill most, but not all, of the multiple initiation points 40. In some embodiments, the explosive load may partially fill one of more of the multiple initiation points 40. In an embodiment, the length of each channel/passageway of each of the multiple initiation points 40 is substantially identical. In some embodiments the length of each channel/passageway of each of the multiple initiation points 40 varies. Each of the multiple initiation points 40 has a width that may be substantially identical to the width of adjacent initiation points 40. While the initiation points 40 depicted in FIGS. 4A-4B is three, it is to be understood that the number of initiation points 40 may be 2, 3, 4, or more.

Further, as illustrated in FIGS. 4A-4B, the detonating cord 70 may be positioned adjacent to the external surface 62 of the casing 20. The detonating cord is shown as being in abutting contact with the multiple initiation points 40. However, in some embodiments, the detonating cord 70 is adjacent to but not in abutting contact with the multiple initiation points 40. Further, as shown in FIG. 4B, in some embodiments, the multiple initiation points 40 do not extend from the hollow interior 21 completely through to the back wall 25 to the external surface 62 of the casing 20. Rather, in some embodiments, the back wall 25 includes divots 42, which form a part of the multiple initiation points 40. The divots 42 may be formed in at least one of the external surface 62 and the internal surface 63 of the back wall 25. In FIG. 4B, the divots 42 are shown as being formed in both the external surface 62 and/or the internal surface 63 of the back wall 25, thereby creating a thinner section of the back wall 25. In an embodiment, the divots 42 aid in retaining the explosive load 50 within the hollow interior 21 and may form a weakening point in the back wall 25 by way of providing a thinner section thereof. In this way, it is possible to make sure the explosive load 50 remains within the casing 20, while providing the weakening point, which facilitates ease of transmission of a shock wave to the explosive load 50 upon initiation of the detonating cord 70.

As depicted in at least FIGS. 4A and 4B, in some embodiments having a plurality of guiding members 60 positioned on the external surface 62 of the casing 20, each of the plurality of guiding members 60 is positioned generally above and/or generally below at least one of the multiple initiation points 40. In these embodiments, the plurality of guiding members 60 position and/or guide the detonating cord 70 along the external surface 62 of the casing 20. While the plurality of guiding members 60 are depicted as positioned in a substantially straight line on the external surface 62 of the casing 20, in some embodiments, at least some of the plurality of guiding members 60 are positioned offset from each other. (See, for example, the arrangement depicted and described in more detail with reference to FIG. 5.)

Further, FIGS. 4A and 4B depict the explosive load 50 housed in the casing 20 as partially filling a section of the hollow interior 21, the filled section extending from the back wall 25 to a position on the side walls 23 before the front portion 22. The amount of explosive load 50 selected may vary based on the size, shape and/or position of the liner housed in the hollow interior. In some embodiments, the amount of explosive load 50 housed within the hollow interior 21 may be selected based on a desired detonation force/wave. In some embodiments, the explosive load 50 may fill the entire hollow interior 21. In some embodiments, the explosive load 50 may fill about 25% to about 75% of the hollow interior 21.

FIG. 5 illustrates a view of the external surface 62 of the casing 20. As depicted in the figure, the multiple initiation points 40 may be oriented in a substantially linear configuration/fashion with respect to each other, such as along a vertical (Y) axis, along the external surface 62 of the casing 20. According to an aspect, the multiple initiation points 40 may extend between the external surface 62 and an internal surface 63 of the back wall portion 65. As depicted in FIG. 5, each of the multiple initiation points 40 may be positioned equidistantly from adjacent initiation points 40. In some embodiments, (not shown) the multiple initiation points 40 are not positioned equidistantly from each adjacent initiation point 40 and may be spaced apart from each other by varying distances. In FIG. 5, each of the multiple initiation points 40 is shown having a cross-sectional shape that is circular. However, it is to be understood that some initiation points 40 may have a cross-sectional shape that is one of a symmetrical, semi-symmetrical and asymmetrical shape. For example, a symmetrical cross-section shape may include a square or rectangular shape. However, in some embodiments (not shown) the cross-sectional shape of the multiple initiation points 40 may be of any cross-sectional shape, such as, rectangular, square or any other shape suitable for housing and/or communicating initiation of a detonating cord 70 and transmission of the thus-initiated shock to the explosive load 50.

Further, in FIG. 5 and in an embodiment having a plurality of guiding members 60, each of the plurality of guiding members 60 is positioned at least somewhat proximal to at least one of the multiple initiation points 40. While the plurality of guiding members 60 are each shown in the shape of a rhomboid, it is to be understood that the plurality of guiding members 60 may be of any shape and size sufficient to guide/position and/or retain a detonating cord 70 across the external surface 62 of the back wall 25 of the casing 20 and across the multiple initiation points 40. In some embodiments, the arrangement of the plurality of guiding members 60 is directed/arranged in a slanted direction in such a way that it facilitates and is capable of positioning the detonating cord 70 in a substantially helical pattern. In some embodiments, the plurality of guiding members 60 are spaced apart from each other, forming a gap 64 of sufficient size to receive and/or align the detonating cord 70 along the external surface 62 of the non-axisymmetric shaped casing 20. As depicted in FIG. 5 and in some embodiments, each of the plurality of guiding members 60 may be oriented or aligned vertically and/or horizontally with an adjacent guiding member 60. The positioning and frequency and/or quantity of each of the plurality of guiding members 60 may be selected to guide the detonating cord 70 across/over one or more of the multiple initiation points 40. While the plurality of guiding members 60 depicted in FIG. 5 is shown as four, it is to be understood that the number of guiding members 60 may be 2, 3, 4, or more, when used.

FIGS. 6-10 illustrate the non-axisymmetric shaped charges 10 positioned within various shaped charge carrier tubes 92, 92′. The charges 10 may be secured and/or retained within the tubes 92, 92′ by various means, such as for example, a retention clip, and groove and tongue connections. Referring now to FIG. 6, an illustrative example in which the non-axisymmetric shaped charges 10 are positioned within a shaped charge carrier tube 92 having retention clips, the shaped charges 10 partially extending from a perforating gun 90, is shown. The perforating gun 90 includes the shaped charge carrier tube 92 disposed within a bore 96 of the perforating gun 90. The perforating gun 90 further includes a plurality of non-axisymmetric shaped charges 10, substantially as described herein and shown in the figures, disposed within the shaped charge carrier tube 92. While the perforating gun 90 is shown having three non-axisymmetric shaped charges 10, it is to be understood that the perforating gun 90 may include any number of non-axisymmetric shaped charges 10. The plurality of non-axisymmetric shaped charges 10 may be positioned in the shaped charge carrier tube 92 in an outwardly facing helical arrangement as depicted. Although not shown in FIG. 6, the detonating cord 70 may be positioned behind the back wall 25 of the casing 20. When present, the plurality of guiding members 60 may be used to position and/or align the detonating cord 70.

FIG. 7 shows the shaped charge carrier tube 92 situated outside of the perforating gun 90, prior to insertion into the perforating gun 90. The shaped charge carrier tube 92 includes several openings 95, each configured for receiving one of the shaped charges 10 positioned therein. As shown herein, the plurality of non-axisymmetric shaped charges 10 are positioned in the shaped charge carrier tube 92 in an outwardly facing helical arrangement, and the casing 20 extends from one side of the carrier tube 92 to the opposite side. In some embodiments, the plurality of non-axisymmetric shaped charges 10 is mounted in a helical fashion around the shaped charge carrier tube 92, and is coupled by a detonating cord 70.

Referring now to the embodiment illustrated in FIGS. 8 and 9, the shaped charge carrier tube 92′ is depicted including a pair of the plurality of non-axisymmetric shaped charges 10 positioned in the shaped charge carrier tube 92′ in an abutting external surface to external surface, or back-to-back, arrangement. As shown herein, the pairs of the plurality of non-axisymmetric shaped charges 10 are positioned in the shaped charge carrier tube 92′ in an outwardly facing helical arrangement, and the shaped charges 10 are secured and/or retained within the shaped charge carrier tube 92′ by groove and tongue connections. As shown, pairs of the openings 95 are also essentially aligned to accommodate placement of the shaped charges 10 in the back-to-back arrangement. FIG. 9 shows the detonating cord 70 positioned within the shaped charge carrier tube 92′, and the detonating cord 70 is shared by the pair of non-axisymmetric shaped charges 10.

In an embodiment, the guiding members 60 create a space between the external surfaces of the abutting shaped charges, within which the detonating cord 70 is positioned. In an embodiment, the detonating cord 70 is arranged within a bore of the shaped charge carrier tube 92′. According to an aspect, the detonating cord 70 is positioned between the abutting external surfaces 62 of each of the pairs of plurality of non-axisymmetric shaped charges 10. The detonating cord 70 may further be positioned within the gap 64 disposed between any pair of the plurality of guiding members 60 (see FIG. 5). In some embodiments, the detonating cord 70 is centrally located within the bore of the shaped charge carrier tube 92′. In an alternate embodiment, the detonating cord 70 is arranged exteriorly to the shaped charge carrier tube 92/92′ (not shown).

FIG. 10 depicts an embodiment in which one of the shaped charges 10 of a pair of the shaped charges is positioned within the carrier tube 92′ in an inwardly facing arrangement, without positioning the other of the pair of shaped charges, and leaving that opposing opening 95 blank. Thus, the front portion 22 of the casing 20 extends towards the inside of the carrier tube 92′, while the back wall portion 25 slightly extends (in an embodiment) from the opening 95. In this arrangement, the detonating cord 70 may be positioned external to the carrier tube 92′, and upon detonation, the shaped charge 10 would fire through that opposite opening 95, shown directionally by the broken arrows. In such an arrangement, the jet formed by discharge of the shaped charge has more distance to form itself prior to reaching the perforating gun casing.

Turning now to FIG. 11, a flow chart is provided that illustrates a method of forming a non-axisymmetric shaped charge. In an embodiment, the method includes forming a non-axisymmetric casing 20 having a hollow interior 21 defined by a front portion 22, a plurality of side wall portions 23, and a back wall portion 25, wherein the front portion 22 is open; forming multiple initiation points 40 in the back wall portion 25 of the casing, the multiple initiation points 40 extending in a planar arrangement along the external surface 62 of the back wall portion 25; delivering an explosive load 50 into the hollow interior 21 of the casing 20; and restraining the explosive load 50 within the hollow interior 21 by positioning a liner 30 within the open front portion 22 of the casing 20. The method may optionally include forming and positioning a plurality of guiding members 60 on an external surface 62 of the back wall portion 25 of the casing 20.

According to an aspect, a method of detonating/initiating a non-axisymmetric shaped charge 10, substantially as defined hereinabove, is provided. Initiation of the non-axisymmetric shaped charge 10 may be non-simultaneous. In an embodiment, initiation of the non-axisymmetric shaped charge 10 occurs via a detonation shock propagating substantially simultaneously across the multiple initiation points 40. In accordance with yet another embodiment, initiation of the non-axisymmetric shaped charge 10 occurs via a detonation shock propagating with at least a minor time delay across the multiple initiation points 40 caused by the high velocity of the detonating cord, thus initiation of the non-axisymmetric shaped charge 10 is substantially non-simultaneous.

The components and methods illustrated are not limited to the specific embodiments described herein, but rather, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the non-axisymmetric shaped charge, perforating gun incorporating the non-axisymmetric shaped charge and method of forming the non-axisymmetric shaped charge include such modifications and variations. Further, steps described in the method may be utilized independently and separately from other steps described herein.

While the non-axisymmetric shaped charge and method of forming the non-axisymmetric shaped charge have been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope contemplated. In addition, many modifications may be made to adapt a particular situation or material to the teachings found herein without departing from the essential scope thereof.

In this specification and the claims that follow, reference will be made to a number of terms that have the following meanings. The singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. 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,” 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 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 a non-axisymmetric shaped charge, perforating gun using such non-axisymmetric shaped charge, and a related method of using both, 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.

Claims

1. A non-axisymmetric shaped charge comprising:

a non-axisymmetric shaped casing having a hollow interior;

a liner housed within the non-axisymmetric shaped casing;

an explosive load disposed within the hollow interior; and

multiple initiation points extending in a planar arrangement along an external surface of the non-axisymmetric shaped casing.

2. The non-axisymmetric shaped charge of claim 1, wherein the non-axisymmetric shaped casing is further defined by a front portion, a plurality of side wall portions and a back wall portion, wherein the front portion is open.

3. The non-axisymmetric shaped charge of claim 2, wherein the explosive load is enclosed, encased or positioned between the liner and the back wall portion.

4. The non-axisymmetric shaped charge of claim 2 wherein the liner has a V-shaped cross-section that extends along at least a portion of a length of the back wall portion between two opposing side wall portions of the plurality of side wall portions.

5. The non-axisymmetric shaped charge of claim 1, wherein the multiple initiation points are arranged in a substantially linear configuration with respect to each other.

6. The non-axisymmetric shaped charge of claim 1, wherein the multiple initiation points comprises three or more initiation points.

7. The non-axisymmetric shaped charge of claim 1, further comprising a plurality of guiding members positioned on the external surface.

8. The non-axisymmetric shaped charge of claim 7, wherein the plurality of guiding members are spaced apart from each other.

9. The non-axisymmetric shaped charge of claim 7, wherein the plurality of guiding members are spaced apart from each other providing a gap configured for aligning a detonating cord along the external surface of the non-axisymmetric shaped casing.

10. The non-axisymmetric shaped charge of claim 7, wherein the plurality of guiding members are arranged in a slanted direction to position a detonating cord in a substantially helical pattern.

11. A perforating gun comprising:

a shaped charge carrier tube having openings; and

a plurality of non-axisymmetric shaped charges, wherein each of the plurality of shaped charges are positioned within each of the openings, further wherein each of the plurality of non-axisymmetric shaped charges comprises: a non-axisymmetric shaped casing having a hollow interior; a liner housed within the non-axisymmetric shaped casing; an explosive load disposed within the hollow interior; and multiple initiation points extending in a planar arrangement along an external surface of the non-axisymmetric shaped casing.

12. The perforating gun of claim 11, wherein each of the plurality of non-axisymmetric shaped charges further comprise a plurality of guiding members positioned on the external surface.

13. The perforating gun of claim 11, wherein the non-axisymmetric shaped casing is further defined by a front portion, a plurality of side wall portions and a back wall portion, wherein the front portion is open.

14. The perforating gun of claim 11, wherein the plurality of non-axisymmetric shaped charges are positioned in the shaped charge carrier tube in an outwardly facing helical arrangement.

15. The perforating gun of claim 11, wherein at least a pair of the plurality of non-axisymmetric shaped charges are positioned in the shaped charge carrier tube in an abutting external surface to external surface arrangement.

16. The perforating gun of claim 12, further comprising a detonating cord, wherein the detonating cord is arranged exteriorly to the shaped charge carrier tube.

17. The perforating gun of claim 12, further comprising a detonating cord, wherein the detonating cord is arranged within a bore of the shaped charge carrier tube and positioned within a gap disposed between the plurality of guiding members.

18. The perforating gun of claim 15, further comprising a detonating cord arranged within a bore of the shaped charge carrier tube and positioned between the abutting external surfaces of each of the pairs of the plurality of non-axisymmetric shaped charges.

19. A method of forming a non-axisymmetric shaped charge comprising:

forming a non-axisymmetric shaped casing having a hollow interior defined by a front portion, a plurality of side wall portions, and a back wall portion, wherein the front portion is open;

forming multiple initiation points in the back wall portion of the non-axisymmetric shaped casing, the multiple initiation points extending in a planar arrangement along an external surface of the back wall portion; delivering an explosive load into the hollow interior of the non-axisymmetric shaped casing; and

restraining the explosive load within the hollow interior by positioning a liner within the open front portion of the non-axisymmetric shaped casing.

20. The method of claim 19, further comprising forming and positioning a plurality of guiding members on the external surface of the back wall portion of the non-axisymmetric shaped casing.