WO2022122742A2

WO2022122742A2 - Equal entry hole perforating gun system with position optimized shaped charges

Info

Publication number: WO2022122742A2
Application number: PCT/EP2021/084619
Authority: WO
Inventors: Francisco MONTENEGRO
Original assignee: DynaEnergetics Europe GmbH
Priority date: 2020-12-09
Filing date: 2021-12-07
Publication date: 2022-06-16
Also published as: WO2022122742A3

Abstract

According to some embodiments, a device, a system, and a method of producing equal entry holes in a wellbore is presented. In some embodiments, at least two shaped charges, which each may be configured to produce a different width of perforating jet, may be oriented at different wellbore phasing angles. By selecting the orientation and width of the different perforating jets of the shaped charges across different clearance distances when the perforating gun is decentralized in the wellbore, equal entry holes may be formed in the wellbore. For example, a shaped charge with a wider perforating jet may be selected to be oriented across a longer clearance distance, while a shaped charge with a narrower perforating jet may be oriented across a shorter clearance distance. In some embodiments, the at least two shaped charges may use different shaped charge liners with different densities.

Description

EQUAL ENTRY HOLE PERFORATING GUN SYSTEM WITH POSITION OPTIMIZED SHAPED CHARGES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application No. 63/216,794 filed June 30, 2021 and United States Provisional Patent Application No. 63/122,994 filed December 9, 2020. The entire contents of each of the applications listed above are incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

[0002] Wellbore tools used in oil and gas operations, including perforating guns housing shaped charges, are often sent down a wellbore in tool strings connected together to reduce time and costs associated with the operation. Sub-assemblies may connect adjacent wellbore tools to one another to form the tool string.

[0003] Hydraulic fracturing is a commonly-used method for extracting oil and gas from geological hydrocarbon bearing formations, such as shale and other tight-rock formations. A typical hydraulic fracturing wellbore has long horizontal sections extending laterally inside the hydrocarbon bearing formations. Once the wellbore is established by placement of casing pipes after drilling, the casing is cemented to establish a hydraulic barrier between the different geological formations and the casing in the wellbore. After cementing, a train or string of multiple perforating gun assemblies may be lowered into the wellbore and positioned adjecting the hydrocarbon reservoir in the underground formation. Each perforating gun contains one or more shaped charges, aiming in a direction substantially perpendicular to the wellbore axis towards the formation. The shaped charges inside the perforating guns are initiated, and they form a perforation hole in the casing and a tunnel from the wellbore inside the hydrocarbon bearing formation. Next to the perforation, a hydraulic pressure is applied to the wellbore and towards the perforation tunnels on the geological formation. The hydraulic pressure produces cracks in the formation.

[0004] By placing a perforating gun with conventional shaped charges in a horizontal section of a wellbore, the hole sizes may have a high variation due to the varying clearances (i.e., the distance between the outside of the perforating gun and the inside wall of the wellbore casing). In particular, the diameter of the entry hole, i.e., the hole created in the wellbore casing or surface of the hydrocarbon bearing formation adjacent to the wellbore casing, may be highly variable due to varying clearances. For purposes of this disclosure, phrases such as, without limitation, “hole”, “entry hole”, “perforation hole”, and “entrance hole” refer to the entry hole, and a “size” of the hole is a diameter of the hole, unless expressly stated otherwise or as the context may make clear. In a horizontal gun well where the gun strings are typically lying on the low side (e.g. bottom) of the wellbore tubular, the gun diameter to casing inner surface clearance value may vary significantly, for example by as much as approximately 40 mm or 1.6 inches, depending on gun size, casing size, and casing grade. Generally speaking, for identical conventional shaped charges, shorter gun-to- wellbore clearances produce bigger holes, while higher gun-to-wellbore clearances produce smaller holes.

[0005] For establishing a uniform pressure buildup on a perforation location, it may be desirable or important for the entry holes to be as uniform as possible. Traditionally, this has been achieved by different methods, for example by centralizing the perforating gun string in the wellbore or by using specialized constant entry hole shaped charges, which produce a perforation hole with a low variation of hole size over a certain gun-to-wellbore clearance. Typical constant entry hole shaped charges, however, tend to sacrifice depth of penetration for their ability to produce a constant sized entry hole. Centralizing hardware may add to the expense and complexity of running a tool string downhole. Accordingly, there is a need for an improved system for providing multi-phasing equal entry holes when the perforating gun is decentralized within a horizontal wellbore. For example, the improved system may not require specialized constant entry hole shaped charges (but for example, might use conventional shaped charges) and/or may provide improved penetration compared to specialized constant entry hole shaped charges.

[0006] Another commonly used method has been to place a perforating gun, which has identical shaped charges all directed similarly, in the wellbore. The whole perforating gun may then be oriented inside the wellbore in the favored position. Most commonly-used systems direct the firing path of the shaped charges in the favored direction. Oriented systems normally have a favored/preferred shooting direction (e.g. upwards) to achieve a constant, predictable perforation hole size. In other words, all of the shaped charges typically would be oriented in approximately the same direction, in order to produce equal entry holes. With only one shooting direction, however, the orienting systems are limited in their potential uses.

[0007] Accordingly, there is a need for an orienting system that can provide a predictable, constant hole size for shaped charges firing at varying clearances (e.g. when the shaped charges are not all directed the same direction). Further, there is a need for an orienting system that can provide a predictable, constant hole size with the ability to shoot in more than one general direction.

BRIEF DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0008] According to an aspect, exemplary embodiments of the disclosure include a tool string, with one or more perforating guns. The tool string may be configured for use in a substantially horizontal wellbore casing. The tool string includes a first shaped charge and a second shaped charge. The second shaped charge is configured to form a wider perforating jet than the first shaped charge, while the first shaped charge and the second shaped charge are configured to be oriented at different wellbore phasing angles.

[0009] In another aspect, the exemplary embodiments include a perforating gun, which may be configured for use in a substantially horizontal wellbore casing. The perforating gun includes a first shaped charge and a second shaped charge. The second shaped charge is configured to form a wider perforating jet than the first shaped charge, while the first shaped charge and the second shaped charge are oriented at different phasing.

[0010] In a further aspect, the exemplary embodiments include a method of producing multi-phasing equal entry hole diameters in a horizontal wellbore casing. For example, the method embodiments may include the steps of providing a perforating gun or a tool string having a first shaped charge and a second shaped charge, positioning the perforating gun or tool string in a radially decentralized position within the horizontal wellbore, detonating the first shaped charge and the second shaped charge, and forming a first entry hole from the detonation of the first shaped charge and forming a second entry hole from the detonation of the second shaped charge. The second shaped charge is configured to form a wider perforating jet than the first shaped charge, and the first shaped charge and the second shaped charge are configured to be oriented at different wellbore phasing angles. The resulting first entry hole and second entry hole (after detonation) have a substantially equal entry hole diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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: [0012] FIG. l is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0013] FIG. 2 is a cross-sectional side view of an exemplary shaped charge, according to an embodiment.

[0014] FIG. 3 is a cross-sectional side view of an exemplary perforating gun, according to an embodiment;

[0015] FIG. 4 is a partial cross-sectional perspective view of the perforating gun shown in FIG. 3;

[0016] FIG. 5 is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0017] FIG. 6 is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0018] FIG. 7 is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0019] FIG. 8 is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0020] FIG. 9 is a cross-sectional front elevated view of an exemplary equal entry hole perforating gun system positioned in a wellbore, according to an embodiment;

[0021] FIG. 10 is a schematic perspective view of an exemplary equal entry hole perforating gun system shown as a wellbore tool string, according to an embodiment; and

[0022] FIG. 11 is a cross-sectional front view of the embodiment shown in FIG. 10.

[0023] 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 aid in understanding the features of the exemplary embodiments.

[0024] The headings used herein are for organizational purposes only and are not meant to limit the scope of the disclosure or the claims. To facilitate understanding, reference numerals have been used, where possible, to designate like elements common to the figures. DETAILED DESCRIPTION

[0025] Reference will now be made in detail to various exemplary 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. It is understood that reference to a particular “exemplary embodiment” of, e.g., a structure, assembly, component, configuration, method, etc. includes exemplary embodiments of, e.g., the associated features, subcomponents, method steps, etc. forming a part of the “exemplary embodiment”.

[0026] Exemplary embodiments will now be introduced according to FIGS. 1-11. The exemplary embodiments according to FIGS. 1-11 are illustrative and not limiting, and exemplary features may be referenced throughout this disclosure.

[0027] Disclosed embodiments may relate to devices, systems, and methods for producing multi-phase equal entry hole diameters in a horizontal wellbore casing, especially when the one or more perforating gun is disposed in a radially decentralized position (e.g. at the bottom) within the horizontal wellbore. In some embodiments, two, three, or four shaped charges may be disposed in a single perforating gun, each with a different wellbore phasing angle and/or phasing, and the shaped charges may be selected to be position optimized (e.g. each shaped charge is selected with a particular perforating jet based on its wellbore phasing angle (or phasing with respect to the gun) and the resulting clearance to the wellbore). For example, at least two of the shaped charges may be configured for use with respect to specific clearance/offset between the shaped charge and the wellbore, and configured to create equal entry holes despite different clearances therebetween (e.g. when the perforating gun and/or tool string is radially decentralized within the horizontal wellbore).

[0028] In some embodiments, two, three, four, or more shaped charges may be disposed in a tool string having at least one perforating gun. For example, the tool string may include one, two, three, four, or more perforating guns, and each perforating gun within the perforating gun string may have one, two, three, four, or more shaped charges. In some embodiments, the tool string may have only a single perforating gun, for example connected to one or more other wellbore tools, and the single perforating gun may have two, three, four, or more shaped charges. In some embodiments, the two, three, four, or more shaped charges may each have a different wellbore phasing angle and/or phasing, and each of the shaped charges may be configured or selected to create equal entry holes despite different clearances (e.g. when the tool string and/or perforating gun is radially decentralized within the horizontal wellbore). For example, each of the shaped charges may be configured or selected based on the wellbore phasing angle at which it will be used and/or the associated clearance distance between the shaped charge and the cased wellbore arising due to the wellbore phasing angle. Thus, different conventional shaped charges may be used at different wellbore phasing angles to produce equal entry holes, despite different clearances arising based on the differing wellbore phasing angles. For example, the conventional shaped charges may not be specialized constant entry hole shaped charges.

[0029] In some embodiments, at least two shaped charges, with each shaped charge being configured to produce a different width and/or penetration depth of perforating jet, may be oriented at different wellbore phasing angles within a perforating gun. By selecting the orientation and width of the different perforating jets of the shaped charges across different clearance distances when the perforating gun is decentralized in the wellbore, equal entry holes may be formed in the wellbore. For example, a shaped charge with a wider perforating jet may be selected to be oriented across a longer clearance distance, while a shaped charge with a narrower perforating jet may be oriented across a shorter clearance distance. FIGS. 1-9 show specific exemplary embodiments relating to a single perforating gun with a plurality of different shaped charges oriented at different wellbore phasing angles, which may be illustrative.

[0030] FIGS. 1, 3, 4, 5 illustrate an exemplary perforating gun 200 for use within a substantially horizontal wellbore casing, with FIGS. 1 and 5 showing the exemplary perforating gun 200 disposed within the horizontal wellbore. As used herein, “horizontal wellbore” may include any substantially horizontal wellbore, for example a wellbore that is angled beyond 45 degrees, beyond 60 degrees, beyond 75 degrees, or beyond 80 degrees from vertical (e.g. with vertical being parallel to gravity), or that is angled no more than 45 degrees, no more than 30 degrees, no more than 20 degrees, or no more than 10 degrees from flat horizontal (e.g. with flat horizontal being perpendicular to gravity). In these examples, the perforating gun 200 includes a first shaped charge 12 and a second shaped charge 10, with the first shaped charge 12 and the second shaped charge 10 being configured to be oriented at different wellbore phasing angles (e.g. having different phasing about the hardware/perforating gun, so that orientation of the gun within the well produces different clearances), and the second shaped charge 10 being configured to form a wider perforating jet than the first shaped charge 12. Generally, “phasing” means the angular distribution of shaped charges around the axis (e.g. a longitudinal central axis) of the perforating gun, for example the angular difference between successive perforating jets (directed out of the perforating gun by the shaped charges) and/or the resulting perforations/holes in the wellbore that are formed when the shaped charges are initiated in a cased wellbore.

[0031] In the context of this patent application, and with reference to FIG. 1, for example, “wellbore phasing angle” or “penetration angle” may relate to a situation when a perforating gun is decentralized (e.g. located on the bottom) within a cased horizontal wellbore, and refers to an orientation system wherein 0-degree wellbore phasing angle references the upward direction (e.g. opposite of gravity and/or corresponding to maximum clearance distance between the perforating gun and the cased wellbore), while 180-degree wellbore phasing angle references the downward direction (e.g. the direction of gravity and/or corresponding to minimum clearance distance between the perforating gun and the cased wellbore). Other wellbore phasing angles would be based on angular displacement/spacing relative to the 0- degree wellbore phasing angle, proceeding positively clockwise as shown in FIG. 1. In other embodiments, the term “wellbore phasing angle” may refer to a similar orientation system for a perforating gun which is centralized, for example with 0-degree wellbore phasing angle corresponding to the direction opposite of gravity, and 180-degree wellbore phasing angle corresponding to the direction of gravity. For example, “wellbore phasing angle” or “penetration angle” may refer to the orientation of the shaped charges and/or the penetration of the wellbore by the perforating jets of the shape charges with respect to a horizontal wellbore, with 180-degrees corresponding to the direction of gravity in the wellbore.

[0032] In FIG. 1, the perforating gun 200 is decentralized in the wellbore. In this configuration, the distance of the first shaped charge 12 from the wellbore casing 32 is substantially less than the distance of the second shaped charge 10 from the wellbore casing 32. The first shaped charge 12 fires across less clearance (e.g. the distance between the perforating gun 200 and the wellbore casing 32) than the second shaped charge 10. For example, when the perforating gun 200 is decentralized in horizontal wellbore as in FIG. 1, the first shaped charge 12 is directed across the minimum clearance between the perforating gun 200 and the wellbore casing 32, while the second shaped charge 10 is directed across the maximum clearance between the perforating gun 200 and the wellbore casing 32. In some embodiments, the first shaped charge 12 and the second shaped charge 10 may be angularly spaced apart by about 180 degrees (e.g. hardware phasing of 180 degrees). In FIG. 1, for example, the first shaped charge 12 has a 180-degree wellbore phasing angle, and the second shaped charge 10 has a 0-degree wellbore phasing angle. [0033] In some embodiments, the first shaped charge 12 and the second shaped charge 10 may each be configured to rotate about an axis 14 (which may correspond to a longitudinal and/or central axis of the perforating gun 200), for example by being disposed on a rotating shaped charge holder 206 (as shown in FIGS. 3-4 for example). In some embodiments, the perforating gun housing may include one or more banded scallop, which may be configured with respect to the shaped charges (although other embodiments may not include scallops at all). Disposing the shaped charges on a rotating holder 206 may enable automatic orientation of the shaped charges, for example via gravity. In other embodiments, the first shaped charge 12 and the second shaped charge 10 may be fixed relative to a housing 202 of the perforating gun 200, and in some embodiments, the perforating gun 200 may be configured for orientation. According to an aspect, the perforating gun 200 is connected to an alignment assembly that includes a tandem seal adapter (TSA) and one or more alignment subs to align and/or orient the perforating gun 200 with other adjacent wellbore tools while in a wellbore.

[0034] Specifically, FIG. 1 shows a cross-sectional front elevated view of an exemplary embodiment of a perforating gun 200, with position optimized shaped charges (e.g. first and second shaped charges 12, 10) in a well 38 (typically a horizontal well). The well 38 includes a wellbore casing 32, with a wellbore filling 34 (which typically includes a slurry or a fluid), and cement 36. The cement 36 bounds the wellbore casing 32 to the surrounding geological formation 30, while the wellbore filling 34 is disposed within the wellbore casing 32. The perforating gun 200 is decentralized in the wellbore casing 32, i.e., the perforating gun 200 is positioned on the bottom (defined by the direction of gravitational force (g)) of the casing 32 as a result of the gravitational force (g) acting on the perforating gun 200.

[0035] The perforating gun 200 includes a gun housing 202 with a hollow interior 204, a high clearance optimized shaped charge (e.g. the second shaped charge 10), and a low clearance optimized shaped charge (e.g. the first shaped charge 12). In the embodiment of FIG. 1, the shaped charges 10, 12 are positioned within the gun housing 202 relative to a rotational axis 14 of the perforating gun 200, so that the firing path of each shaped charge 10, 12 is directed radially away from the rotational axis 14 towards a wall of the gun housing 202 and in a direction transverse to a length of the gun housing wall. In an aspect, the rotational axis 14 of the perforating gun 200 is the central axis of the perforating gun 200 and is colinear with a rotational axis 14 of a shaped charge holder 206 (see FIG. 3 for example) provided in the perforating gun 200. [0036] According to an aspect, each of the shaped charges 10, 12 produces a perforating jet upon firing. The perforating jets are each configured to extend outward from the perforating gun 200 to the cased wellbore, in a direction that is substantially perpendicular to the housing 202. The high clearance optimized shaped charge (e.g. the second shaped charge 10) is configured to produce a high clearance perforating jet 16a. According to an aspect, the perforating jet 16a produced by the high clearance optimized shaped charge is initially wider (e.g. in comparison to perforating jet 16b) in proximity to the shaped charge 10. The low clearance optimized shaped charge (e.g. the first shaped charge 12) is configured to produce a low clearance perforating jet 16b. According to an aspect, the perforating jet 16b produced by the low clearance optimized shaped charge is initially narrower (e.g. in comparison to perforating jet 16a) in proximity to the shaped charge 12. The shaped charges and their corresponding perforating jets are configured to form entry holes dl, d2 of equal diameter in the wellbore casing 32 (e.g. despite the different clearance distances between the perforating gun 200 and the wellbore casing 32). For example, the perforating jets 16a, 16b may be configured to be approximately equal in width (e.g. diameter) once they penetrate the wellbore casing 32, and upon extending into the cement and the surrounding geological formation 30. As shown in FIG. 1, the perforating jets 16a, 16b may narrow as they extend from their respective shaped charge 10, 12. For example, each perforating jet 16a, 16b may be approximately conical in shape (e.g. as seen in the cross-section view of the perforating jets 16a, 16b shown, for example, in FIG. 1), with the wider base of the cone in proximity to the respective shaped charge 10, 12, and the cone narrowing as it extends out into the well 38. It is contemplated, however, that if the shaped charges 10, 12 are slotted shaped charges, the perforating jets may have a non-conical shape.

[0037] FIG. 2 illustrates an exemplary shaped charge 40 that may be configured for used with the perforating gun 200. Exemplary shaped charge embodiments include a shaped charge case 42 that forms a hollow cavity 44. While some embodiments of the shaped charge case 42 may have a generally conical shape, it is contemplated that the case 42 may be substantially rectangular (i.e., the shaped charge may be a slotted shaped charge) or have other shapes in some embodiments. The shaped charge 40 includes an explosive load 46 positioned in the cavity 44 of the shaped charge case 42. The explosive load 46 may include one or more explosive powders, including at least one of octahydro-1, 3,5, 7-tetranitro-l, 3,5,7- tetrazocine / cyclotetramethylene-tetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), pentaerythritol tetranitrate (PETN), hexanitrostibane (HNS), and 2,6- Bis(picrylamino)-3,5-dinitropyridine / picrylaminodinitropyridin (PYX). The explosive load 46 may include and triaminotrinitrobenzol (TATB). According to an aspect, the explosive load 46 includes at least one of HNS and diamino-3,5-dinitropyrazine-l-oxide (LLM-105). The explosive load 46 may include a mixture of PYX and TATB.

[0038] In some embodiments, a liner 48 is disposed adjacent to the explosive load 46.

The liner 48 may be configured to retain the explosive load 46 in the hollow cavity 44 of the shaped charge case 42, for example with the liner 48 disposed between the explosive load 46 and an opening of the shaped charge case 42 and/or the explosive load 46 disposed between the liner 48 and a closed end of the shaped charge case 42. The shaped charge case 42 may be formed from machinable steel, aluminum, stainless-steel, copper, zinc, and the like. The liner 48 may be formed from a variety of various powdered metallic and non-metallic materials and/or powdered metal alloys, and binders. Further details regarding shaped charges are described in US Patent No. 11,053,782, issued July 6, 2021, which is hereby incorporated by reference in its entirety to the extent that it is not inconsistent and/or incompatible with this disclosure. The exemplary shaped charge elements may be included in one or more of the shaped charges of the disclosed embodiments, such as the first shaped charge 12 and the second shaped charge 10.

[0039] Each of the shaped charges 10, 12 is oriented so that the perforating jets formed upon initiation of the shaped charges extend in a direction that is substantially perpendicular to the housing 202. In other words, each shaped charge 10, 12 is configured to expel its liner 48 outward from the perforating gun 200 (e.g. perpendicular to the housing 202). And in disclosed embodiments, each of the shaped charges 10, 12 is angularly spaced apart by the specified phasing (e.g. to be oriented at the specified wellbore phasing angle), as shown for example in FIGS. 5, 6, 7, and 11. In some embodiments, the plurality of shaped charges may be equally angularly spaced apart (e.g. equal phasing distribution). While the shaped charges 10, 12 are shown in FIGS. 3-4 as being radially aligned (e.g. disposed on a common radius of the perforating gun 200), in other embodiments, each shaped charge in the perforation gun 200 may be radially offset from each other (e.g. as they are disposed along the length of the perforating gun 200, similar to the configuration shown with respect to the tool string in FIG. 10). In an embodiment, each shaped charge 10, 12 may be arranged inline, such that they extend in a plane that is parallel to the rotational axis 14 of the perforating gun housing 202. For example, the first shaped charge may be positioned at a wellbore phasing angle of 180°, and the second shaped charge may be positioned at the wellbore phasing angle of 180° along the length of the perforating gun housing 202. [0040] The width of the perforating jet (e.g. at its base and/or in proximity to the corresponding shaped charge) for each shaped charge 10, 12 may be selected based on one or more shaped charge factors, such as the density or components of a liner for the shaped charge, an inner charge case geometry, a charge case material, a liner geometry, a liner blend/material, a liner weight, and the materials selected for the explosive load, and the weight of the explosive load. In some embodiments, at least one of the shaped charge factors of the first shaped charge 12 is different from the shaped charge factors of the second shaped charge 10.

[0041] In some embodiments, the first shaped charge 12 may comprise a first shaped charge liner having a first density, and the second shaped charge 10 may comprise a second shaped charge liner having a second density, with the first density being greater than the second density. For example, the first density may be greater than 10 g/cm³, and the second density may be about 5.8 g/cm³ to 9.2 g/cm³. In some embodiments, the second density may be less than 8 g/cm³. In some embodiments, the shaped charge factors of the first shaped charge 12 and second shaped charge 10, other than those affecting liner density, may be substantially the same. For example, the explosive load 46 and shaped charge case 42 may be substantially the same for the first shaped charge 12 and the second shaped charge 10. In some embodiments, the first shaped charge 12 and the second shaped charge 10 may be substantially identical, except for having liners of different density.

[0042] In some embodiments, the first shaped charge 12 may have a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9 (for example, about 1.8 to 2.9 in some embodiments), while the second shaped charge 10 may have a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45 (for example, about 0.5 to 1.3 in some embodiments). In some embodiments, shaped charge factors of the first shaped charge 12 and second shaped charge 10, other than those affecting liner to explosive mass ratio, may be substantially the same. In some embodiments, the outer shaped charge case geometry of the first shaped charge 12 may be substantially the same as an outer shaped charge case geometry of the second shaped charge 10.

[0043] With specific reference to FIG. 2, the shaped charge 40 for use in the perforating gun 200 may be optimized for different clearances by changing one or more parameters of at least one of the shaped charge liner 48, a, the shaped charge case 42, and the explosive load 46 used in the shaped charge. For example, adjustments to the parameters of the liner 48 may include any of the following: material or composition of the liner 48 (i.e., grain size and grain shape, quantities, alloys, and the like), and geometry of the liner 48 (i.e., shape, length, apex form, angles, and the like). According to an aspect, the liner 48 may include an apex form that is shaped as flat, sharp, or rounded. Adjustments to the parameters of the charge case 42 may include any of the following: material or composition of the charge case 42 (i.e., steel grade, other materials, e.g., zinc, production method, e.g., cold forged), and geometry of the case 42 (i.e., shape, inner and outer angles, inner and outer length, caliber, and wall thickness). Adjustments to the parameters of the explosive load 46 may include any of the following: amount or explosive mass, quality (i.e., grain size, pureness), and type/material (i.e., RDX, HMX, HNS, etc ).

[0044] According to an aspect, shaped charges with different internal or intrinsic qualities (e.g., inner charge case geometries and materials, liner geometries, materials and blends, mixtures, weights, explosives types and weights, and the like) may have an identical outer shaped charge case geometry. In combination with the perforating gun 200, a user can position a high clearance optimized shaped charge and a low clearance optimized shaped charge in the charge holder 206, add weights 214 to the charge holder 206 adjacent the low clearance optimized shaped charge to bias the orientation of the shaped charges, and position the shaped charge holder 206 in the perforating gun 200. With reference to FIG. 1 and the internally oriented embodiment shown in FIG. 3, when the gun is fired in the wellbore, the high clearance optimized shaped charge (e.g. second shaped charge 10) will fire at a 0-degree wellbore phasing angle and the low clearance optimized shaped charge (e.g. first shaped charge 12) will fire at a 180-degree wellbore phasing angle to produce equal diameter holes in the wellbore casing at 0-degrees and 180-degrees. According to an aspect, a first shaped charge 12 and a second shaped charge 10 may each have a different wellbore phasing angle or be oriented in different directions/phasing.

[0045] In an aspect, at least one of the liner material and blend of the shaped charge liner 48 may influence at least one of the hole size and hole consistency (relative to other shaped charges at different clearances) resulting from the shaped charge 10, 12. A liner mixture with a relative high density (for example, greater than 10 g/cm³) will typically produce a narrower jet compared to a liner mixture with a lower density (for example, less than 8 g/cm³). Therefore, assuming equal clearances, a relatively smaller entry hole diameter value will result from use of a higher density liner mixture, and a larger entry hole diameter value will result from use of a lower density liner mixture. In an aspect, the density range of liner design for shaped charge liners 48 which can produce a relatively large entrance hole diameter at significant perforating gun to casing pipe distances (e.g., up to approximately 40mm or 1.6 inches) is approximately 5.8 g/cm³ to 9.2 g/cm³.

[0046] In order to avoid uncontrolled or inconsistent shaped charge jet parti culati on, which will result in extremely inconsistent hole sizes in the casing 32, one may control the packing density of the particles in the shaped charge liner blend. A homogenously mixed liner blend (i.e., when different powder or varying densities, particle forms, and grain sizes are blended together) may also help to avoid uncontrolled or inconsistent shaped charge jet particulation. In an aspect, the metal powder grain may be round or spherical in shape, or alternatively, irregularly shaped or flaked. In an aspect, the grain size distribution may be adjusted for a specific liner 48 or shaped charge design. In an aspect, the range of metal grain sizes which result in the most effective packing density for different types of metal powders of different density may be between approximately 20 pm to 250 pm.

[0047] In an aspect, the ratio of liner weight of the shaped charge liner 48 to explosive weight of the explosive load 46 may influence the hole size and hole consistency resulting from the shaped charge 10, 12. In an aspect, a shaped charge liner 48 having a smaller weight or mass in comparison to the weight or mass of the explosive load 46 in the shaped charge liner 48 will produce a larger entry hole diameter than a shaped charge liner 48 having a larger weight or mass compared to the weight or mass of the explosive load 46 in the shaped charge 10, 12. In an aspect, the ratio range of liner weight to explosive weight in a shaped charge 40 that produces a relatively large entrance hole diameter may range from about 0.5 to 1.45 (for example, between about 0.5 and 1.3) in some embodiments. In an aspect, the ratio range of liner weight to explosive weight in a shaped charge 40 that produces a relatively small entrance hole diameter may range from about 1.5 to 2.9 (for example, between about 1.8 and 2.85 in some embodiments). In an aspect, the actual mass or weight of the shaped charge 40, the shaped charge liner 48, and the explosive load 46 may be adjusted depending on the needs of the application. However, if the mass or weight, or size, of the shaped charge liner 48 is too small, the shaped charge liner 48 may be mechanically weak and perform inconsistently. Additionally, if the liner mass or weight is not symmetrically distributed, then the shaped charge 40 may not produce a round or consistent hole size.

[0048] According to an aspect, generally, a shaped charge at a greater clearance (i.e., a high clearance shaped charge) from the gun outer surface to the wellbore casing 32 inner surface may include properties such as those discussed above for creating a larger entrance hole diameter, i.e., a wider perforating jet, because the perforating jet will typically narrow as it propagates further from the shaped charge, as the perforating jet “stretches” (e.g. as shown in FIG. 5). A shaped charge at a smaller clearance (i.e., a low clearance shaped charge) may include properties for creating a narrower perforating jet/ smaller entrance hole diameter. The entrance hole diameters of the high clearance shaped charge (e.g. second shaped charge 10) and the low clearance shaped charge (e.g. first shaped charge 12) may be substantially equal (e.g. when the perforating gun 200 is decentralized in the horizontal wellbore, as shown in FIG. 5 for example) because the perforating jet from the high clearance shaped charge will narrow along the greater clearance to the wellbore casing 32. Thus, each shaped charge in a perforating gun system may be designed/ selected to create substantially the same entrance hole diameter, based on the respective clearance of each shaped charge, by choosing particular corresponding properties such as, without limitation, liner density, physical properties including, e.g., packing density, homogeneity, parti cl e/grain size, geometry, and distribution, and liner/explosive weight ratio. As used herein, entrance hole diameters may be considered substantially equal if standard deviation is less than 10%, less than 5%, less than 3%, less than 1%, approximately 1%, or 1-3%, for example depending on specific embodiments. In some embodiments, high clearance distances may range from about 20-40 mm, while low clearance distances may range from about 0-18 mm, for example depending on casing grade and wall thickness.

[0049] According to an aspect, the shaped charges 10, 12 are rotatably mounted to a charge holder or a charge tube 206 (FIG. 3) and may be gravitationally oriented. According to an aspect, the high clearance optimized shaped charge (e.g. the second shaped charge 10) is oriented to a directly upward or 0-degree phasing position, and the low clearance optimized shaped charge (e.g. the first shaped charge 12) is oriented to a directly downward or 180- degree phasing position. While the shaped charges 10, 12 are shown in 0-degree and 180- degree wellbore phasing angle positions, other charge orientations are contemplated. For example, an orienting mechanism (e.g., a weight provided on the charge holder or charge tube) positioned between the shaped charges may orient the shaped charges to fire at 90- degree and 270-degree wellbore phasing angle, or the shaped charges may be angularly spaced apart by more or less than 180 degrees. It is contemplated that more than two shaped charges may be provided in the perforating gun 200.

[0050] FIG. 3 and FIG. 4 show an exemplary embodiment of a perforating gun 200 including the clearance optimized shaped charges 10, 12 positioned in the hollow interior 204 of the perforating gun 200. The shaped charges 10, 12 are mounted on a rotatable charge holder 206, which rotates around the rotation axis 14 via rotational bearings 212 that are non- rotatably coupled to an interior surface of the gun housing 202. The rotation towards the gravitation direction (g) may be done by applying one or more weights 214 on the determined downside of the charge holder 206 (e.g. the one or more weights 214 may be arranged to that they are eccentric in the charge holder 206, for example offset radially with respect to the rotational axis of the charge holder, and rotating the rotatable charge holder 206 based on gravity).

[0051] In FIGS. 3-4, the weights 214 are provided on the charge holder 206 in radial alignment (e.g. at the same phasing) with the low clearance optimized shaped charge (e.g. first shaped charge 12) and gravitationally oriented downward (e.g. at wellbore phasing angle of 180-degrees). In other embodiments, the eccentric weight(s) 214 may be positioned in different relationship to the shaped charges, based on the desired orientation of the shaped charges (for example, with the location/wellbore phasing angle of the weight 214 always being in the direction of gravity - e.g. 180-degree wellbore phasing angle - and the various shaped charges being angularly oriented accordingly based on their relationship to the weight 214). In the exemplary embodiment of FIG. 3, a detonator 210 (which may be positioned within a detonator holder 208 that is coupled to a rotational bearing 212) is configured to initiate the shaped charges 10, 12. The perforating gun 200 is sealed by a bulkhead 216 positioned at an end of the perforating gun 200 that is configured to connect to an adjacent perforating gun in the tool string. Additional details regarding a perforating gun configured for rotational positioning of shaped charges may be found in International Application Publication No. WO2020/249744, which is commonly owned by and assigned to DynaEnergetics Europe GmbH, and is hereby fully incorporated by reference herein to the extent that it is not inconsistent and/or incompatible with the present disclosure.

[0052] As a result of the weight distribution (e.g. of the weight 214 with respect to the shaped charges 10, 12 in the charge holder 206 of FIG. 3), the high clearance optimized shaped charge (e.g. second shape charge 10) may be oriented to a 0-degree phasing and the low clearance optimized shaped charge (e.g. first shaped charge 12) may be oriented to a 180- degree phasing. In an embodiment and with reference to FIG. 5, the second shaped charge 10 is oriented in a direction yi (which may be opposite the direction of gravity), and the first shaped charge 12 is oriented in a second direction yi (which may be the direction of gravity).

[0053] Some perforating gun 200 embodiments may have more than two shaped charges, for example depending on the needs of the application, and the direction and relative orientation of the shaped charges according to an embodiment may be adjusted or selected depending on the number of shaped charges used. For example, FIGS. 6-7 illustrate embodiments in which the perforating gun 200 includes three shaped charges oriented at different phasing. So, in addition to the first shaped charge 12 and the second shape charge 10, the perforating gun 200 may further include a third shaped charge (e.g. 12’ in FIG. 6 and 10’ in FIG. 7). In some embodiments, the first shaped charge 12 and the second shaped charge 10 are angularly spaced apart by about 120 degrees phasing, and the first shaped charge 12 and the third shaped charge are angularly spaced apart by about 120 degrees phasing (e.g. each of the three shaped charges 10, 12, and 10’ or 12’ may be spaced apart by 120 degrees from the adjacent shaped charges). In some embodiments, the first shaped charge 12, the second shaped charge 10, and the third shaped charge may be oriented at different wellbore phasing angles. In some embodiments, the third shaped charge (e.g. 12’ or 10’ respectively) may be configured to form a perforating jet similar to that formed by the first shaped charge 12 (as shown in FIG. 6 for example) or similar to that formed by the second shaped charge 10 (as shown in FIG. 7 for example).

[0054] For example, as shown in FIG. 6, the first shaped charge 12 may be oriented at approximately 120 degrees wellbore phasing angle, the second shaped charge 10 may be oriented at approximately zero degrees wellbore phasing angle, and the third shaped charge 12’ may be oriented at approximately 240 degrees wellbore phasing angle. The third shaped charge 12’ may be configured to form a perforating jet similar to that formed by the first shaped charge 12. For example, the third shaped charge 12’ and the first shaped charge 12 may be configured with narrower perforating jets than the second shaped charge 10. In some embodiments, the first shaped charge 12 and the third shaped charge 12’ may each have a shaped charge liner with a first density, the second shaped charge 10 may have a second shaped charge liner with a second density, and the first density may be greater than the second density. In some embodiments, the first shaped charge 12 and the third shaped charge 12’ may each have a shaped charge liner to explosive mass ratio which is greater than that of the second shaped charge 10, for example with the first shaped charge 12 and the third shaped charge 12’ having approximately the same liner to explosive mass ratio.

[0055] As shown in FIG. 7, in some embodiments, the first shaped charge 12 may be oriented at approximately 180 degrees wellbore phasing angle, the second shaped charge 10 may be oriented at approximately 60 degrees wellbore phasing angle, and the third shaped charge 10’ may be oriented at approximately 300 degrees wellbore phasing angle. According to an aspect, the third shaped charge 10’ may be configured to form a perforating jet similar to that formed by the second shaped charge 10. For example, the third shaped charge 10’ and the second shaped charge 10 may be configured to form a wider perforating jet than the first shaped charge 12. In some embodiments, the second shaped charge 10 and the third shaped charge 10’ may each have a shaped charge liner with a second density, the first shaped charge 12 may have a first shaped charge liner with a first density, and the first density may be greater than the second density. In some embodiments, the second shaped charge 10 and the third shaped charge 10’ may each have a shaped charge liner to explosive mass ratio which is less than that of the first shaped charge 12, for example with the second shaped charge 10 and the third shaped charge 10’ having approximately the same liner to explosive mass ratio. In some embodiments, otherwise (e.g. other than the liner density difference and/or explosive ratio difference) the first, second, and third shaped charges may be substantially the same. For example, the outer shaped charge case geometry of the first shaped charge 12, the second shaped charge 10, and the third shaped charge 10’ or 12’ may be substantially the same.

[0056] More specifically, as shown in FIGS. 6 and 7, three shaped charges are arranged around the rotation axis 14 and spaced apart by 120 degrees from one another (e.g. evenly angularly spaced). Depending on the needs of the application, in an embodiment with three shaped charges there may be two low clearance optimized shaped charges (e.g. first shaped charge 12 and third shaped charge 12’) positioned at an angle of 120 degrees and 240 degrees, respectively, with a single high clearance optimized shaped charge (e.g. second shaped charge 10) positioned at an angle of 0 degrees (see FIG. 6, for example). In a further embodiment, with three shaped charges there may be two high clearance optimized shaped charges (e.g. second shaped charge 10 and third shaped charge 10’) positioned at an angle of 60 degrees and 300 degrees, respectively, and a single low clearance optimized shaped charge (e.g. first shaped charge 12) positioned at an angle of 180 degrees (see FIG. 7, for example). While the exemplary embodiments of FIGS. 1-7 illustrate and are described with respect to the shaped charges mounted about a rotational axis 14 (e.g. mounted on a rotatable charge holder 206) for illustrative purposes, in other embodiments the shaped charges may be fixed with respect to the perforating gun housing 202. For example, orientation of the different shaped changes may be by external orientation of the entire perforating gun 200 and/or tool string.

[0057] FIGS. 8-9 illustrate embodiments in which the perforating gun 200 has four shaped charges oriented at different phasing. For example, in addition to the first shaped charge 12 and the second shaped charge 10, the perforating gun 200 may further include a third shaped charge 805 and a fourth shaped charge 810. The second shaped charge 10 illustrated in FIG. 8 may be configured to form a wider perforating jet than the first shaped charge 12. The third shaped charge 805 and the fourth shaped charge 810 are each configured to form a perforating jet that is wider than that formed by the first shaped charge 12, but not as wide as (e.g. narrower than) that formed by the second shaped charge 10. In some embodiments, the third shaped charge 805 and the fourth shaped charge 810 may be configured to form substantially identical perforating jets (e.g. perforating jets having substantially the same width in proximity to the corresponding shaped charge and/or at the point of penetration of the wellbore casing). In some embodiments, the first shaped charge 12 and the second shaped charge 10 may be angularly spaced apart by about 180 degrees phasing, the third shaped charge 805 and the fourth shaped charge 810 may be angularly spaced apart by about 180 degrees phasing, and the third shaped charge 805 and the fourth shaped charge 810 may each be angularly spaced apart from the first shaped charge 12 by about 90 degrees phasing. For example, the first shaped charge 12 may be oriented at approximately 180 degrees wellbore phasing angle, the second shaped charge 10 may be oriented at approximately zero degrees wellbore phasing angle, the third shaped charge 805 may be oriented at approximately 90 degrees wellbore phasing angle, and the fourth shaped charge 810 may be oriented at approximately 270 degrees wellbore phasing angle.

[0058] In some embodiments, the second shaped charge 10 may have a shaped charge liner with a second density, the first shaped charge 12 may have a first shaped charge liner with a first density, and the first density may be greater than the second density. Additionally, the third shaped charge 805 and the fourth shaped charge 810 may each have a liner with a third density, which may be less than the first density but greater than the second density. In some embodiments, the second shaped charge 10 may have a shaped charge liner to explosive mass ratio which is less than that of the first shaped charge 12, while the third shaped charge 805 and the fourth shaped charge 810 may each have a shaped charge liner to explosive mass ratio which is less than that of the first shaped charge 12 but more than that of the second shaped charge 10. For example, the third shaped charge 805 and the fourth shaped charge 810 may have approximately the same liner to explosive mass ratio. In some embodiments, otherwise (e.g. other than the liner density difference and/or explosive ratio difference) the first, second, third, and fourth shaped charges may be substantially the same. For example, the outer shaped charge case geometry of the first shaped charge 12, the second shaped charge 10, the third shaped charge 805, and the fourth shaped charge 810 may be substantially the same.

[0059] More specifically, in an embodiment and with reference to FIGS. 8 and 9, more than one shaped charge design or shaped charge liner design may be used in a single perforating gun 200 to minimize the entry hole diameter variations in a surrounding wellbore casing 32. In an aspect, four shaped charges may be arranged in a 90-degree phasing (e.g. angularly spaced apart by 90 degrees, for example evenly spaced) and configured to reduce entry hole diameter variations in the wellbore casing 32 (e.g. to produce equal entry holes). The shaped charges may be selected and/or configured based on the parameters described above. The second shaped charge 10 may be directed at a 0-degree orientation for a maximum clearance. The first shaped charge 12 may be directed at a 180-degree orientation for a minimum clearance. The third shaped charge 805 and fourth shaped charge 810 may be directed at a 90-degree and a 270-degree orientation, respectively, for medium clearance.

[0060] By way of example, shaped charges directed for medium clearance (e.g. third and fourth shaped charges 805, 810) may be configured to form a perforating jet having a width between that of shaped charges directed for minimum clearance (e.g. first shaped charge 12, which may be configured with a narrower perforating jet than the second shaped charge) and shaped charges directed for maximum clearance (e.g. second shaped charge 10, which may be configured with a wider perforating jet than the first shaped charge). For example, shaped charges directed for medium clearance (e.g. third and fourth shaped charges 805, 810) may each include a shaped charge liner having a density less than the density of the shaped charge directed for minimum clearance (e.g. first shaped charge 12), but more than the density of the shaped charge directed for maximum clearance (e.g. second shaped charge 10). In some embodiments, the shaped charges directed for medium clearance (e.g. third and fourth shaped charges 805, 810) may each have a ratio of liner weight to explosive weight of approximately 1.4 to 2.0 by mass. In some embodiments, the first shaped charge 12 and the second shaped charge 10 as shown in FIG. 9 may be similar to those described above with respect to FIGS. 1-5, and/or the third and fourth shaped charges 805, 810 may have a ratio of liner weight to explosive weight between those of the first shaped charge 12 and the second shaped charge 10. For example, the first shaped charge 12 may have a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9, while the second shaped charge 10 may have a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45. In some embodiments, the shaped charge directed for medium clearance (e.g. third and fourth shaped charges 805, 810) may each have liner density of approximately 9.2-10 g/cm³ or approximately 8-10 g/cm³. In some embodiments, the first shaped charge 12 and the second shaped charge 10 as shown in FIG. 9 may be similar to those described above with respect to FIGS. 1-5. For example, the first density of the liner of the first shaped charge 12 may be greater than 10 g/cm³, and the second density of the second shaped charge 10 may be about 5.8 g/cm³ to 9.2 g/cm³. FIG. 9 shows the exemplary arrangement of FIG. 8 employed in a wellbore with a large gun 200 to casing 32 clearance value. In some embodiments, as shown in FIGS. 8-9 for example, the two or more shaped charges may be fixed with respect to the housing 202 of the perforation gun. Typically, in such embodiments, the entire perforating gun may be oriented in order to orient the different shaped charges as desired. In other embodiments similar to FIGS. 8-9, the shaped charges may be mounted on a rotatable charge holder 206 similar to embodiments shown in FIGS. 1-7.

[0061] While the discussion above with respect to FIGS. 1 and 3-9 relates to a single perforating gun 200 having a plurality of different shaped charges (e.g. configured to produce different width perforating jets) at different wellbore phasing angles (and configured to produce equal entry hole diameters when the gun is decentralized in a horizontal wellbore), disclosed embodiments may similarly include a tool string having one or more perforating guns 200 for use in a horizontal wellbore casing 32. It should be understood that in some embodiments, one or more perforating guns 200 in the tool string may include a plurality of shaped charges. For example, any perforating gun 200 in the tool string may be similar to any of the disclosed perforating gun embodiments described herein (e.g. as shown in FIGS. 1, 3, 4, 5, 6, 7, 8, or 9). In some embodiments, each perforating gun 200 of the tool string may include one shaped charge or a plurality of shaped charges. In some embodiments, the tool string may include a single perforating gun 200, for example attached/linked to one or more other wellbore tools. In other embodiments, the tool string may comprise two or more perforating guns 200, which may be attached/linked together with one or more other wellbore tools in some embodiments.

[0062] For example, an exemplary tool string 1001 (see for example FIG. 10) may have one or more perforating guns 200 for use in a horizontal wellbore casing 32, and may include a first shaped charge 12 and a second shaped charge 10. Similar to the discussion above, the second shaped charge 10 may be configured to form a wider perforating jet than the first shaped charge 12, and the first shaped charge 12 and the second shaped charge 10 may be oriented at different phasing and/or wellbore phasing angles (e.g. with the specific shaped charges selected based on the clearance between each shaped charge and the wellbore, based on orientation/phasing). For example, the first shaped charge 12 may be configured for orientation across less clearance than the second shaped charge 10. The various permutations of the plurality of shaped charges discussed above with respect to a single perforating gun 200 (e.g. coordinating the wellbore phasing angle degree and perforating jet of each shaped charge in order to provide equal entry hole diameters despite different clearances) may also apply to a tool string 1001 having one or more perforating guns, and are included herein. [0063] In some embodiments, the first shaped charge 12 and the second shaped charge 10 may be disposed in a single perforating gun 200 of the tool string 1001. In other embodiments, the tool string 1001 may include a first perforating gun and a second perforating gun, with the first shaped charge 12 disposed in the first perforating gun and the second shaped charge 10 disposed in the second perforating gun. Similarly, other tool string 1001 embodiments may include three or four perforating guns, and each perforating gun 200 of the tool string 1001 may include at least one shaped charge. Such embodiments may employ a plurality of different shaped charges (e.g. configured to form different width perforating jets), which may each be oriented (e.g. using phasing) to produce equal entry holes despite different clearances. By way of example, FIG. 10 illustrates an exemplary tool string 1001 having a plurality of single shot perforating guns 200 (e.g. each perforating gun having only a single shaped charge), with each perforating gun 200 oriented to produce the desired wellbore phasing angle for the various shaped charges in the tool string 1001 and each of the shaped charges being selected (e.g. optimized) to produce a specific width of perforating jet (so that the tool string as a whole produces equal entry holes, despite different clearances for the various shaped charges in the tool string 1001 when the tool string 1001 is decentralized, as shown for example in FIG. 11).

[0064] More specifically, with reference now to FIG. 10 and FIG. 11, an exemplary embodiment of a string of single shot perforating guns 200 is shown with the single shaped charge (LI, L2, L2’) of each perforating gun 200 alternately oriented to shoot in different directions. In some embodiments, the perforating guns 200 of the tool string may be oriented in a repetitive pattern. As shown in FIG. 10, for example, alternating perforating guns 200 may respectively include a high clearance optimized shaped charge LI, which may be similar to the shaped charge shown at 0-degree wellbore phasing angle in FIG. 8 or FIG. 9 (as element 10), and a medium clearance optimized shaped charge L2, L2’ alternatingly oriented at 45-degree (for L2) and 45-degree (i.e., 315-degree) (for L2’) wellbore phasing angle. Accordingly, as shown in FIG. 11, looking from the front at a cross-section between the second perforating gun and the third perforating gun, the shaped charge L2’ of the 3 ^rd gun is oriented to fire at a -45-degree wellbore phasing angle from the shaped charge LI oriented at 0-degrees wellbore phasing angle in the fourth perforating gun, and the shaped charge L2 of the 5^th gun is oriented to fire at 45-degree wellbore phasing angle from the shaped charge LI oriented at 0-degrees, in the opposite direction from the shaped charge L2’ of the third perforating gun. The medium clearance optimized shaped charges L2, L2’ may be similar to those shown in FIGS. 8-9 (as elements 805 and 810). [0065] While specific shaped charges (e.g. configured to produce specific width perforating jets) and wellbore phasing angles are discussed with respect to FIGS. 10-11, other tool strings 1001 with different configurations (e.g. of wellbore phasing angles and/or shaped charge perforating jets) are contemplated. For example, any tool string 1001, having a plurality of shaped charges with different wellbore phasing angles which are selected to have corresponding perforating jets that result in equal entry hole diameters for a decentralized tool string 1001, are included in this disclosure. Accordingly, the exemplary embodiments discussed throughout this disclosure may provide equal entry hole diameters for shaped charges in a plurality of wellbore phasing angles (i.e., multi-phasing equal entry hole diameters) within a perforating gun system, housing, or tool string.

[0066] In an aspect, adjacent perforating guns 200 may be connected by male/female ends of the perforating gun housing 202 as shown in the exemplary embodiments of, e.g., FIG. 3 and FIG. 4. In other embodiments, the adjacent perforating guns 200 may be connected by tandem subs 1010 between the adjacent perforating guns 200, such as in the exemplary embodiment of FIG. 10. In some embodiments, the tandem sub 1010 may be or include a tandem seal adapter (TSA), which may be configured to couple to a first end of the perforating gun housing 202, for example via the internal threads. The TSA may be configured to allow for both physical and electrical coupling of two elements of a wellbore tool string 1001, for example, with the TSA therebetween. In FIG. 10, for example, the TSA (e.g. tandem sub 1010) may be coupled between two perforating guns 200, and may provide physical and electrical coupling therebetween. According to an aspect, the TSA may be part of an alignment assembly that includes one or more alignment subs to align and/or orient the perforating gun 200 with other adjacent wellbore tools while in a wellbore.

[0067] The TSA may include an electrical feedthrough assembly having a first electrical contact at one end and a second electrical contact on the opposite end. In some embodiments, the first electrical contact and the second electrical contact may both be disposed on a central axis of the TSA and/or may be configured to align with and/or contact the bulkhead 216 of an adjacent perforating gun 200 upon attachment to the perforating gun 200. The first electrical contact may be in electrical communication with the second electrical contact of the TSA, for example when the TSA is coupled between two elements of the tool string 1001, to allow electrical signals to pass through the TSA. The first electrical contact of the TSA may be in electrical contact with the bulkhead 216 of the perforating gun 200. In an exemplary embodiment, the electrical contact between the first electrical contact and the bulkhead 216 may be wireless or wire-free, i.e., the connection is made by direct physical contact between conductive elements (such as between the first electrical contact of the TSA and the bulkhead), without the use of wires. For purposes of this disclosure, “wireless electrical connection” means an electrical connection formed by physical contact between conductive components, without any wires electrically connecting the conductive components.

“Electrical contact” means either a conductive component for making a wireless electrical connection, or a state of physical, conductive contact between conductive components, as the context makes clear.

[0068] The first electrical contact and the second electrical contact of the TSA may be electrically coupled without wiring, for example by direct contact conduction, and may thereby provide for feedthrough of electrical signals through the TSA. Some embodiments of the TSA may further include one or more seals configured to seal adjacent elements of the tool string 1001 upon connection (e.g. to form a sealed connection therebetween). Further description of exemplary embodiments of the TSA and/or electrical feedthrough assembly may be found in U.S. Application Publication No. US 2020/217635, commonly-owned and assigned to DynaEnergetics Europe GmbH, which is hereby incorporated by reference in its entirety to the extent that it is not inconsistent and/or incompatible with this disclosure.

[0069] While FIG. 10 illustrates an exemplary tool string 1001 having a plurality of perforating guns, each with a single shaped charge, in other embodiments each perforating gun 200 of the tool string 1001 may have two or more shaped charges. In some embodiments, each perforating gun 200 of the tool string 100 may have one or more shaped charges. In some embodiments, each perforating gun 200 of the tool string 1001 may have the same number of shaped charges, but in other embodiments the number of shaped charges in each perforating gun 200 of the tool string 1001 may vary (for example, from 1 shaped charge to 4 shaped charges). Some embodiments of the tool string 1001 may have only a single perforating gun 200.

[0070] In addition to the one or more perforating gun 200, the tool string 1001 may comprise one or more additional wellbore tools. For example, the perforating gun housing 202 may also be connected at one or each end to a respective adjacent wellbore tool or other component of the tool string, such as a firing head, a weight bar or other weight module (such as disclosed in 17/363,876 filed June 30, 2021, commonly-owned and assigned to DynaEnergetics Europe GmbH, which is incorporated by reference in its entirety to the extent that it is not inconsistent and/or incompatible with the present disclosure), a plug, and/or a tandem seal adapter or other sub assembly. For example, the tool string may include a weight module. In some embodiments, the weight module may include a conductive body, extending in an axial direction, and an insulating cover covering an outer radial surface of the conductive body. In some embodiments, the conductive body may be configured to fit within a hollow interior of a weight module housing, and the insulating cover may be configured to electrically isolate the conductive body from the weight module housing. The conductive body may have a first contact portion provided at a first end of the conductive body and a second contact portion provided at a second end of the conductive body, opposite the first end in the axial direction. In some embodiments, the first contact portion may be in electrical communication with the second contact portion through the conductive body. In some embodiments, the conductive body may be eccentrically shaped (e.g. having its center of gravity offset from the center axis of the tool string) and/or configured to rotate or position the tool string via gravity.

[0071] Connecting the housing 202 to the adjacent component(s) typically includes screwing the perforating gun housing 202 and the adjacent component(s) together via complementary threaded portions of the housing 202 and the adjacent components and forming a connection and seal therebetween. In other embodiments, other types of connectors may be used to connect the perforating gun housing 202 to the adjacent component(s)/tool(s).

[0072] In some embodiments, the tool string 1001 may comprise more than one perforating gun 200. Once the perforating gun(s) 200 is properly positioned, a surface signal (e.g. an electrical signal) can actuate an ignition of a fuse or detonator 210, which in turn may initiate the detonating cord, which detonates the explosive shaped charges to penetrate/perforate the perforating gun housing 202 and wellbore casing 32, and/or the surrounding rock formation to allow formation fluids to flow through the perforations thus formed and into a production string.

[0073] The chart below provides an example of how varying shaped charge factors (such as liner density and/or liner weight to explosive weight ratio) can alter the size of entry holes when other factors are held constant (e.g. when the different shaped charges are fired across the same clearance distance). Typically, a loaded gun section would be placed inside a section of casing pipe. The loaded gun assembly would be laid horizontally inside a section of casing pipe, which is the exact same type and steel grade (e.g. Pl 10) as is used in real oil or gas wells. One side of the perforating gun assembly would lie on the lower side of the casing pipe. The entire gun and casing assembly would then be laid or hoisted inside a horizontal water ditch deep enough so that the casing is completely submerged under water. The perforating gun would then be initiated, and the corresponding hole sizes would be measured with calipers afterwards. In some embodiments, the gun may have a plurality of different shaped charges disposed along its length (e.g. spaced apart approximately one foot), with all of the shaped charges oriented the same direction (e.g. to have the same clearance). The following exemplary results may be illustrative:

In exemplary testing, the gun sizes typically tested may be 3 1/8” or 3.5” outer diameter, and the casing sizes and grades tested would typically be as follows:

4 y₂” Pl 10, 13.5 Ibs/ft - 15 Ibs/ft ( 3.92” - 3.826” ID) used with 3 1/8” gun carrier or smaller;

5” Pl 10, 20.3- 20.8 Ibs/ft (4.156” - 4.184” ID) used typically with 3 1/8” gun carriers;

5 y₂” Pl 10 17 Ibs/ft, 20 Ibs/ft, & 23 Ibs/ft (4.892”, 4.778“, 4.670“ ID’s accordingly), used with 3 1/8” or 3.5” carriers.

So by using different shaped charges (e.g. with different shaped charge factors) selected and oriented for specific clearance distances, equal entry holes may be formed (e.g. despite different clearance distances).

[0074] Aspects of this disclosure may include methods for producing multi-phasing equal entry hole diameters in a horizontal wellbore casing. An exemplary method may include the steps of: providing a perforating gun or a tool string with one or more perforating gun (which may have a first shaped charge, and a second shaped charge, which differ - e.g. being configured to form different width perforating jets); positioning the perforating gun or tool string in a radially decentralized position within the horizontal wellbore (e.g. at the bottom of the horizontal wellbore); detonating the first shaped charge and the second shaped charge; and forming a first entry hole from the detonation of the first shaped charge and forming a second entry hole from the detonation of the second shaped charge, wherein the first entry hole and the second entry hole have a substantially equal entry hole diameter.

[0075] In some embodiments, providing a perforating gun or tool string may include selecting the shaped charges based on wellbore phasing angle and/or expected clearance (e.g. selecting the first shaped charge to be configured for orientation across less clearance than the second shaped charge, while producing equal entry holes). For example, the second shaped charge may be configured to form a wider perforating jet than the first shaped charge, and the first shaped charge and the second shaped charge may be oriented at different phasing degrees (e.g. with the first shaped charge oriented across less clearance than the second shaped charge). In some embodiments, selecting the shape charges may include the steps of: selecting the first shaped charge with a first shaped charge liner having a first density, and selecting the second shaped charge with a second shaped charge liner having a second density, wherein the first density is greater than the second density. In some embodiments, selecting the shaped charges may include the steps of: selecting the first shaped charge to have a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9, and selecting the second shaped charge to have a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45.

[0076] Some embodiments may further include orienting the first shaped charge to be directed with less clearance (e.g. distance between the perforating gun and the wellbore casing) than the second shaped charge. For example, the method may comprise orienting the first shaped charge at 180-degree wellbore phasing angle and the second shaped charge at 0- degree wellbore phasing angle. In other embodiments, the method may include orienting the first and second shaped charges to an appropriate wellbore phasing angle (e.g. based on the specific shaped charges selected - such as the width of the perforating jet).

[0077] In some embodiments, the first shaped charge and the second shaped charge may be attached to (e.g. disposed within or provided on) a rotating shaped charge holder, and orienting the shaped charges may comprise rotating the shaped charge holder. In some embodiments, rotating the shaped charge holder may occur due to gravity. For example the method may further comprise providing an eccentric weight, configured to orient the first and second shaped charges (e.g. to rotate the rotatable shaped charge holder) to the appropriate wellbore phasing angle (e.g. based on the specific shaped charges selected). In some embodiments, the eccentric weight may be disposed in radial alignment with the first shaped charge. [0078] In some embodiments, the first and second shaped charges may be fixed with respect to the housing of the perforating gun. Some embodiments may further include using an orienting tandem sub to orient the first and second shaped charges (for example, by orienting the entire perforating gun or tool string). For example, the method may include attaching a tandem sun to the perforating gun. In some embodiments, external weight (e.g. external to the perforating gun) may be used to orient the perforating gun or tool string. For example, an external weight bar may be attached to the perforating gun and/or the tandem sub.

[0079] In some embodiments, the perforating gun or tool string may further include a third shaped charge configured to form a perforating jet similar to that formed by the first shaped charge or the second shaped charge, and the first shaped charge, the second shaped charge, and the third shaped charge may be oriented at different wellbore phasing angles. For example, the first shaped charge and the second shaped charge may be angularly spaced apart by about 120 degrees phasing, and the first shaped charge and the third shaped charge may be angularly spaced apart by about 120 degrees phasing. The method may further comprise detonating the third shaped charge, which forms a third entry hole substantially equal to the first and second entry holes.

[0080] In some embodiments, the perforating gun or tool string may further include a third and fourth shaped charge, with the third shaped charge and the fourth shaped charge each configured to form a perforating jet that is wider than that formed by the first shaped charge, but not as wide as that formed by the second shaped charge (e.g. the perforating jet of the third and fourth shaped charges may be substantially similar); the first shaped charge and the second shaped charge may be angularly spaced apart by about 180 degrees phasing; the third shaped charge and the fourth shaped charge may be angularly spaced apart by about 180 degrees phasing; and the third shaped charge and the fourth shaped charge may each be angularly spaced apart from the first shaped charge by about 90 degrees phasing. The method may further comprise detonating the third and fourth shaped charges, which forms a third entry hole and a fourth entry hole substantially equal to the first and second entry holes.

[0081] In some embodiments, the method may further comprise attaching a plurality of perforating guns together (e.g. to form a tool string). For example, each perforating gun may have a single shaped charge, and may be oriented for a specific wellbore phasing angle for its specific shaped charge. Each perforating gun may have a shaped charge selected based on the clearance when the perforating gun is oriented in the horizontal wellbore (e.g. to accomplish the phasing and produce equal entry holes). In other embodiments, one or more of the plurality of perforating guns attached to form the tool string may have two or more shaped charges, which may be configured with different wellbore phasing angles (as discussed above).

[0082] According to an aspect of the exemplary embodiments, orientation of the shaped charges to reduce entry hole diameter variations may be accomplished by externally orienting the perforating gun or tool string in which the shaped charges are positioned. For example, orientation of the shaped charges may be completed with the use of oriented tandem subs, external weight bars, or electrical-motor orientation devices, resulting in the rotation of the entire perforating gun containing the shaped charges relative to neighboring components on the tool string or rotation of the entire tool string.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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."

[0087] 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. This disclosure is presented for purposes of illustration and description. This disclosure is not limited to the form or forms disclosed herein. In the Detailed Description of this disclosure, for example, various features of some exemplary embodiments are grouped together to representatively describe those and other contemplated embodiments, configurations, and aspects, to the extent that including in this disclosure a description of every potential embodiment, variant, and combination of features is not feasible. Thus, the features of the disclosed embodiments, configurations, and aspects may be combined in alternate embodiments, configurations, and aspects not expressly discussed above. For example, the features recited in the following claims lie in less than all features of a single disclosed embodiment, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure. Advances in science and technology may provide variations that are not necessarily express in the terminology of this disclosure although the claims would not necessarily exclude these variations.

Claims

What Is Claimed Is:

1. A tool string having one or more perforating gun for use in a substantially horizontal wellbore casing, comprising: a first shaped charge; and a second shaped charge, wherein: the second shaped charge is configured to form a wider perforating jet than the first shaped charge; and the first shaped charge and the second shaped charge are configured to be oriented at different wellbore phasing angles.

2. The tool string of claim 1, wherein at least one of an inner charge case geometry, a charge case material, a liner geometry, a liner blend, a liner weight, an explosive type, and an explosive weight of the first shaped charge is different than at least one of an inner charge case geometry, a charge case material, a liner geometry, a liner blend, a liner weight, an explosive type, and an explosive weight of the second shaped charge.

3. The tool string of any of claims 1-2, wherein an outer shaped charge case geometry of the first shaped charge is the same as an outer shaped charge case geometry of the second shaped charge.

4. The tool string of any one of claims 1-3, wherein: the first shaped charge comprises a first shaped charge liner having a first density; the second shaped charge comprises a second shaped charge liner having a second density; and the first density is greater than the second density. The tool string of claim 4, wherein the first density is greater than 10 g/cm³; and the second density is about 5.8 g/cm³ to 9.2 g/cm³. The tool string of claim 5, wherein the second density is less than 8 g/cm³. The tool string of any one of claims 1-6, wherein the first shaped charge has a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9; and the second shaped charge has a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45. The tool string of any one of claims 1-7, wherein the first shaped charge has a 180- degree wellbore phasing angle; and the second shaped charge has a 0-degree wellbore phasing angle. The tool string of any one of claims 1-8, further comprising a third shaped charge; wherein: the third shaped charge is configured to form a perforating jet similar to that formed by the first shaped charge or the second shaped charge; the first shaped charge, the second shaped charge, and the third shaped charge are configured to be oriented at different wellbore phasing angles; and the first shaped charge and the second shaped charge are angularly spaced apart by about 120 degrees phasing, and the first shaped charge and the third shaped charge are angularly spaced apart by about 120 degrees phasing. The tool string of any one of claims 1-8, further comprising a third shaped charge and a fourth shaped charge; wherein: the third shaped charge and the fourth shaped charge are each configured to form a perforating jet that is wider than that formed by the first shaped charge, but not as wide as that formed by the second shaped charge; the first shaped charge and the second shaped charge are angularly spaced apart by about 180 degrees phasing; the third shaped charge and the fourth shaped charge are angularly spaced apart by about 180 degrees phasing; and the third shaped charge and the fourth shaped charge are each angularly spaced apart from the first shaped charge by about 90 degrees phasing.

11. The tool string of any one of claims 1-10, wherein the first shaped charge and the second shaped charge are disposed in a single perforating gun 200.

12. The tool string of any one of claims 1-10, wherein the one or more perforating gun comprises a first perforating gun and a second perforating gun, wherein: the first shaped charge is disposed in the first perforating gun; and the second shaped charge is disposed in the second perforating gun.

13. The tool string of any one of claims 1-12, wherein the first shaped charge and the second shaped charge are each provided on a rotating shaped charge holder 206.

14. The tool string of any one of claims 11-12, wherein the first shaped charge and the second shaped charge are fixed relative to a housing of the one or more perforating gun.

15. A perforating gun for use in a substantially horizontal wellbore casing, comprising: a first shaped charge; and a second shaped charge, wherein: the second shaped charge is configured to form a wider perforating jet than the first shaped charge; and the first shaped charge and the second shaped charge are oriented at different phasing.

16. The perforating gun of claim 15, wherein at least one of an inner charge case geometry, a charge case material, a liner geometry, a liner blend, a liner weight, an explosive type, and an explosive weight of the first shaped charge is different than at least one of an inner charge case geometry, a charge case material, a liner geometry, a liner blend, a liner weight, an explosive type, and an explosive weight of the second shaped charge. The perforating gun of claim 15, wherein: the first shaped charge comprises a first shaped charge liner having a first density; the second shaped charge comprises a second shaped charge liner having a second density; and the first density is greater than the second density. The perforating gun of claim 15 or claim 17, wherein the first shaped charge has a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9; and the second shaped charge has a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45. A method of producing multi -phasing equal entry hole diameters in a horizontal wellbore casing, comprising: providing a perforating gun having: a first shaped charge, and a second shaped charge 10, wherein the second shaped charge is configured to form a wider perforating jet than the first shaped charge, and the first shaped charge and the second shaped charge are configured to be oriented at different wellbore phasing angles; positioning the perforating gun in a radially decentralized position within the horizontal wellbore; detonating the first shaped charge and the second shaped charge; and forming a first entry hole from the detonation of the first shaped charge and forming a second entry hole from the detonation of the second shaped charge, wherein the first entry hole and the second entry hole have a substantially equal entry hole diameter. thod of claim 19, further comprising: selecting the first shaped charge with a first shaped charge liner having a first density, and selecting the second shaped charge with a second shaped charge liner having a second density, wherein the first density is greater than the second density; or selecting the first shaped charge to have a shaped charge liner to explosive mass ratio ranging from about 1.5 to 2.9, and selecting the second shaped charge to have a shaped charge liner to explosive mass ratio ranging from about 0.5 to 1.45.