Patent ID: 12221864

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to the drawings, where the purpose is to describe embodiments of this disclosure and not to limit the claims,FIGS.1-13Jshow a gun tube10.

Gun Tube

Gun tube10has a tube body12, a first end14with a first end fitting16, and a second end18with a second end fitting20. Gun tube10further includes a cavity114, charge openings116, charge clip openings117, and tabs130. Gun tube10is preferably cylindrical and formed of steel.

Charge openings116are configured to retain shape (or explosive) charges122, best seen inFIGS.1-8. Charge openings116can be of a suitable shape, size, and position to hold a specific type or size of shape charge122, and point the shape charge122outward in a specific direction. Charge clip openings117are configured so that clips132can be positioned on the outer wall of tube body12. Clips132are attached to wires that connect to the shape charges122in a manner known to those skilled in the art.

One or more weights124are positioned in cavity114. As shown, there are two weights124A,124B, although only one, or more than two, weights may be used. One or more weights124can be of any size, shape or weight suitable to move gun tube10so that the one or more weights124cause gun tube10to rotate relative to bearing assemblies26so the portion of gun tube10that retains one or more weights124is at the bottom of the wellbore (i.e., closest to the Earth's center) when gun tube10is positioned horizontally in a wellbore. Bearing assemblies26allow gun tube10to rotate around axis A in either direction relative the first end fitting16and the second end fitting20.

Weight124A as shown is semi-circular, comprised of steel, fills about half of the volume of cavity114, in which it is positioned, is juxtaposed first end14of gun tube10and extends about ⅓ of the length of gun tube10. Weight124A preferably weighs about 1¾ lbs. at sea level in this embodiment. Weight124B as shown is semi-circular, comprised of steel, fills about half the volume of cavity114, in which it is positioned, is juxtaposed second end18and extends about ⅕ of the length of gun tube10. Weight124B most preferably weighs about 0.8 lbs. at sea level in this embodiment. The size, weight, and configuration of one or more weights124can be varied to any suitable amount depending upon the application and diameter or length of gun tube10.

Gun tube10also includes tabs130that are used to retain the one or more weights124in cavity114. In the embodiment shown weight124A and weight124B are positioned in cavity114. Then tabs130are pressed down against the flat surface of weight124A to retain weight124in cavity114, and pressed down against the flat surface of weight124B to retain weight124B in cavity114. Thus, the tabs130in the Figures are shown in their pressed down position.

Alternatively, one or more weights124may be positioned differently relative to shape charges122in gun tube10than as shown. When positioned as shown, shape charges122will basically face straight upwards and straight downwards when gun tube10is positioned horizontally in a wellbore, because gravity pulls the one or more weights124to the bottom of the wellbore. If an operator instead wanted the shape charges122to be positioned and fired outward at an angle, such as 45°, 60°, or 90°, from straight up or straight down, the one or more weights124could be positioned differently in the cavity114. Then, when gravity pulls and orients the one or more weights124to the bottom of the horizontal wellbore, the shape charges122would be oriented to fire in the desired direction. So, gun tube10can have a plurality of tabs130sufficient to position the one or more weights124at multiple locations within cavity114. An operator can then select the desired location for the one or more weights within cavity114depending on the direction the operator would like shape charges122to fire.

End Fittings and End Contacts

First end fitting16includes an end contact22, an outer collar24, a bearing assembly26, and a support28. Second end fitting20has the same structure and components as first end fitting16. Second end fitting20includes an end contact22, an outer collar24, a bearing assembly26, and a support28. Because the respective components of each end fitting16and20have the same structure, only the components of first end fitting16will be described in detail. The same components or structures on second end fitting20are designated by the same reference numerals as those for first end fitting16.

End contact22has a body42with a first end44, second end46, and an annular center48. First end44has an electrical contact50. A stem52extends from second end46. Stem52has an opening55to which a wire can be connected. End contact22has an internal structure, known to those in the art, that enables electricity to be transmitted from electrical contact50to stem52, at which point electricity is transferred to one or more wires in electrical communication with stem52.

Body42is preferably comprised of an insulating material, such as plastic. One or more frangible elements, which are shown, are two tabs,54extend outward from second end46. As shown, the tabs are rounded and extend outward a maximum of about ⅛″ to 5/16″, or about ⅛″ to ¼″, or about ⅛″ to 3/16″, or about 3/16″ to ¼″ from body42. Another structure, such as a continuous or discontinuous annular ridge, or different shaped structures, could be used as the one or more frangible elements. The tabs are about 0.080″ to 0.150″, or about 0.10″ or about 0.110″, or about 0.120″ thick. Body42has a first annular portion48A, a second annular portion48B, and a central annular position48C. A spring56is positioned on first annular portion48A between central annular portion48C and tabs54.

The spring56used for each end contact22can be selected by an operator to be, for example, a high-tension spring, medium-tension spring, low-tension spring, or a spring of any suitable tension for the given application. The spring is selected in a manner known to those in the art, so that it ensures electrical connectivity to a device that electrical contact50touches in order to transmit electricity from the device to electrical contact50. In one embodiment, electrical contact50touches the stem of a plunger, which is described below. In another embodiment, the electrical contact50touches a mechanical switch (not shown), which is known to those skilled in the art. The spring pressure exerted by spring56must be firm enough to bias electrical contact50outward to ensure electrical conductivity, but not so firm that it could prematurely begin setting a mechanical switch due to wellbore vibrations or concussive blasts in adjacent guns.

For example, a spring could be selected to have a compression force of any suitable amount between about 2 lbs. and 10 lbs., or about 3 lbs. to 8 lbs., or about 4 lbs. to 7 lbs., or about 4 lbs. to 6 lbs., or about 5 lbs., or any amount from about 2 lbs. to about 15 lbs., or about 5 lbs. to about 15 lbs.

One or more frangible elements, which as shown are two tabs54are breakable (or frangible) from body42upon the application of an outward force along longitudinal axis A generated by an explosion of shape charges122. One or more frangible elements54could break, for example, upon the application of an explosive outward force of: about 30 lbs. or more, about 40 lbs. or more, about 50 lbs. or more, about 60 lbs. or more, about 70 lbs. or more, about 80 lbs. or more, about 90 lbs. or more, about 100 lbs. or more, or any explosive, outward force from about 30-200 lbs. or more, along axis A. The purpose of one or more frangible elements54breaking is so the electrical connection to gun tube10is broken when the shape charges122are exploded. Any suitable structure on end contact22could be used for this purpose.

Outer collar24is preferably comprised of metal, such as aluminum. Outer collar24has a first end58, a second end60having an opening61and an inner bearing surface63, an annular side wall62, an opening64in first end58, a cavity66, and one or more openings68in side wall62. Openings68are configured to receive grounding hardware items (such as ball plungers, or a spring and electrically conductive ball staked in place)70, or hardware, such as fastener103, attaching a ground wire101.

Bearing assembly26comprises a housing preferably circular in shape and has a first end72, a second end74, a body76with an outer wall78and an inner wall80, an opening82at first end72, and opening83at second end74, and a cavity84that retains ball bearings26A. Bearing assembly26could instead be what persons skilled in the art refer to as a thrust bearing. Any suitable structure to allow the rotation of tube body12around axis A may be utilized.

Support28is preferably comprised of metal, such as aluminum, and has a first end86, a second end88, a first body portion90that has a top surface92and an annular outer wall94, a second body portion96that has a top surface98, and an annular outer wall100, and an opening102therethrough. Opening102has two wing sections102A and102B sized and shaped so frangible elements (shown here as tabs)54of end contact22can pass therethrough. Top surface98has two wing recesses103A,103B that are positioned approximately 90° relative wing sections102A,102B, wherein the recesses103A,103B are configured to receive and retain one or more frangible elements54after they pass through wing sections102A,102B and end contact22is rotated, as described further below. A rib107is formed in opening102, preferably adjacent recesses103A,103B.

First end fitting16is assembled by placing spring56onto first annular portion48A of end contact22between one or more frangible elements54and central annular portion48C. Then end contact22is pressed through opening102of support28from second end88, as best seen inFIGS.13-13J. The one or more frangible elements54are aligned with and pushed through wing sections102A,102B and end contact22is then rotated (preferably about) 90° so the one or more frangible elements54align with wing recesses103A,103B. Pressure is released by the assembler and the one or more frangible elements54are then received and retained in wing recesses103A,103B, and end contact22is thus connected to support28without the use of tools or fasteners.

When tabs54are pressed through wing sections102A,102B, first end56A (adjacent one or more frangible elements54) of spring56presses against rib107inside opening102of support28. When the one or more frangible elements54are retained in wing recesses103A,103B, spring56is retained between rib107and central annular portion48C. Outward pressure (i.e., towards second end88and towards first end14of gun tube10) is applied by spring56to end contact22, which biases end contact22and electrical contact50to the first, extended position.

Bearing assembly26is positioned over second body portion96so that second end74and opening83are juxtaposed top surface92of first body portion90.

Outer collar24is positioned over end contact22, bearing assembly26and support28, so that electrical contact50extends through opening61of outer collar24, most preferably by any amount from about 1/16″ to about 5/16″. First end72and opening82of bearing assembly26are then juxtaposed inner bearing surface63of outer collar24.

One or more grounding hardware items70are positioned in one or more openings68and are preferably press fit into place and staked. The hardware items70are preferably either a ball plunger unit, or a combination of spring and electrically conductive ball bearing staked in place.

A ground wire101is connected to support28by a screw103being passed through lead101A and being threaded into opening29. An electrical lead105may then be positioned over stem52by pressing it on where it remains because of a pressure fit electrical lead105is preferably comprised of a flexible material such as elastomer. Electrical lead105is attached to one or more wires to receive electricity passing through end contact22. An advantage of electrical lead105, which is an insulative protective sheath with wires already attached, is case and speed of use, and creating a reliable connection. Presently, wires are placed by hand through opening55of stem52and then wrapped around stem52, and have a silicone tubing sleeve manually placed over the wire wrapping to provide electrical insulation and to keep stem52electrically isolated from the gun tube body12.

End contact22has a first position at which spring56biases it away from second end88of support28, and outward from first end fitting16, as shown, e.g., inFIGS.1-8. End contact22has a second, contracted position at which spring56is fully compressed. The distance between the first position and the second position is at least 0.150″, or at least ⅜″, or at least ½″, or at least ⅝″, or at least ¾″ or at least 1″, or any amount from 0.150″ to 1″, or from 150″ to 1.250″. Known end caps do not compress, or may compress only slightly (e.g., about ⅛″ or less). The advantage of the outward biasing and travel of the end contact22and electrical contact50is better reliability in maintaining an electrical connection. When a string of gun tubes10are placed in a wellbore as part of an assembly including sub-assemblies200(discussed below), stresses on the assembly can create gaps between gun tubes10and sub-assemblies200. Further, stresses, including downstream shape charges exploding, can cause upstream contacts to press against one another, which can lead to breakage and a gap where there is no electrical contact, or broken components that will no longer function. The outward bias and compressibility of the end contacts22help alleviate these problems.

Gun Tube With Indexing Weights

In an alternate embodiment shown inFIGS.28-35, a plate600or similar structure may be used to index one or more weights124′ to different positions in cavity114′ of gun tube10′. This allows an operator the flexibility to move one or more weights to a desired location, and when gravity acts upon the weights they are moved to be juxtaposed the bottom of the wellbore in which the gun tube10′ is positioned. The end fittings16′ and20′ in this embodiment again have a rotatable portion that enables the gun tube10′ to rotate around its longitudinal axis A′ so that shape charges122are oriented properly.

In this embodiment, gun tube10′ is in all respects the same as gun tube10except as described herein and as shown in the figures. Pins602and indexing apertures125,125A retain weights124A′,124B′ in position, as explained below. Gun tube10′ preferably does not include tabs, such as tabs130in gun tube10. Optionally, tabs130could be utilized to help retain weights124A′ and124B′ in position in the manner previously described.

As shown, each weight124A′ and124B′ in this embodiment have a semi-cylindrical, concave center portion1241′, although each may be of any suitable size, material, and configuration. Each weight124A ‘and124B’ has a first end126‘having a plurality of indexing apertures125A. Weight124A’ as shown has a semi-circular outer surface, is comprised of steel, fills about half of the volume of cavity114′, in which it is positioned, is juxtaposed first end14′ of gun tube10′ and extends about ⅓ of the length of gun tube10′. Weight124A′ preferably weighs about 1¾ lbs. at sea level in this embodiment. Weight124B′ as shown has a semi-circular outer surface, is comprised of steel, fills about half the volume of cavity114′, in which it is positioned, is juxtaposed second end18′ and extends about ⅕ of the length of gun tube10′. Weight124B′ most preferably weighs about 0.8 lbs. at sea level in this embodiment. The size, weight, and configuration of one or more weights124′ can be varied to any suitable amount depending upon the application and diameter or length of gun tube10′.

Each of one or more plates600is preferably comprised of steel about ¼″ to ½″ thick, preferably circular, and has a diameter slightly less than the inner diameter of tube body12′. Plate600is connected to the wall of cavity114(i.e., the inner wall of tube body12′) by any suitable means, such as soldering or mechanical fastening. If, for example, weights124A′,124B′ were utilized, one of the plates600would be juxtaposed weight124A at first end14′ of tube body12′ and another plate600would be juxtaposed weight124B at second end18′ of tube body12′. An operator could then rotate each of the weights124A′,124B′ to a desired location in cavity114depending on the direction the operator would like the shape charges122to fire, and retain the one or more weights124′ in the desired location using a pin602.

In this example, utilizing two weights, the weights124A′,124B′ would be moved by rotating each to the same relative position in cavity114′ and then using a pin602to fit through openings24P′ in each end fitting16′ and20′, through an indexing aperture125of each plate600, and into an aligned indexing aperture125A in weight124A′ and124B′. This retains each weight124A′,124B′ at the desired position in cavity114′ of gun tube10′.

If two plates are used, each plate600preferably has the same number of indexing apertures125at the same relative locations as the other plate600. The indexing apertures125preferably include indicia visible on the inner surface601(i.e., the surface facing away from an end14′ or18′ of gun tube10′ and towards its center) to identify each indexing aperture125, so the same indexed position for each plate600could be readily identified by an operator using the indicia. For example, each plate600may have eight indexing apertures125equally, radially spaced about all or part of the outer portion of the plate600(although a plate600may include any suitable number of apertures at any suitable locations). To make sure weights124A′,124B′ are the same relative positions in cavity114′, the respective apertures on each plate600would have the same indicia to designate indexing apertures125at the same relative position in cavity114′.

For example, if each plate600had eight apertures, the apertures could be designated by numerals 1-8. In this example, each weight124A′,124B′ would be at the same radial position in cavity114′ if a pin602was positioned in an indexing aperture125designated by the same indicia (such as numeral “4”) on each plate600. The indexing apertures125A in each weight124A′,124B′, could also include indicia. For example, if each weight124′ has eight indexing apertures125A, these apertures could also be designated by numerals 1-8. Using that example, an operator would know that weights124A′,124B′ would be the same relative position in cavity114′ if the indexing aperture125A designated by the same indicia (such as numeral “4”) for each weight124A′,124B′ was aligned with the indexing aperture125designated the same indicia (such as numeral “3”) in each plate600. A pin602would then be positioned through opening24P′ in each end fitting16′ and20′, through the indexing aperture125designated as “3” in each plate600, and into the indexing aperture125A designated as “4” in each weight124A′ and124B′.

First end fitting16′ is the same as first end fitting16except as described here and shown in the figures. Second end fitting20′ is the same as second end fitting20except as described here and shown in the drawings.

Bearing assembly26′ comprises a housing is preferably circular in shape and has a first end72′, a second end74′, a body76′ with an outer wall78′ and an inner wall80′, an opening82′ and a cavity84′ that retains ball bearings26A. Bearing assembly26′ could instead be what persons skilled in the art refer to as a thrust bearing. Any suitable structure to allow the rotation of tube body12around axis A′ may be utilized. Bearing assembly26′ has a smaller diameter than previously described bearing assembly26in order to provide space for pin602.

Support28′ is preferably comprised of metal, such as aluminum, and has a first end86′, a second end88′, a body portion90′ that has a front surface92′, an annular outer wall94′, and an opening102′ therethrough. Part of opening24P′ is formed through support28′ Opening102′ has two wing sections that are the same as previously described wing sections102A and102B. The wing sections are sized and shaped so frangible elements (shown here as tabs)54of end contact22can pass therethrough. Support28′ fits inside of bearing assembly26″ and rotates inside of outer collar24.

An opening24P′ is formed in the various components of end fitting16′ and/or20′ to permit insertion of a pin602through the end fitting16′ and/or20′, through an indexing aperture125in a plate600, and into an indexing aperture125A of a weight124′.

Sub-Assembly and Plunger

FIGS.16-18Eshow a sub-assembly200having a first end202with outer threads202A and opening202B, a second end204with outer threads204A and opening204B, a central portion206, and a central bore208with a first threaded end208A, and a second end208B. Central bore208extends through sub-assembly200from opening202B to opening204B.

The sub-assembly200is known in the art and is used to connect two gun tubes10, as generally shown inFIGS.23-26. Also known in the art is outer casing700, usually comprised of steel, that fits over each gun tube10. An outer casing protects gun tube10as it is moved into and through a wellbore. Each outer casing700has a first end702with internal threads702A, a second end704with internal threads704A, and a bore708extending therethrough. Each of the ends702,704threadingly connects to an outwardly-threaded end202or204of a respective sub-assembly200, as generally shown inFIGS.23-26. In this manner, a string of connected gun tubes10is produced.

Sub-assembly200requires a device to provide an electrical connection through it from one gun tube10to another gun tube10. One such a device is referred to herein as a plunger. InFIGS.14-14Ha plunger300is shown. In use, plunger300is received in central bore208of sub-assembly200as shown inFIGS.16-18E. Plunger300has an outer casing302preferably made of insulating material, the outer casing302having a first end301and a second end303, an electrically conductive core304with a first stop306and a second stop308, a first conductive stem structure310with a first stem310A and a first cylinder310B that has a diameter greater than the diameter of the first stem310A, a second conductive stem structure312with a second stem312A and a second cylinder312B that has a diameter greater than the diameter of the second stem312A, preferably a first spring or other biasing structure314between first conductive stem structure310and first stop306, and a second spring or other biasing structure316between second conductive stem structure312and second stop308. First stem310A has a first distal tip311and second stem312A has a second distal tip313. Electrically-conductive core304has a first cavity309in which spring314is positioned and a second cavity309A in which spring316is positioned.

Outer casing302as shown has an annular outer surface with one or more (and as shown, two) annular grooves315juxtaposed first end301. Each groove315includes an O-ring318. O-rings318can be selected of varying durometers or materials for the environment in which they are used. O-rings318create an interference fit in central bore208to prevent wellbore liquid from entering central bore208. Outer casing302at first end301has a greater diameter than the rest of outer casing302. The increased diameter is any amount from about 0.100″ to 0.300″, and the purpose is to create a snug fit in central bore208.

As shown, plunger300has two stem structures310,312that are moveable between a first, extended, position and a second, contracted position, but plunger300(or plunger300″) could have only one such structure and the other could stem structure could have just one position.

Springs314,316each permit from about 0.150″ to about 1.250″ of travel along longitudinal axis B, of respectively, first conductive stem structure310and second conductive stem structure312. As shown, each stem structure310,312has a first, extended position (shown in the figures), and a second, compressed position in which respective springs314,316are compressed. Each stem structure310,312can move independently of the other. Springs314,316can be selected by an operator to have a compressive force suitable for the particular condition to which plunger300will be subjected. For example, a spring314,316may have any compressive force or spring rate between about 2 lbs. and about 40 lbs., such as about 2 lbs. to about 40 lbs., about 2 lbs. to about 15 lbs., about 2 lbs. to about 10 lbs., about 4 lbs. to about 15 lbs., or about 4 lbs. to about 10 lbs., or any force from about 10 lbs. to about 50 lbs., such as about 15 lbs., about 20 lbs., about 25 lbs., about 30 lbs., about 35 lbs., about 40 lbs., about 45 lbs., or about 50 lbs.

The purpose of biasing, moveable stem structures310,312outward, and to permit their travel along axis B between a first, extended position and a second, compressed position, is to help ensure that an electrical connection is maintained when a string of gun assemblies10and sub-assemblies200are positioned in a wellbore. The string can be subject to stresses that push the respective components together, which can damage electrical connections if they cannot compress, and thus can move the respective electrical connections apart. The biasing of the stems outward to an extended position, and the ability of the stems to compress without breaking, helps to alleviate this problem. This structure permits play between the electrical connections, as opposed to a rigid connection that can more easily be damaged.

Plunger300could also include exterior grounding arms having the same configuration as exterior grounding arms414for DWG400, which are shown in the Figures and described below.

Alternately, a plunger300′, as shown inFIGS.15-15Amay be utilized. Plunger300′ is in all respects the same as plunger300except that outer casing302′ has a uniform outer diameter, so the portion of outer casing302′ juxtaposed first end301′ would have the same diameter as the portion juxtaposed second end303′.

A metal retainer nut220may be screwed into central bore208to retain plunger300or300′, as shown inFIGS.16,16A, which helps retain plunger300in central bore208. Retainer nut220has a central opening222in which first stem310A is positioned.

Dart Retainer

Each end202,204, or only one end202or204, of a sub-assembly200may include a dart retainer250or380. Further, a dart retainer250or380may be used with a double wire through with ground, which is described below. If a dart retainer is used, it would be in place of a metal retainer nut220.

As shown inFIGS.17-17E, a small dart retainer250is an insulating sheath that is preferably comprised of rubber or elastomer, such as silicone rubber. It helps prevent short circuits by a loose wire touching sub-assembly200. Only one dart retainer250shall be described because if a sub-assembly200utilizes two, the second dart retainer250would be utilized in the same manner, but would be at second end208B of sub-assembly200with second stem312A.

Dart retainer250has a first portion250B with a first diameter, a second portion250A with a second diameter, and an opening252therethrough. Dart retainer250is preferably configured so first portion250B fits in first threaded end208A of central bore208and opening252at least partially surrounds first stem310A of plunger300.

Alternatively, as shown inFIGS.18-18E, a large dart retainer380is an insulating sheath that is preferably comprised of rubber or elastomer, such as silicone rubber. It helps prevent short circuits by a loose wire touching sub-assembly200, and also helps prevent shrapnel from damaging the surface of central bore208. Only one dart retainer380shall be described because if a sub-assembly200utilizes two, the second dart retainer380would be utilized in the same manner, but would be at second end208B of sub-assembly200with second stem312A.

Dart retainer380has a first portion380B with the same first diameter as first portion250B, a larger second portion380A with a diameter greater than that of second portion250A, and an opening382. First portion380B is configured to be positioned in first threaded end208A of central bore208and opening382at least partially surrounds first stem310A of plunger300. Second portion380A is sized to fit against the wall of opening202B in order to provide protection and help prevent shorts.

Double Wire Feed Through with Ground

FIGS.19-22Gshow a double wire with ground (“DWG”)400and500. The DWG400could be used instead of a dual plunger in a sub-assembly200to transmit electricity to a gun tube10.

If a DWG is used, end contacts22are not required in the end fittings16,20of gun tube10because electricity is conducted through wires that are in contact with second conductive stem412and with the shape charges122. Alternatively, a DWG could be used with an end contact22.

DWG400is configured to be received in central bore208of sub-assembly200. DWG400has an outer housing402preferably made of insulating material, an electrically conductive core404, a first end406, a second end408, a first conductive stem410, a second conductive stem412, and optionally a spring or other biasing structure between first conductive stem410and electrically conductive core404.

DWG400also preferably has one or more exterior grounding arms414to securely ground to the central bore208of the sub-assembly200. An insulative protective sheath, which may be heat shrink tubing450, can be manually placed or affixed over second conductive stem412of the DWG400for secure attachment of wires452, instead of having to connect wires to second conductive stem412.

One or more annular groves416are preferably formed on the outer surface of outer housing402. Each groove preferably receives an O-ring (or gasket) of varying durometer418that pressure fits into central bore208of sub-assembly200.

One or more exterior grounding arms414are positioned adjacent grooves414A on outer housing402. When DWG400is pressed into central bore208of sub-assembly200, one or more exterior grounding arms414press against the annular wall of central bore208to help ensure the grounding of DWG400.

Intelligent Gun Tube

As shown inFIG.27, gun tube10′ is a smart assembly that is the same in all respects as gun tube10except it does not require one or more weights124(although it may still include them), and it includes a motor M on first end14and/or on second end18. A motor M may be attached to end fitting16and/or20. An accelerometer or other sensor (e.g., 3-axis (magnetometer), 6 axis (magnetometer plus accelerometer) or 9 (magnetometer plus accelerometer plus gyroscope), degree of freedom (“DOF”) device may be used to detect the relative rotational position of gun tube10′ in a wellbore. The sensor can thus assist an operator in determining the position of the shape charges122in the wellbore. The operator can then control the one or more motors to rotate gun tube10′ and position the shape charges122where the operator wants them before firing them. A signal could be sent wirelessly, or by a wired connection, from the sensor to the operator who can use a controller (such as a computer or cell phone) to directly or indirectly operate the one or more motors to orient the gun tube10′.

Perforating Gun Assembly

FIGS.23-26show a perforating gun assembly1000. Gun assembly1000includes previously-described gun tube10, a previously-described sub-assembly200, each of which include a plunger300. Alternatively, one or both sub-assemblies could include a previously-described DWG400at respective ends204of each sub-assembly200. In that case, end contacts22need not be used. Wires could extend from first conductive stem410through cavity114of tube body12and be connected to wires452at second conductive stem412of DWG400in the downstream sub-assembly200.

In this embodiment, gun tube10is pressed into outer casing700. Outer casing700has a first end702with internal threads702A, a second end704with internal threads704A, an outer surface706and an internal cavity708B with an inner surface708A. When gun tube10is pressed into internal cavity708B, grounding hardware items70, which may be ball plungers, are compressed to their second compressed position, and they bias back to the first, extended position when they align with grooves (not shown) on inner surface708A that have a slightly larger diameter than the rest of internal cavity708B. In that manner, gun tube10is affixed in position in outer casing700.

After gun tube10is positioned, sub-assemblies200are screwed onto each end702,704of outer casing700. As best seen inFIG.26, when assembled, second conductive stem structure312of plunger300in forward sub-assembly200is in contact with electrical contact50of first end fitting16. First conductive stem structure310of plunger300in rear sub-assembly200contacts electrical contact50of second end fitting20.

Some non-limiting examples of embodiments of this disclosure follow:

Example Set 1

Example 1: A plunger configured to fit in a central bore of a sub-assembly for a wellbore perforating gun assembly, the plunger comprising: an outer casing comprised of insulating material and having a first end; a first end portion comprised of electrically conductive material and including a first conductive stem, the first conductive stem having a first, extended position, and a second, contracted position.

Example 2: The plunger of example 1, wherein the outer casing further comprises a second end; and the plunger further comprises a second end portion comprised of electrically conductive material and including a second conductive stem, the second conductive stem having a first, extended position and a second, contracted position.

Example 3: The plunger of example 1 or 2, wherein the distance between the first, extended position of the first conductive stem and the second, contracted position of the first conductive stem is from 0.150″ to 1.250″.

Example 4: The plunger of example 2, wherein the difference between the first, extended position of the second conductive stem and the second, contracted position of the second conductive stem is from 0.150″ to 1.250″.

Example 5: The plunger of example 1 or 4, wherein the distance between the first, extended position of the first conductive stem and the second, contracted position of the first conductive stem is from 0.150″ to 1.250″.

Example 6: The plunger of any of examples 1-5, wherein the first end portion further includes a first cylinder connected to the first conductive stem and positioned inside of the outer housing, wherein the first cylinder has a diameter that is greater than a diameter of the first conductive stem.

Example 7: The plunger of any of examples 2 or 4-6, wherein the second end portion further includes a second cylinder connected to the second conductive stem and positioned inside of the outer housing, wherein the second cylinder has a diameter that is greater than a diameter of the second conductive stem.

Example 8: The plunger of any of examples 1-7, wherein the first conductive stem has a first distal tip that is positioned past the first end of the outer casing when the first conducive stem is in its first, extended position.

Example 9: The plunger of any of examples 2 or 4-6, wherein the second conductive stem has a second distal tip that is positioned past the second end of the outer casing when the second conductive stem is in its first, extended position.

Example 10: The plunger of any of examples 1-9 that further comprises a first spring that biases the first conductive stem to its first, extended position, wherein the spring is compressed when the first conductive stem is in its second, contracted position.

Example 11: The plunger of any of examples 2, 4-6, or 9 that further comprises a second spring that biases the second conductive stem to its second, extended position, wherein the spring is compressed when the second conductive stem is in its second, contracted position.

Example 12: The plunger of example 11 that further comprises a first spring that biases the first conductive stem to its first, extended position, wherein the spring is compressed when the first conductive stem is in its second, contracted position.

Example 13: The plunger of example 12, wherein the first spring and the second spring each has a compressive force from 5 lbs. to 15 lbs.

Example 14: The plunger of example 12, wherein the first spring and the second spring each has a compressive force from 2 lbs. to 20 lbs.

Example 15: The plunger of example 12, wherein the first spring and the second spring each has a compressive force from 5 lbs. to 30 lbs.

Example 16: The plunger of any of examples 1-15 that has an outer casing length of between 2″ and 12″.

Example 17: The plunger of any of examples 1-16 that has an outer casing length of between 2″ and 5″.

Example 18: The plunger of any of examples 1-17, wherein the insulating material is plastic.

Example 19: The plunger of any of examples 1-18, wherein the outer casing has an outer surface and at least one annular groove on the outer surface, and an O-ring in the at least one annular groove.

Example 20: The plunger of any of examples 1-19 that has two annular grooves on the outer surface, and an O-ring in each of the two annular grooves.

Example 21: The plunger of example 6, wherein the first cylinder is integrally formed with the first conductive stem.

Example 22: The plunger of example 10 that further comprises a conductive inner core and the first end portion further includes a first cylinder, the first cylinder being positioned inside of the outer housing, and the first spring being positioned between the conductive inner core and the first cylinder.

Example 23: The plunger of example 11 that further comprises a conductive inner core, and the second end portion further includes a second cylinder, the second cylinder being positioned inside of the outer housing, and the second spring being between the conductive inner core and the second cylinder.

Example 24: The plunger of example 7, wherein the second cylinder is integrally formed with the second conductive stem.

Example 25: The plunger of any of examples 1-24, wherein the first end is configured to be rotated by a tool.

Example 26: The plunger of example 25, wherein the first end has a shape selected from the group consisting of one of the following: hexagonal, Torx, quadrangle, Allen head, Star drive, and other driving configuration.

Example 27: A sub-assembly having a first end with a first opening, a second end with a second opening, and a central bore between the first opening and the second opening, and the plunger of example 2 positioned in the central bore and configured so the first, conductive stem is positioned at least partially in the first opening.

Example 28: The sub-assembly of example 27, wherein the first opening has a surface, and the central bore has a surface, and that further includes a dart retainer that surrounds at least part of the first conductive stem and contacts the surface of the central bore.

Example 29: The sub-assembly of example 28, wherein the dart retainer has a first section with a first diameter, a second section with a second diameter, and an opening therethrough, and the first conductive stem is positioned in the opening, and the first section contacts the surface of the central bore, and the second section contacts the surface of the first opening.

Example 30: The sub-assembly of example 29, wherein the dart retainer is comprised of silicone rubber.

Example 31: The sub-assembly of any of examples 27-30 that further comprises a second conductive stem having a second distal tip that is positioned outside of the central bore and positioned in the second opening.

Example 32: The sub-assembly of any of examples 27-31, wherein the first conductive stem has a first distal tip that is positioned outside of the central bore and positioned outside of the first opening.

Example 33: The sub-assembly of any of examples 27-32 that further comprises a second conductive stem having a distal tip that is positioned outside of the central bore and positioned outside of the second opening.

Example 34: The sub-assembly of example 28, wherein the second conductive stem is positioned at least partially in the second opening, and that further includes a dart retainer that surrounds at least part of the first second conductive steam and contacts the surface of the central bore.

Example 35: The sub-assembly of example 34, wherein the dart retainer has a first section with a first diameter, a second section with a second diameter, and an opening therethrough, and the second conductive stem is positioned in the opening, and the first section contacts the surface of the central bore, and the second section contacts the surface of the second opening.

Example Set 2

Example 1: A gun tube comprising:a body having a first end, a second end, a cavity, and a longitudinal axis;one or more weights in the cavity, the one or more weights configured to rotatethe body around the longitudinal axis based on gravity acting on the one or more weights; anda first end fitting attached to the first end of the body, the first end fitting rotationally connected to the body.

Example 2: The gun tube of example 1, wherein the first end fitting includes a first bearing housing.

Example 3: The gun tube of example 1 or 2 that further includes a second end fitting attached to the second end of the body, the second end fitting rotationally connected to the body.

Example 4: The gun tube of example 3, wherein the second end fitting includes a second bearing housing.

Example 5: The gun tube of any of examples 1-4, wherein the first end fitting further comprises a first end contact having a first, extended position and a second, contracted position.

Example 6: The gun tube of any of examples 3-4, wherein the second end fitting comprises a second end contact having a first, extended position and a second, contracted position.

Example 7: The gun tube of any of examples 1-6, wherein the one or more weights comprises two separate weights, a first weight and a second weight.

Example 8: The gun tube of example 7, wherein the first weight is juxtaposed the first end of the tube body, and the second weight is juxtaposed the second end of the tube body.

Example 9: The gun tube of any of examples 1-8, wherein each of the one or more weights has a semi-cylindrical shape.

Example 10: The gun tube of example 7, wherein the first weight weighs ⅞ lbs. at sea level and the second weight weighs 1¾ lbs. at sea level.

Example 11: The gun tube of example 7, wherein the second weight is at least twice as heavy as the first weight.

Example 12: The gun tube of any of examples 1-11, wherein the one or more weights collectively weigh from 2 lbs. to 8 lbs. at sea level.

Example 13: The gun tube of any of examples 1-12, wherein the one or more weights are comprised of steel.

Example 14: The gun tube of any of examples 1-13, wherein the one or more weights is collectively one of the following percentages of the weight of the gun tube without the weight: at least 15%, at least 20%, at least 30%, at least 40%, and at least 50%.

Example 15: The gun tube of example 7, wherein the first weight is 2″-3″ in length and the second weight is 3″-8″ in length.

Example 16: The gun tube of any of examples 1-15, wherein the at least first end fitting comprises:an outer collar;a bearing housing that includes ball bearings and a central opening; anda support having a first portion with a first diameter and a second portion with a second diameter that is greater than the first diameter, wherein the bearing housing is positioned on the first portion and the central opening surrounds at least part of the first portion, and the outer collar is fastened to the support.

Example 17: The gun tube of any of examples 1-16 that further comprises one or more charge openings configured to receive an explosive charge.

Example 18: The gun tube of example 17 that further comprises one or more explosive charges in the one or more charge openings.

Example 19: The gun tube of example 17 that further comprises one or more clip openings configured to receive charge clips.

Example 20: The gun tube of example 19 that comprises one or more clips in the one or more clip openings.

Example 21: The gun tube of example 16, wherein the first end fitting further includes a first end contact having a first, extended position and a second, contracted position, and that also comprises a second end fitting having a second end contact including a first, extended position and a second, extended position.

Example 22: The gun tube of example 16, wherein the outer collar has one or more openings, wherein at least one of the one or more openings contains grounding hardware biased to a first, extended position, and that also has a second, contracted position.

Example 23: The gun tube of any of examples 1-22, wherein the first end fitting comprises an end contact having a first end that comprises a stem, the stem being positioned inside of the cavity, and the end contact having a second end, the second end comprising an electrical contact that is positioned outside of the body.

Example 24: The gun tube of example 23, wherein the end contact is configured to transmit electricity therethrough.

Example 25: The gun tube of any of examples 1-24, wherein the first end fitting comprises a first end contact that includes a housing and one or more frangible elements extending outwardly from the housing.

Example 26: The gun tube of example 25 that further comprises a second end fitting that includes a second end contact having a housing and one or more frangible elements extending outwardly from the housing.

Example 27: The gun tube of example 25 or 26, wherein the housing and frangible elements are comprised of plastic and the frangible elements are configured to break away from the housing upon the application of explosive, outward axial force caused by explosion of one or more explosive charges in the gun tube.

Example 28: The gun tube of example 5, wherein the first end contact is biased towards the first, extended position.

Example 29: The gun tube of example 6, wherein the second end contact is biased towards the first, extended position.

Example 30: The gun tube of example 28 that further includes a spring on a housing of the first end contact, the spring configured to bias the first end contact to the first, extended position, and the spring configured to compress when the first end contact moves to its second, contracted position.

Example 31: The gun tube of example 29 that further includes a spring on a housing of the second end contact, the spring configured to bias the first end contact to the first, extended position, and the spring configured to compress when the first end contact moves to its second, contracted position.

Example 32: The gun tube of example 5, wherein the end fitting includes an opening in which the first end contact is positioned.

Example 33: The gun tube of any of examples 25-27, wherein the first end fitting further includes a support that has an opening configured to receive the one or more frangible elements, and wherein the first end contact has a first rotated position in which the one or more frangible elements fit through the opening and a second rotated position in which the one or more frangible elements do not fit through the opening.

Example 34: The gun tube of example 27, wherein the one or more frangible elements are configured to break away from the housing when about 30 lbs. or more of explosive, outward longitudinal axial force is applied to them.

Example 35: The gun tube of example 5, wherein the first end contact comprises a stem that includes a through hole, the through hole configured to receive one or more wires.

Example 36: The gun tube of example 6, wherein the second end contact comprises a stem that includes a through hole, the through hole configured to receive one or more wires.

Example 37: The gun tube of any of examples 1-36, wherein the body further comprises a plurality of tabs for retaining the one or more weights.

Example 38: The gun tube of any of examples 1-37 that further includes tabs at different positions on the body to maintain the one or more weights at different, respective positions within the cavity.

Example 39: The gun tube of any of examples 1-38, wherein the body further comprises tabs that have a first, open position, and a second, closed position in which the tabs retain the one or more weights in the cavity.

Example 40: The gun tube of any of examples 1-39 that further includes an outer casing positioned over and around the body, the outer casing having a first end and a second end.

Example 41: The gun tube of example 39 that further comprises a sub-assembly connected to one end of the outer casing.

Example 42: The gun tube of example 39 that further comprises a first sub-assembly connected to the first end of the outer casing and a second sub-assembly connected to the second end of the outer casing.

Example 43: The gun tube of example 41, wherein the sub-assembly is threadingly connected to the outer casing.

Example 44: The gun tube of example 42, wherein the first sub-assembly is threadingly connected to the first end of the outer casing and the second sub-assembly is threadingly connected to the second end of the outer casing.

Example 45: The gun tube of example 41 that further comprises a plunger in the sub-assembly.

Example 46: The gun tube of example 45, wherein the plunger has a longitudinal axis and an electrical connection running through it.

Example 47: The gun tube of example 45 that further includes an electrically insulating outer casing around at least part of the plunger and the outer casing has a first end and a second end.

Example 48: The gun tube of example 47, wherein the electrically insulating casing is comprised of plastic.

Example 49: The gun tube of example 43, wherein the plunger has a body, a cavity, a first end, and a second end, a first conductive stem, and a second conductive stem, wherein the first contact stem extends past the first end of the outer casing, and the second contact stem extends past the second end of the outer casing.

Example 50: The gun tube of example 49, wherein the first conductive stem has a first, extended position and a second, contracted position.

Example 51: The gun tube of example 50, wherein the second conductive stem has a first, extended position and a second, contracted position.

Example 52: The gun tube of example 50, wherein the distance between the first, extended position and the second, contracted position of the first conductive stem is between 0.150″ and 1.250″.

Example 53: The gun tube of example 51, wherein the distance between the first, extended position and the second, contracted position of the second conductive stem is between 0.150″ and 1.250″.

Example 54: The gun tube of example 50, wherein the first conductive stem is part of a first conductive stem structure that includes a first cylinder that is positioned in a cavity of the outer casing.

Example 55: The gun tube of example 51, wherein the second conductive stem is part of a first conductive stem structure that includes a second cylinder that is positioned in a cavity of the outer casing.

Example 56: The gun tube of example 54, wherein the cavity includes a conductive core, and a spring is positioned between the first conductive stem structure base and the conductive core.

Example 57: The gun tube of example 56, wherein the cavity includes a conductive core, and a spring is positioned between the second conductive stem structure base and the conductive core.

Example 58: The gun tube of example 45, wherein the plunger has an outer casing and a compressible metal clip positioned on the outside surface, the metal clip configured to provide an electrical ground for the plunger.

Example 59: The gun tube of example 45, wherein there is a through hole in the first conductive stem.

Example 60: The gun tube of example 45, wherein there is a through hole in the second conductive stem.

Example 61: The gun assembly of example 45 or 51 that further includes an insulating barrel connector mounted to the second stem.

Example 62: The gun tube of example 45, wherein the plunger further comprises an outer casing and a driver head on a first end or a second end of the outer casing.

Example 63: The gun tube of example 16, wherein the collar includes one or more apertures, and each aperture includes a grounding mechanism to ground the gun tube when positioned inside of an outer casing.

Example 64: The gun tube of example 63, wherein each of the grounding mechanisms is a ball and plunger unit.

Example 65: The gun tube of example 63, wherein each grounding mechanism has a first, outwardly-biased position and a second, contracted position.

Example 66: The gun tube of example 65, wherein the distance between the first, outwardly-biased position and the second, contracted position from 0.010″ to 0.080″.

Example 67: The gun tube of example 1 that includes at least one rotatable end plate that is rotatable to a plurality of indexed positions, wherein the end plate is attached to one of the one or more weights.

Example 68: The gun tube of example 67 that includes one end plate at the first end of the gun tube.

Example 69: The gun tube of example 68 that includes a second rotatable end plate that is rotatable to a plurality of indexed positions, wherein the second end plate is attached to the one or more weights.

Example 70: The gun tube of example 69, wherein the first rotatable plate includes a plurality of indexed positions, and the second rotatable plate includes the same plurality of indexed positions.

Example Set 3

Example 1: A double-wire feed through with ground (DWG) comprising:an outer casing comprised of insulating material, the outer casing having a first end and a second end;a first conductive stem extending outward from the first end of the outer casing, the first conductive stem having a first, extended position and a second, contracted position.

Example 2: The DWG of example 1 that further comprises one or more grounding legs attached to and extending outward from the outer casing.

Example 3: The DWG of example 2 that includes two grounding legs, a first grounding leg and a second grounding leg.

Example 4: The DWG of example 3, wherein the first grounding leg is on one side of the outer casing and the second grounding leg is on the opposite side of the outer casing.

Example 5: The DWG of example 1 or 2, wherein the outer casing further comprises one or more recesses, and each of the one or more recesses is configured to receive a grounding leg when the grounding leg is compressed.

Example 6: The DWG of any of examples 1-5 that further includes a second conductive stem opposite the first conductive stem and an insulating sheath that connects one or more wires to the second conductive stem.

Example 7: The DWG of any of examples 1-6 that further includes a conductive core and a spring between the conductive core and the first conductive stem, wherein the spring is configured to bias the first conductive stem to its first, extended position.

Example 8: The DWG of example 7 that further includes a second conductive stem opposite the first conductive stem and an insulating sheath that connects one or more wires to the second conductive stem.

Example 9: The DWG of any of examples 1-8, wherein the distance between the first, extended position and the second, contracted position is from 0.150″ to 1.250″.

Example 10: The DWG of example 7, wherein the spring has a compressive force from 5 lbs. to 15 lbs.

Example 11: The DWG of example 7, wherein the spring has a compressive force from 2 lbs. to 20 lbs.

Example 12: The DWG of example 7, wherein the spring has a compressive force from 5 lbs. to 30 lbs.

Example 13: A double-wire feed through with ground (DWG) comprising:an outer casing comprised of insulating material, the outer casing having a first end and a second end;a first conductive stem extending outward from the first end of the body, and a second conductive stem opposite the first conductive stem; andone or more grounding legs attached to and extending outward from the outer casing.

Example 14: The DWG of example 13 that includes two grounding legs.

Example 15: The DWG of example 13 that further includes an insulating sheath that connects one or more wires to the second conductive stem.

Example 16: The DWG of example 1, wherein the insulating material comprises plastic.

Example 17: The DWG of example 13, wherein the insulating material comprises plastic.

Example 18: The DWG of example 2, wherein each of the one or more grounding legs extends outward from the outer casing by 0.050″ to 0.250″.

Example 18: The DWG of example 13, wherein each of the one or more grounding legs extends outward from the outer casing by 0.050″ to 0.250″.

Example 20: A sub-assembly having a first end with a first opening, a second end with a second opening, and a central bore between the first opening and the second opening, and the DWG of example 1 positioned in the central bore and configured so the first, conductive stem is positioned at least partially in the first opening.

Example 21: The sub-assembly of example 20, wherein the first opening has a surface, and the central bore has a surface, and that further includes a dart retainer that surrounds at least part of the first conductive stem and that contacts the surface of the central bore.

Example 22: The sub-assembly of example 21, wherein the dart retainer has a first section with a first diameter, a second section with a second diameter, and a retainer opening therethrough, and the first stem is positioned in the retainer opening, and the first section contacts the surface of the central bore, and the second section contacts the surface of the first opening.

Example 23: The sub-assembly of example 21 or 22, wherein the dart retainer is comprised of silicone rubber.

Example 24: A sub-assembly having a first end with a first opening, a second end with a second opening, and a central bore between the first opening and the second opening, and the DWG of example 13 positioned in the central bore and configured so the first, conductive stem is positioned at least partially in the first opening.

Example 25: The sub-assembly of example 24, wherein the first opening has a surface, and the central bore has a surface, and that further includes a dart retainer that surrounds at least part of the first conductive stem and contacts the surface of the central bore.

Example 26: The sub-assembly of example 25 or 26, wherein the dart retainer has a first section with a first diameter, a second section with a second diameter, and a retainer opening therethrough, and the first stem is positioned in the retainer opening, and the first section contacts the surface of the central bore, and the second section contacts the surface of the first opening.

Example 27: The sub-assembly of example 25, wherein the dart retainer is comprised of silicone rubber.

Example Set 4

Example 1: An end fitting comprising:a first end and a second end;a bearing housing that includes ball bearings, the bearing housing having a bearing opening;a support having a first portion with a first diameter and a second portion with a second diameter that is greater than the first diameter, wherein the bearing housing is positioned on the first portion with the bearing opening surrounding at least part of the first portion; andan end contact comprising a housing, a first end having a conductive stem, and a second end that comprises an electrical contact, the second end having a first, extended position and a second, contracted position.

Example 2: The end fitting of example 1, wherein the end contact is biased to the first, extended position.

Example 3: The end fitting of example 1 or 2, wherein electricity can be conducted through the end contact.

Example 4: The end fitting of any of examples 1-3, wherein the end contact further comprises a housing and one or more frangible elements extending outwardly from the housing.

Example 5: The end fitting of example 4, wherein the housing and the one or more frangible elements are comprised of plastic.

Example 6: The end fitting of example 4 or 5, wherein the one or more frangible elements are a plurality of tabs.

Example 7: The end fitting of example 6, wherein the one or more frangible elements are two tabs.

Example 8: The end fitting of example 6, wherein each of the plurality of tabs extend outward from the body by 0.070″ to 0.125″.

Example 9: The end fitting of example 6, wherein each of the plurality of tabs is from 010″ to 0.080″ thick.

Example 10: The end fitting of example 8, wherein each of the plurality of tabs is from 0.010″ to 0.080″ thick.

Example 11: The end fitting of example 2 that further includes a spring on the end contact.

Example 12: The end fitting of example 11, wherein the spring is on a first portion of the end contact.

Example 13: The end fitting of example 12, wherein the support further includes one or more frangible elements and the spring is retained between a central portion of the end contact and the one or more frangible elements.

Example 14: The end fitting of example 6, wherein the support has an opening that receives an end of the end contact housing that includes the plurality of tabs, and wherein the end contact has a first position in which the tabs fit through the opening and a second position in which they do not fit through the opening.

Example 15: The end fitting of example 4, wherein the one or more frangible elements break when 30 lbs. or more of explosive, outward, longitudinal, axial force is applied to them.

Example 16: The end fitting of example 4, wherein the one or more frangible elements break when 50 lbs. or more of explosive, outward, axial force is applied to them.

Example 17: The end fitting of any of examples 1-16, wherein the conductive stem includes a through hole, wherein the through hole is configured to receive one or more wires.

Example 18: The end fitting of any of examples 1-17 that further includes a wire harness assembly attached to the conductive stem, the wire harness assembly comprising an insulated wire and an insulated circular connector.

Example 19: The end fitting of example 18, wherein the insulated circular connector is a barrel crimp connector.

Example 20: An end fitting for a gun tube that comprises an end contact with a first end that includes an electrical contact having a first extended position and a second, contracted position.

Example 21: The end fitting of example 20, wherein the end contact further includes one or more frangible elements configured to break when 30 lbs. or more of explosive, outward longitudinal, axial, force is applied.

Example 22: The end fitting of example 21, wherein the one or more frangible elements are a plurality of tabs.

Example 23: The end fitting of example 22, wherein the one or more frangible elements are two tabs.

Example 24: The end fitting of any of examples 1-23 that further comprises an outer collar having an opening therethrough.

Example 25: The end fitting of example 24, wherein the electrical contact is positioned from 1/16″ to 5/16″ outside of the opening when the second end of the end contact is in its first, extended position.

Example 26: The end fitting of example 4, wherein the housing and one or more frangible elements are integrally formed.

Example Set 5

Example 1: A gun tube comprising:a body having a cavity, a longitudinal axis, a first end, and a second end;a motor connected to the first end, the motor configured to rotate the body around the longitudinal axis.

Example 2: The gun tube of example 1 that further comprises a first end fitting attached to the first end of the body.

Example 3: The gun tube of example 2 that further comprises a second end fitting attached to the second end of the body.

Example 4: The gun tube of example 1 that further comprises a sensor configured to detect the location of the explosive charges.

Example 5: The gun tube of example 3, wherein the sensor comprises an accelerometer.

Example 6: The gun tube of example 3, wherein the sensor comprises one or more of an accelerometer, a magnetometer, and gyroscope.

Example 7: A system comprising the gun tube of example 6 and a motor control remote to the gun tube, the motor control configured to operate the motor.

Example 8: The system of example 7, wherein the motor control is one of a computer and a cell phone.

Example 9: The system of example 7 that further includes a receiver for receiving transmissions sent by the sensor.

Example 10: The system of a claim7, wherein the motor control is configured to be operated by a human operator.

Example 11: The system of a claim7, wherein the motor control is configured to be operated by a machine operator.

Example 12: The gun tube of example 1, wherein the at least first end fitting comprises:an outer collar;a bearing housing that includes ball bearings and a central opening; anda support having a first portion with a first diameter and a second portion with a second diameter that is greater than the first diameter, wherein the bearing housing is positioned on the first portion and the central opening surrounds at least part of the first portion, and the outer collar is fastened to the support.

Example 13: The gun tube of any of examples 1-12 that further comprises one or more charge openings configured to receive an explosive charge.

Example 14: The gun tube of example 13 that further comprises one or more explosive charges in the one or more charge openings.

Example 15: The gun tube of any of examples 1-14 that further comprises one or more clip openings configured to receive charge clips.

Example 16: The gun tube of example 15 that comprises one or more clips in the one or more clip openings.

Example 17: The gun tube of example 2, wherein the first end fitting includes a first end contact having a first, extended position and a second, contracted position, and that also comprises a second end fitting having a second end contact including a first, extended position and a second, extended position.

Example 18: The gun tube of example 12, wherein the outer collar has one or more openings, wherein at least one of the one or more openings contains grounding hardware biased to a first, extended position, and that also has a second, contracted position.

Example 19: The gun tube of example 2 or 17, wherein the first end fitting comprises an end contact having a first end that comprises a stem, the stem being positioned inside of the cavity, and the end contact having a second end, the second end comprising an electrical contact that is positioned outside of the body.

Example 20: The gun tube of example 19, wherein the end contact is configured to transmit electricity therethrough.

Example 21: The gun tube of example 2, wherein the first end fitting comprises a first end contact that includes a housing and one or more frangible elements extending outwardly from the housing.

Example 22: The gun tube of example 21 that further comprises a second end fitting that includes a second end contact having a housing and one or more frangible elements extending outwardly from the housing.

Example 23: The gun tube of example 21, wherein the housing and frangible elements are comprised of plastic and the frangible elements are configured to break away from the housing upon the application of explosive, outward axial force caused by explosion of one or more explosive charges in the gun tube.

Example 24: The gun tube of example 17, wherein the first end contact is biased towards the first, extended position.

Example 25: The gun tube of example 24, wherein the second end contact is biased towards the first, extended position.

Example 26: The gun tube of example 24 that further includes a spring on a housing of the first end contact, the spring configured to bias the first end contact to the first, extended position, and the spring configured to compress when the first end contact moves to its second, contracted position.

Example 27: The gun tube of example 26 that further includes a spring on a housing of the second end contact, the spring configured to bias the first end contact to the first, extended position, and the spring configured to compress when the first end contact moves to its second, contracted position.

Example 28: The gun tube of example 17, wherein the distance between the first, extended position and the second, contracted position of the first end contact is between 0.150″ and 1.250″.

Example 29: The gun tube of example 28, wherein the distance between the first, extended position and the second, contracted position of the second end contact is between 0.150″ and 1.250″.

Having thus described different embodiments, other variations and embodiments that do not depart from the spirit of this disclosure will become apparent to those skilled in the art. The scope of the claims is thus not limited to any particular embodiment, but is instead set forth in the claims and the legal equivalents thereof. Unless expressly stated in the written description or claims, the steps of any method recited in the claims may be performed in any order capable of yielding the desired product. No language in the specification should be construed as indicating that any non-claimed limitation is included in a claim. The terms “a” and “an” in the context of the following claims are to be construed to cover both the singular and the plural, unless otherwise indicated.