US3177808A

US3177808A - Bore hole perforating apparatus

Info

Publication number: US3177808A
Application number: US95375A
Authority: US
Inventors: Harrold D Owen
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-03-13
Filing date: 1961-03-13
Publication date: 1965-04-13
Anticipated expiration: 1982-04-13

Description

April 13, 1965 H. D. OWEN 3,177,808

BORE HOLE PERFORATING APPARATUS Filed March 13, 1961 2 Sheets-Sheet 1 FIG. I

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INVENTOR. HARROLD D. OWEN f 4%f/1 L ATTORNEY April 13, 1965 H. D. OWEN 3,177,808

BORE HOLE PERFORATING APPARATUS Filed March 15, 1961 2 Sheets-Sheet 2 INVENT-OR. HARROLD D. OWEN ATTORNEY United States Patent 3,177,863 BQRE HGLE PERFGRATIN G APPARATUS Harrold 1). Owen, 4390 Lanark, Fort Worth, Tex. Filed Mar. 13, 1961, Ser. No. 95,375 6 Claims. at. 102-20 My invention relates to bore hole perforating apparatus, and more particularly to perforating apparatus of the type utilizing shaped charges. The invention is especially concerned with the structure and arrangement of shaped charge units and carrying assemblies.

In oil well production, after a well is drilled and cased, it is perforated at the expected zone or zones of production in order to allow oil to flow from the earth formation through the casing cement and easing wall into the well. Each individual perforation is made by the firing of a single shaped charge unit. Since it is desirable to have a number of perforations in each producing zone, the shaped charge units are always arranged in groups on some sort of charge carrier device. Although numerous types and arrangements of shaped charge units and carrier devices have been devised in the prior art of which I am aware, all of them are subject to some shortcomings and fall short of the ideal.

For convenience herein, the phrase shaped charge unit may be defined as a single and complete shaped charge, including the charge body or housing, the cap or body front and closure, the explosive material or charge, and the liner. The phrase shaped charge carrier may be defined as a single unitary structure adapted for the mounting or carrying of a plurality of shaped charge units. The phrase shaped charge gun may be defined as a single shaped charge carrier with a plurality of shaped charge units mounted on it. The phrase shaped charge gun assembly may be defined as simply a plurality of shaped charge guns linked together. For further convenience, the above defined phrases may at times herein be referred to as charge unit, carrier, gun, and gun assembly, respectively.

It takes a combination of several important attributes to make a shaped charge gun assembly which will approach the ideal. A good gun assembly should, when fired, produce as little debris as possible, since debris resulting from firing a poor gun assembly can clog the well and, in some cases, seriously interfere with various production operations. Some types of gun assemblies will leave so-called carrots in the earth formation perforation. These carrots are the remains of the charge unit liner which is forced into the perforation by the action of the shaped charge. The carrots can interfere with the free flow of oil through the earth formation perforation. The best way to prevent formation of carrots is to have the charge units exposed to the well fluid. A good gun assembly should not have carrot formation tendencies. When a gun assembly is fired to perforate a well production zone, it is most desirable to have some way of determining which charge units fired and which did not. A god gun assembly should provide thisinformation in a positive form. In addition, a good gun assembly should be simple, light weight, versatile, economical to manufacture, and easy to load and assemble. A good gun assembly should also be capable of readily negotiating the well bore, pipe, casing, or tubing, without getting stuck.

The' broad object of my invention, accordingly, is to provide an improved shaped charge gun and gun assembly. Stated more specifically, the object of my invention is to provide a shaped charge gun assembly which shall have all of the attributes of a good gun assembly as outlined above to the maximum possible degree.

In accordance with my invention, the shaped charge carrier may be simply a straight metal strip or strip body "ice having a plurality of openings centered at spaced intervals along its length for receiving charge units, and provided at its ends with linking joint elements. In one form of the invention, the strip body may be a straight shallow chan nel member having sufficient structural strength to prevent disintegration and having sufiicient rigidity to assure retention of desired charge unit orientation. The channel member will have an opening centered in the channel for each shaped charge unit, with the openings being spaced so as to give the desired perforation spacing. Each charge unit preferably will have a body portion and a cap portion. Each charge cap portion is arranged to protrude through a carrier opening and means are provided to lock the cap onto the carrier. When the charge units is detonated, it perforates the cap, and since the cap remains locked onto the carrier, and since the carrier is retrieved, there is a positive indication as to whether or not each charge unit fired. The charge cap will'be made of nonfrangible material, while the charge body will preferably be made of frangible material. The charge cap is prefer-ably metal, for example, almuinum. The charge body may be either frangible metal or other frangible material such as plastic or glass. As many charge guns as desired may be linked together to make a charge gun assembly. In one form of the invention, the charge gun assembly is made up of charge guns all facing the same direction. If desired, some of the charge guns can be fixed in one direction, and others in the opposite direction. In still another form of the invention, one or more charge guns may be arranged to fire in a first direction, and others arranged to fire in directions displaced and 270 from the first direction. In each case, the charge gun linkages are of a type allowing swiveling or pivoting action about two transverse axes 90 apart, but allowing no twist action about the gun assembly longitudinal axis, since a twist action would upset the charge orientation. The specific arrangements for accomplishing the above constitute some of the features of my invention and will be hereinafter fully described.

For a more complete understanding of my invention and for further objects and advantages thereof, reference may now be had to the following description taken in accordance with the accompanying drawings, forming a part of this application, in which:

FIGURE 1 is a schematic rear elevational view of a shaped charge gun assembly in -accordance with a preferred embodiment of my invention;

FIGURES 2, 3, and 4, respectively, are schematic fragmentary rear, side and front elevational views showing details of a portion of a shaped charge gun and a linkage arrangement;

FIGURE 5 is a schematic fragmentary side elevational view, partly in section, showing a shaped charge unit mounted on a carrier;

FIGURE 6 is a schematic perspective view showing details of the linkage of FIGURES 1-4;

FIGURE 7 is a schematic side elevational view of the male linkage element of FIGURE 6;

FIGURES 8 and 9, respectively, are schematic frag mentary front and rear elevational views showing charge unit caps and carrier after a gun has been fired and retrieved;

FIGURE 10 is a schematic elevational view showing a shaped charge gun assembly in accordance with another embodiment of my invention; and

FIGURE 11 is a schematic fragmentary perspective view showing details of the linkage of the type used in the gun assembly of FIGURE 10. i

In FIGURE 1 there is shown a shaped charge gun assembly 11 made up of a plurality of shaped charge guns 13. Adjacent chargeguns 13 are held together by a linkage 15. The upper linkage of the assembly 11 may be fixed to conventional cable suspension and detonating apparatus (not shown). Conventional prima cord 17 is threaded through each charge unit opening 19 provided for that purpose. Each charge unit carrier is simply a straight shallow channel member 21 having a plurality of spaced openings 23 centered on the channel web along its length. The channel material has suflicient structural strength to provide rigidity so as to maintain the charges in predetermined orientation relation and to prevent disintegration and undue deformation upon firing, so that the assembly may be retrieved intact except for the charge unit body 25, thecharge 27, liner 29 and prima cord 17. The channel width is preferably just greater than the charge body diameter, and the channel sides 31 are just high enough to provide requisite rigidity. Channel stock made of steel having thickness has been found satisfactory for the carrier. Each carrier 21 may have any desired length, but is preferably made sufiiciently short to enable negotiation of the gun assembly through the well pipe, taking into account the pipe crooks and bends that may be encountered. A typical carrier length may be approximately inches, allowing for the mounting of four charge units on 6 inch centers, plus additional length necessary to accommodate the linkage elements. The channel openings 23 are preferably circular with a diameter sufiiciently larger than that of the protruding portion of the cap to allow for easy assembly with loose manufacturing tolerances.

As best shown by FIGURE 5, each shaped charge unit 26 has a body or housing 25, a shaped charge 27, a liner 29, and a cap 33. The charge body has a cylindrical portion 35 closed at one end by an integral conical portion 37. The cylindrical portion 35 has a reduced outer diameter in the region of the body open end. The shaped charge 27 is formed within the body interior with a conical cavity in its front face, the cavity axis being common with the body cylindrical portion axis. The charge liner 29 is in the shape of a cone designed to conform to the charge face. The charge body 25 is provided with an integral cylindrical projection centered on the charge body conical portion 37 and having a transverse cylindrical opening 19 adapted for receiving prima cord 17. The charge cap 33 has a cylindrical portion 39 merging with a frusto-conical portion 41 which in turn terminates in a cylindrical projection 43 which is threaded at its outer end portion. The inner surface of the short cylindrical portion 39 of the cap is sizedto mate with the reduced diameter portion 45 of the body 25. A sealing gasket 47 is provided for sealing the cap 33 onto the body 25. The cap interiouis provided with a cylindrical cavity 49 so as to make the cap end wall 51 easy to perforate. To assemble a charge unit 26 onto a carrier 21, it is only necessary to insert the cap threaded cylindrical, projection 43 through the charge carrier opening 23, and thread a lock nut 53 onto the projection 43, pulling the cap 33 snugly and rigidly against the Web of the carrier 21.

After the charge units have been assembled onto the carriers, a plurality of charge guns may be linked together to make up a shaped charge gun assembly. One form of linkage which has been found very satisfactory is that shown by FIGURES 2, 3 4 and 6. As shown in FIG- URE 6, the linkage 15 is made up of a male member 55 and a female member 57. Both themale and

female linkagermembers

55, 57 have shank portions 59 in the form of a rectangular plates of width substantially equal to that of the carrier channel web. The male portion 55 has a head ortongue 61 in theform of awafer, the faces of which are parallel to the shank faces. A neck 63 is integral at one end with the head 61 and at the other'end with the juncture of the head and shank forming a should der 69. The female linkage head'portion 67 has a central circular opening 71 which merges with a channel 73 opening which extends from the circular opening to the head outer face. In assembly, the head or tongue 61 of the male member makes a loose fit within the circular opening 71 of the female member head, and the male member neck 63 extends within the channel opening 73 of the female member head with side clearance. The male member head 61 has a transverse slot opening 75 centered between its faces. In assembly, this slot opening receives a pin 77 which is carried by the female portion head 67 and which extends. diametrally of the circular opening 71 and transversely of the linkage memben 5 7. The pin diameter is made substantially equal to the depth of the slot 75, but the slot width is much greater than its depth. Each linkage member shank 59 is provided with a threaded opening 79 at its approximate center. 'In assembly, each shank 59 is clamped within the channel at the end of a respective carrier 21 by a respective stud 81. The fit of the shank 59 in the channel and the

shoulder

65, 69 with the end of the channel holds each

linkage member

55, 57 rigid relative to its respective carrier 21. Thus, when assembled, the linkage of FIGURE 6 allows limited freedom of movement about the axis .of the pin 77 (see FIGURE 3) and limited sideways movement about a transverse axis displaced 90 from the pin axis (see FIGURE 2), but there can be no twisting movement about the linkage longitudinal axis. This allows shaped charge gun assembly to negotiate crooks and bends in the well pipe while maintaining desired charge unit orientation.

The shaped charge gun assembly shown by FIGURE 10 may be identical with that of FIGURE 1, except for the linkage members. For simplicity, corresponding parts in the drawings have been given the same reference numerals. Although the carriers 21 of FIGURE 10 show only two charge units 26 each, they may have more if desired. The linkage members 83 of FIGURE 10 have the same purpose as those of FIGURE 1, namely, to allow relative pivoting movement of adjacent carriers about two transverse axes, but no twisting movement about the gun assembly longitudinal axis. In addition, however, the linkages of FIGURE 10 are are designed to permit the guns to be oriented 90 apart. Details of the linkages of FIGURE 10 are shown by FIGURE 11. As seen from FIGURE 11, the linkage 83 is simply a single short angle member having a first side 85 displaced from a second side 87. The first side 85 is pivoted near its end portion tothe end portion of one carrier 21 by means of a bolt and nut, while the second side 87 is also pivoted near its end portion to an adjacent carrier by means of a bolt and nut 91. The width of each

side

85, 87 of the linkage member 83 is made less than that of the carrier channel web to permit limited motion about the respective pivot. axis. Each

side

85, 87 of the linkage member 83 is inwardly tapered to the other side at the end portion away from the side pivot end. Thus, the links age 83 allows relative movement of adjacent carriers 21 about two transverse axes, but does not permit any twisting motion about the gun assembly longitudinal axis. The linkage 83 also .acts to orient adjacent carriers 90 apart.

;It willbe apparent from the foregoing that I have provided shaped charge gun and. gun assemblies which are essentially free of debris, since the entire assembly is retrieved except for the charge unit body portion and the prima cord. When the charge unit body is made of frangible material, it will break up into very. smalljpieces upon charge detonation. Also, the gun assemblies are entirely open so that debris can fall free without any danger of clogging the gun assembly. Because the gun assemblies of my invention keep the charge units exposed to the well fluid, the'tendency toward carrot formation is minimized. Since the charges all perforate the caps, and the caps remain fixed to the carrier which is retrieved, there is provided a positive indication in each case as to whether or not a particular charge unit performed its intended perforating function. Further, the gun assemblies of my invention are capable of negotiating crooks and bends in the Well pipe while maintaining desired charge orientation. In addition, the gun assemblies of my invention are simple, light in Weight, versatile, economical to manufacture, and easy to load and assemble.

The foregoing disclosure and the showings made in the drawings are merely illustrative of the principals of my invention, and are not to be interpreted in a limiting sense.

I claim:

1. A shaped charge gun for perforating in bore holes comprising a plurality of shaped charge units each having a front end closure including a threaded cylindrical front end portion merging with a shoulder, a carrier in the form of a rigid elongated member having a plurality of spaced openings therein, with each charge unit being disposed on said carrier With said front end closure protruding through a respective opening, and a nut engaging each said threaded portion and bearing on said member for fixing said respective charge unit to said member, with said charge unit shoulder bearing on said member on the side opposite said nut.

2. A shaped charge gun for perforating in bore holes comprising a plurality of shaped charge units each having a non-frangible front end portion arranged to be perforated by firing of said unit, an open faced carrier member having a plurality of spaced openings therein, and means fixing each said charge at said front end portion to said member at a respective opening thereof.

3. A shaped charge gun for perforating in bore holes comprising an open carrier member having a plurality of openings therein, a plurality of shaped charge units each having a body and a non-frangible cap arranged to be perforated by firing of said unit, and means fixing each said cap to said carrier at a respective opening thereof for sole support of said unit by said cap and said means.

4. A shaped charge gun for perforating in bore holes comprising a plurality of shaped charge units each having a body portion and a non-frangible end closure cap sealably mounted thereon, an open carrier member having a plurality of spaced openings therein, a threaded protrusion on the end portion of each said cap remote from said body and extending through a respective carrier opening, and a nut engaging said threaded protrusion and locking said cap to said carrier.

5. A shaped charge gun assembly comprising a plurality of charge unit carriers in the form of rigid elon- 6 gated members; a linkage joining each two adjacent carriers; each linkage including a male and a female member each having a shank portion; means securing said shank portions to the end portions of respective said carriers; a neck portion integral with the shank of said male member and integral with and terminating in an enlarged tongue portion having an arcute peripheral surface; a head portion integral with the shank of said female member and providing an opening having a first portion for receiving said male member tongue portion and a second portion for receiving said male member neck portion;

said first and second opening portions having surfaces contoured to mate loosely With corresponding tongue and neck portions so as to permit relative movement of said adjacent carriers about a respective first axis perpendicular to the longitudinal axis of a respective carrier, With said movement being guided by the loosely mated tongue and first opening portion and limited by cooperation of said second opening portion with said neck; and means pivotally securing said male member to said female member for relative pivoting movement about a second axis perpendicular to said respective first axis, said last mentioned means including a slot in said tongue and a pivot shaft extending through said slot, with said slot being sized to permit said relative pivoting movement about said respective first axis.

6. A shaped charge gun for perforating in bore holes comprising a plurality of shaped charge units each having a body and a non-frangible cap sealably mounted to said body and to be perforated upon firing of said unit, an open carrier member having a plurality of spaced openings thereon, and means fixing each said cap onto said carrier at a respective said opening for sole support of said unit by said cap and said means.

References Cited by the Examiner UNITED STATES PATENTS 491,469 2/93 Carver 287 2,266,345 12/ 41 Turechek 89-1 2,756,677 7/56 McCullough 10220 2,799,224 7/57 Long 102-20 2,981,185 4/61 Caldwell 102-20 FOREIGN PATENTS 184,886 3/56 Austria.

BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL FEINBERG, SAMUEL BOYD, Examiners.

Claims

1. A SHAPED CHARGE GUN FOR PERFORATING IN BORE HOLES COMPRISING A PLURALITY OF SHAPED CHARGE UNITS EACH HAVING A FRONT END CLOSURE INCLUDING A THREADED CYLINDRICAL FRONT END PORTION MERGING WITH A SHOULDER, A CARRIER IN THE FORM OF A RIGID ELONGATED MEMBER HAVING A PLURALITY OF SPACED OPENINGS THERIN, WITH EACH CHARGE UNIT BEING DISPOSED ON SAID CARRIER WITH SAID FRONT END CLOSURE PROTRUDING THROUGH A RESPECTIVE OPENING, AND A NUT ENGAGING EACH SAID THREADED PORTION AND BEARING ON SAID MEMBER FOR FIXING SAID RESPECTIVE CHARGE UNIT TO SAID MEMBER, WITH SAID CHARGE UNIT SHOULDER BEARING ON SAID MEMBER ON THE SIDE OPPOSITE SAID NUT.