US2833214A - Gun perforator - Google Patents

Description

L. SPENCER GUN PERFORATOR 2 Sheets-Sheet 1 Filed Aug. 18 1951 VENTOR.

L. SPENCER GUN PERFORATOR May 6, 1958 2 Sheets-Sheet 2 Filed Aug. 18 1951 NVENTOR.

GUN PERFORATOR Lloyd Spencer, Los Angeles, Calif., assignor of sixty-six and two-thirds percent to Thomas C. Baun'on, Alta" dena, Calif., and thirty-three and one-third percent to John D. Chesnut, Newport Beach, Calif.

Application August 18, 1951, Serial No. 242,488

11 Claims. (Cl. 102-40) My invention relates to gun perforators, more particularly to single use or expendable gun perforators, and included in the objects of my invention are:

First, to provide a gun perforator which utilizes hollow or shaped charges to effect penetration of a surrounding well casing or formation, and on being fired is destroyed.

Second, to provide a gun perforator of the expandable type wherein all expenses incidental to its manufacture and use are reduced to a particularly low minimum; for not only is the cost of the material from which it is fabricated reduced to a minimum, but also the method of manufacture, assembly and subsequent handling, andloading involves a minimum expense.

Third, to provide a hollow charge expendable gun perforator which utilizes a liquid explosive, or at least an initially liquid explosive completely filling the cavities of the gun perforator, with the exception of the hollow charge cells, and wherein the Walls of the gun perforator are yieldable to submergence pressures so that the explosive is subjected thereto and no appreciable pressure differential exists across the hollow charge cells to complicate problem of sealing of these cells in the gun perforator.

Fourth, to provide an expendable gun perforator having novel complementary members of sheet material which define the detonation cavities and passages of the gun perforator and hold the hollow charge cells in place.

With the above and other objects in view as may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figure 1 is a fragmentary partially elevational, partially sectional view of one form of my gun perforator.

Fig. 2 is a transverse sectional view through 2'2 of Fig. 1.

Fig. 3 is a transverse sectional view through 33 of Fig. 1.

Fig. 4 is an enlarged transverse sectional view through 4--4 of Fig. 1.

Fig. 5 is a fragmentary longitudinal sectional view through55 of Fig. 4.

Fig. 6 is an enlarged fragmentary sectional view through 66 of Fig. 4.

Fig. 7 is a composite transverse sectional view in the same plane as Fig. 4 showing the complementary body members separated from each other.

Fig. 8 is a fragmentary elevational view of one of the body members taken along the line 8-8 of Fig. 7.

Fig. 9 is a fragmentary edge view of one of the body members taken along the line 9-9 of Fig. 7.

Fig. 10 is a transverse sectional view similar to Fig. 4 showing a modified form of my gun perforator.

My gun perforator includes complementary body members: I formed of sheet material such as light gage metal. In order to dispose the several gun units symmetrically, for example, 120 apart. Each gun body member may consist of a sheet strip folded centrally to form leaves in 120 relationship. At the juncture of the leaves each 2,833,214 Patented May 6, 1958 member is provided with a channel which, when the three members are positioned so that their leaves are complementary, together define a longitudinal central passage 2.

Each body member is provided with a series of 'semiconical, or semi-ovoid depressions, which when the leaves are mated define radially outwardly directed detonation chambers 3. The apices of the chambers 3 communicate with the passage 2 through ports 4 formed in complementary leaves.

Each detonation chamber is adapted to receive ahollow charge cell 5. Each cell comprises a conical member 6 adapted to extend into the detonation chamber, and a dome shaped cap 7 covering the conical member. The conical member and cap may be provided with mating flanges 8 sealed together. The hollow charge cells are made strong enough to resist submergeuce pressures. This may be aided by pre-pressurizing the cells with carbon dioxide.

To secure the cells in place, the body members at the extremities of the detonation chambers may be provided with tabs 9 for spot welding to the flanges of the cells. The body members may be joined to each other by spotwelding; however, they may be securedby solder or even by a thin adhesive.

The upper extremities of the body members may be secured in a mandrel 10 having radial slits 11 to receive the ends of the body member. The mandrel may be provided with an external tapered screwthread and receive a screwthreaded collar 12 which cooperates therewith to clamp the split sections against the body members. ease of manufacture diametrical slits are cut and the portion thereof which does not receive a mating pair of body members is filled with a spacer 11a. The mandrel is provided with a small central bore 13 which alines with the vertical passage 2.

The mandrel is suitably attached to a weight bar 14 through which extends a conductor 15, if the gun perforator is to be electrically fired. A detonator 16 is suspended from the conductor in the bore 13 of the mandrel. The firing means per se is not part of the present inventron.

After assembly of the gun body members and hollow charge cells, and after the body members are secured in the mandrel, the entire structure is dipped or sprayed or plated with a coating 17, for example, a phenolic lacquer. Any coating material suificiently viscous, capa= ble of sealing and withstanding, at least temporarily, well temperatures and well fluids may be used. The coating completely seals the cavities of the gun perforator including the juncture between the gun perforator and the mandrel.

The gun perforator is intended to be filled with a liquid explosive, or at least an explosive which can be poured therein in a liquid state. An'example of a liquid explosive is sensitized nitromethane. TNT may be melted and poured. The liquid may be poured into the upper end of the mandrel. In order'to facilitate complete filling of the detonation cavities small slits 18 may be provided above each detonation cavity to bleed air therefrom.

The gun body members need not be strong enough to withstand submergence pressures, for the explosive filling the passage and detonation cavities prevents any collapse assuming, of course, that the explosive in a liquid or solid state completely fills the cavities divined by the gun body. amount of air or gas may be present. In such case thewalls of the gun body members yield inwardly the slight amount needed. Such yielding most readily occurs with.- in the areas of the flat sides of the slits 18. These fiat In actual practice, however, a slightsides thus constitute yieldable membranes. Because the walls of the body members and particularly the membrane areas are readily yieldable, there is no appreciable pressure differential between the interior and exterior of the gun body so that the sealing coating 17 is fully capable of excluding well fluids or preventing leakage of the explosive.

The gage thickness of the metal comprising the gun body members may be sufiiciently strong, particularly when joined together, to withstand without added protection the loads imposed incidental to lowering the gun perforator in a well bore. However, extremely thin material may be used for reasons of cost and ease of forming; if so, a filler of protective material may be cast around the gun body members. This may be any inexpensive material, high melting tar, gypsum, cement,

. or mixtures may be used, or a rubber or rubber-like coating may be applied. It is preferred that the material be sufiiciently yieldable to submergence pressures to transmit such pressures to the gun body members.

If a cast filler material is to be used to embrace the body members, an extremely weak material may comprise the gun body members; for example, papier-mache, or a similar type of material, may be employed. In-this case, as shown in Fig. 10, the body members 21 may be shaped over suitable forms to provide detonation cavities 22. In this case, the cavities of each pair of body members are shown as connected to a common longitudinal passage 23, but the arrangement shown in Fig. 4 may also be used. Because of the nature of the material, the flange and dome of each hollow charge cell may be covered by the body members as indicated by 24 so that the cells are held in place. The body members are secured by a suitable adhesive. The papier-mache is impregnated with a suitable sealer which may be :of the same character as the adhesive, for example, a phenolic lacquer or other material resistant to well fluids as well as any solvent or chemical reaction with the explosive.

The gun body members may be encased in 'a fabric sleeve which may be capable of stretching over and around the hollow charge units. The sleeve 25 is filled with suitable castible material 26, such as a high melting tar, gypsum, cement or other mixture, preferably so compounded as to be yieldable to submergence pressures.

The modified form of gun perforat-ors may be secured to a mandrel similar to the first described structure and if so, the filler material 26 may be cast around its lower end to seal against the well fluids.

This application is a continuation in part of my copending application Serial No. 3674 filled January 22, 1948, now abandoned.

Having thus described certain embodiments of my invention, I do not desire to be limited thereto, but intend to claim all novelty inherent in the appended claims.

I claim:

1. An expendable gun perforator, comprising: a pair of elongated gun body members formed of sheet material and shaped to form the complementary portions of a series of laterally expanding detonation chambers and a connected passage said body members being connected together to form a unitary structure; and a hollow charge cell closing each detonation chamber and including an end portion extending therein to define the walls of the recess in a shaped charge; said detonation chambers and passage adapted to be filled with an explosive, said body members being yieldable to submergence pressures and said cell being resistant to submergence pressures.

2. An expendable gun perforator, comprising: a pair of elongated gun body members formed of sheet material and shaped to form the complementary portions of a series of laterally expanding detonation chambers and a connected passage said body members being connected together to form a unitary structure; and a hollow chargeend portion extending therein to define the walls of the recess in a shaped charge; said detonation chambers and passage adapted to be filled with an explosive, said body members being yieldable to submergence pressures and said cell being resistant to submergence pressures, and a yieldable sealing material covering said gun body members and said hollow charge cells.

3. An expendable gun perforator, comprising: elongated body members formed of sheet material of V-shaped cross section to provide pairs of complementary leaves radiating from a common center said body members being connected together to form a unitary structure, said leaves having depressions defining complementary radially outwardly expanding detonation chambers and longitudinally connecting passages; and hollow charge cells sct into the outer ends of said detonation chambers; said detonation chambers and passage adapted to be filled with an explosive, said body members being yieldable to submergence pressures and said'cell being resistant to submergence pressures.

4.An expendable gun perforator, comprising: elongated body members formed of sheet material of V- shaped cross section to provide pairs of complementary leaves radiating from a common center said body members being connected together to form a unitary structure, said leaves having depressions defining complementary radially outwardly expanding detonation chambers and longitudinally connecting passages; and hollow charge "cells set into the outer ends of said detonation chambers; and a sealing material enveloping and sealing said body members and hollow charge cells.

5. An expendable gun perforator, comprising: a pair of elongated gun body members formed of sheet material and shaped to form the complementary portions of a series of laterally expanding detonation chambers and a connected passage said body members being connected together to form a unitary structure; and a hollow charge cell closing each detonation chamber and including an end portion extending therein to define the walls of the recess in a shaped charge; said detonation chambers and passage adapted to be filled with an explosive, said body members being yieldable to submergence pressures and said cell being resistant to submergence pressures; and a cast body structure molded around said body members and hollow charge cells sealing said cells therein.

6. An expendable gun perforator, comprising; elongated body members formed of sheet'material of V- shaped cross section to provide pairs of complementary leaves radiating from a common center said body members being connected together to form a unitary struc said sleeve, enveloping said body members, and sealing said cells therein.

7. An expendable gun perforator, comprising: a plu-' rality of longitudinally extending fins radiating from a common center, each fin including complementary members sealed together and defining longitudinally spaced radially outwardly diverging detonation chambers, said fins also defining at least one longitudinally extending connecting passage complementary portionsof said chambers and passage being formed in each member of said fin; submerged pressure resistant hollow charge cells secured in the radially outer extremities of said detonation chambers; and an at least initially liquid explosive com-' pletely filling said detonation chambers and passage and supporting the. same against collapse from submergence pressures.

8. An expendable gun perforator, comprising: a plurality of longitudinally extending fins radiating from a common center, each fin including complementary members sealed together and defining longitudinally spaced radially outwardly diverging detonation chambers, said fins also defining at least one longitudinally extending connecting passage complementary portions of said chambers and passage being formed in each member of said fin; submergence pressure resistant hollow charge cells secured in the radially outer extremities of said detonation chambers; and at least an initially liquid explosive completely filling said detonation chambers and passage and supporting the same against collapse from submergence pressures; and a coating completely enveloping said fins and sealing said hollow charge cells therein.

9. An expendable gun perforator, comprising: a plurality of longitudinally extending fins radiating from a common center, each fin including complementary members sealed together and defining longitudinally spaced radially outwardly diverging detonation chambers, said fins also defining at least one longitudinally extending connecting passage complementary portions of said chembers and passage being formed in each member of said fin; submergence pressure resistant hollow charge cells secured in the radially outer extremities of said detonation chambers; and at least an initially liquid explosive completely filling said detonation chambers and passage and supporting the same against collapses from submergence pressures; and a cast body of material bridging between said fins and sealing said cells therein.

10. An expendable gun perforator as set forth in claim 7 wherein said fins are formed of metal and are self supporting and between which well fluids may fiow when the gun perforator is lowered in a well bore.

11. An expendable gun perforator as set forth in claim 7 wherein said fins form a core; and a body of reinforcing material is cast around and between the fins.

References Cited in the file of this patent UNITED STATES PATENTS 1,298,500 I-Iardel Mar. 25, 1919 2,233,930 Witt Mar. 4, 1941 2,409,848 Greulich Oct. 22, 1946 2,418,486 Smylie Apr. 8, 1947 2,494,256 Muskat et al. Jan. 10, 1950 2,543,057 Porter Feb. 27, 1951 2,543,814 Thompson et al. Mar. 6, 1951 2,587,244 Sweetman Feb. 26, 1952

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