US2416077A - Well torpedo - Google Patents

Description

met Feb. 18, .1947

WELL TORPEDO Application August 13, 1943, Serial No. 498,45d 1 Claim. (01. 102F205 In well-shooting practice, difierent subterranean conditions require diflerent concentrations of 4 explosives opposite given sections of sand. Heretoiore, this situation has been met by using torpecloes that have varied in diameter in accordance with the size of the explosive charge. This naturally resulted in the distance between the wall of the well and the torpedo varying with the size of the torpedo. and it is in this space that part of the energy of the shot is dissipated. The amount of such energy dissipation depends upon the distance the shock wave must travel, so an appreciable fraction of the explosive energy may be expended before the shock strikes the sand formation when there is a relatively wide space between torpedo and well wall.

it is among the objects of this invention to eliminate most of the energy loss due to the space between the torpedo and the well well, and to hold the width of that space to a minimum regardless of the size of the explosive charge,

In accordance with this invention a well-shooting torpedo has a constant outer diameter, but it is provided with a central vertical passage the diameter of which depends upon the desired thickness of the explosive charge between the passage and the outside of the torpedo. This passage is adapted to be filled with a suitable incompressible material. such as sand or a liquid Or both, so that all of the explosive energy is directed outwardly. The outer wall of the torpedo and the wall of the central passage may be formed by outer and inner shells of metal, plastic, or other suitable material, that form between themselves an annular chamber in which the explosive is disposed. The outer shells for these torpedoes are all the same size. but the inner shells have different diameters so that the explosive-receiving chambers can be varied in capacity for charges of diiierent concentrations.

The invention is illustrated in the accompanying drawing in which Fig. 1 is a plan view' of my torpedo with the top partly broken away; Fig. 2

Fig. 1; Fig. 3 is a fragmentary vertical section through a modification of the invention; and Fig. 4 is a vertical section through another modification in which a solid or self-supporting explosive charge is used.

Referring to Figs. 1 and 2 of the drawing, the side wall of a well-shooting torpedo is formed by a cylindrical metal shell I of the maximum diameter that can be used within safety limits. For all torpedoes that are to be used with well holes of the same diameter, the outer shells are the same size so that there will always be the same minimum annular space between the torpedo and well well. The lower end of the shell is closed by an inverted conical member 2 the lower end of which is provided. with a cylindrical extension 3 closed at its bottom. Rigidly mounted in the upper end of this extension is a nut at having a concave top. Inside the shell and concentric therewith there is a smaller inner shell 6 of substantially the same length as the outer one. The lower end of the inner shell is closed by an inverted conical member 7? which rests on conical member 2. The two shells are held together by a screw 8 projecting from the lower end of cool cal member '5 into nut l. B this means the two shells are screwed together, thereby permitting an inner shell of any desired diameter to be quickly mounted in fixed position in the outer shell. Of course, there are other ways by which the two shells can be connected, such as by welding or solderingthem together.

The two shells having about the same length,

I and the inner shell being materially smaller than is a vertical section taken on the line 11-11 of the outer one, the top of the inner shell lies below the top of the outer one to which it is connected by an inverted frusto-conical ring it having substantially the same degree of taper as conical member 2. This ring may be welded or sol clered to the two shells. Due to the tapered lower end of the torpedo it can more readily be lowered into a well without interference from burrs on the well casing or from joints and other projections. The concave upper end of the torpedo per-- mits two or more torpedoes to be nested on of one another in a well. For lowering the torpedo into a well its upper end may be provided with a bail or the like (not shown) to which line can be attached.

The annular space between the two shells formsa chamber for an explosive it with which it is filled. The explosive charge may be any suitable material, but the annular chamber is particularly adapted to receive a liquid explosive, such as nitro-glycerine, that can be poured into the ch t.

her through openings ii in top ring 9. To

vent some of the force oi the enplosioniir'om r ing expended inwardly, the passage through i inner shell is filled with substantialhv lncoml sible material such as a liquid, a solid example), or both, or other type material. The drawings show the inner. filled with sand it. If desired, however.

asi es? ner shell can be left empty, and it will become filled with the liquid standing in the well when the torpedo is lowered into the well.

It will be seen that although the outer shells of my torpedoes can always have the same diameter, the concentration of the explosive can be varied by having on hand a stock of inner shells of diiferent diameters and using one that will form a charge-receiving space of the desired re stricted capacity. Thus, the larger the inner shell the smaller the explosive charge. Nevertheless, in every case the explosive is always located the same distance from the wall of the well and can therefore be held right next to the formation where its energy should be expended.

Another advantage or" always having an outer shell of maximum diameter is that it prevents the torpedo from becoming tilted in the well with a resulting unsymmetrical shooting action. With the shell nearly as large as pedo can not become disposed in a lopsided position in the well.

Although the drawing shows the outer and inner shells concentrically arranged, it will be understood that if it is desired to shoot the formation harder in one direction than another, the inner shell can be mounted off-oenter relative to the outer one to give the charge-recoil! ing chamber a varying width. Eccentric mounting of the inner shell is illustrated in Fig. 3.

In the modification shown in Fig. 3 the upper ends of the shells are connected in the same way as in Figs. 1 and 2, but the lower ends are joined in a different manner. Thus, the bottom of the outer shell lli is secured to the top of an inverted, eccentric frusto-oonical ring it of substantially the same size andshape as the top ring. The bottom of the inner shell ll is open and is welded or soldered to the lower end of ring to form an annular chaoiher which the explosive is retained. its in i previous eonbodiment, any size inner shell nit-1y be used, depending upon the size of explosive charge desired. The inner shell is shown as being mounted eccentrically of the outer shell so that the explo sive chamber is wider at one side of the torpedo than at the opposite side. However, the two shells could be concentrically mounted if desired. This type of torpedo is especially designed for wells in which it will be immersed in a body of liquid, such as water or oil, standing in the well. Under such conditions it is not necessary to fill the central passage through the torpedo with an incompressible material, because when the torpedo is placed in the well the liquid therein will fill the inner shell.

If a solid, sell-supporting explosive is used, the two shells are not necessar explosive can he pro-cast to sired external and internal central passage can then he tilled the like. This modification 2 d where the explosive p it having an outer diameter r imum size, and having a central the well hole, the tor- 22 through it of the size necessary to leave the desired amount of explosive in the r This passage may he coaxial with the set for unbalanced shooting as mentioned above. The passage may be packed lull of sand or other dry, incompressible material to prevent the roe of theexploslonfrom acting inwardly. or it insremain empty until filled with liquid staudln in a well into which it is lowered. If illlecl lit,- iore being lowered, the filling material can held in place by plugs or the like in the ends the passage. Like the inner shell of Figs. 32' 3, the size of central passage can he alter the concentration of esplosive.

The way in which the torpedoes are detonated depends upon the type of explosive used as will he evident to those skilled in the art. As the 13, nor of detonation has nothing to do with. invention, there is no illustration of it.

According to the provisions of the patent statutes, 1' have explained the principle and c0nstruction of my invention and have and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the ap-- pended claim, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

well-shooting torpedo adapted to be lowered into a well, comprising a rigid outer cylindrical vertical shell having a diameter substantially as great as that of the well to be shot, rigid cylindrical vertical shell mounted in fixed position inside outer shell and spaced therefrom to provide an annular charge-receiving space hetwecn the shells, the inner shell being large enough to restrict the size of sci" space to the irci capacit means closing hotto u of said a; and the bottom oi. the inner shell, lllf lnsilw charge filling said and inert suhstantially incompressible material filling the inshell to form a barrier to lateral pressure dissipation when the torpedo is discharged.

SAMUEL T.

illustrated The following references are of record in the die of this patent: Ullllnii STATUES Number Name llllfiliil 145,612

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