US2326406A - Gun perforator - Google Patents

Description

Aug. w, 1943o L. sPENcER 2,326,406

GUN PERFORATR v Filed Aug- 18 1942 2 Sheets-Sheet l Patented Aug. 10, 1943 GUN rnltrom'ron Lloyd Spencer, ALos Angeles, Calif., assigner to Lane-Wells Company, Los Angeles, Calif., a

corporation of Delaware Application August 18, 1942, Serial No. 455,259

18 Claims. (Cl. 16d-0.5)

My invention relates to gun perforators; that is, to devices designed to be lowered within Well casing for the purpose of firing bullets through the casing and provide openings for the entrance of the surrounding fluid. Among the objects of my invention a're:

First, to provide a gun perforator which doe not require electrical connection with the sur face, that is, the gun perforator may be suspended from a sand line, or even a single strand wire line, in place of the conventional conductor cable;

Second, to provide a multiple unit gun per-w forator which incorporates novel detonating or ignition means between the gun units, actuated by one gun unit to initiate the operation of the next, the gun units being arranged to bring comparatively large operating force to bear upon the detonating means so that the detonating or ignition means may be relatively insensitive and therefore make the gun safe to load and service;

Third, to provide a multiple unit gun perforator wherein the gun units are operatively connected by passageways which however are blocked by the detonating means, said means sealing in both directions against the transfer of gases from the main or bullet-propelling explosive charge in Aone unit to the main or bullet-propelling charge in the next, thereby eliminating not only any appreciable pressure loss in the associated gun units but also minimizing any erosion of such passageways;

Fourth, to provide a multiple unit gun perforator which is particularly suitable for small dimension casing or tubing such as employed in slim hole drilling, a new drilling technique rapidly assuming importance in which tubing as small as 21/2 to 3 inches is used in place of larger use of the gun perforator in connection with light inexpensive service equipmentin place of the expensive hoisting trucks now required to handle the cable alone, irrespective of the weight requirements of the gun itself; and

Seventh, to provide a multiple unit gun 'perforator which is particularly simple and economical to manufacture and service.

With the above and other objects in View, as

may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figures 1 through 6 illustrate one form of my gun perforator Figure 1 is a fragmentary elevational view of my gun perforator suspended from a single strand ca'ble and showing in connection therewith an electrically operated go-devil; l

Figure 2 is an enlarged transverse sectional v'ieW of the go-devil taken through 2 2 of Figure 1;

Figure 3 is a fragmentary longitudinal section- 'a1 view of the go-devil showing the lower portion thereof as it rests on the gun perforator,

the section being taken in the plane 3 3 of Figure 2;

Figure 4 is a fragmentary longitudinal sectional view of the gun perforator taken through casing and which necessitates guns which are less than 3 inches in diameter;

Fifth, to provide a multiple unit gun perforator wherein the gun bore occupies a major portion of the gun perforator's diameter so that for a given size of gun the maximum .bullet velocity is obtainable;

Sixth, to provide a multiple unit gun perforator wherein the smaller sizes at least are capable of being lowered on a single strand steel wire line such as used conventionally for depth measuring purposes in oil wells, such single strand wire line having only one-tenth the weight of conventional conductor cable, that is, a mere 22 to 25 pounds per thousand feet in place of the 250 to 300 pounds per thousand feet of the conventional conductor cable, thereby permitting tional view taken through 5 5 oi.' Figure 4;

and

Figure 6 is a transverse sectional view thereof l taken through 6 6 of Figure 4;

Figures 7, 8 and 9 illustrate a modified form of gun perforator in which- Figure 7 is a fragmentary elevational view thereof; Figure 8 is an enlarged transverse sectional view thereof taken through 8 8 of Figure 7; and

Figure 9 is a fragmentary longitudinal sectional view'thereof taken through 9 9 of Figure 8.

With reference iirst to the structure shown in Figures 1 through 6, my gun perforator includes a gun body I in the form of a cylindrical bar adapted to fit within the casing or tubing. 'I'he construction shown in Figures -1 through 6 is particularly designed for use in the smaller size tubing. The gun body is provided with a series` gun bore is intersected at its inner end by the.` lower inner end of a downwardly directed, sloping cartridge bore or chamber 3, the cartridge bore and its gun bore occupying a common plane so that the outer end of the cartridge bore is vertically above its corresponding gun bore and intersects the same side of the gun body, as shown in Figure 4. Each cartridge bore or chamber and gun bore forms a gun unit.

Between each cartridge bore and the gun bore of the unit above there is provided a detonator bore 4 which extends parallel to the cartridge bore and is positioned so that it intersects substantially tangentially the gun bore of the unit above. 'I'he detonator bore extends diametrically through the gun body from one side to the other. Each detonator bore is connected with its corresponding cartridge bore by a passageway which intersects the detonator bore at a point below its intersection with the gun bore.

Each gun bore 2 receives a bullet 8 which is covered by a yieldable seal cap 1, preferably shaped so that uid pressure tends to seal the cap tightly against the walls of the gun bore and prevent passage of uid backwardly around the bullet. Each cartridge bore or chamber 3 receives an explosive cartridge 8. The outer end oi.' each cartridge bore is threaded to receive a plug 9. A gasket III seals the cartridge bore at the inner end of the plug 3.

Both ends of each detonator bore 4 are enlarged and screw-threaded to receive plugs Il. Between the plugs the detonator bore receives a detonator or igniter element I2 and a iiring pin or piston I3. The detonator unit is positioned in the lower portion of the detonator bore opposite the intersection of the passage 5 therewith, while the upper end of the ring pin I3 is exposed to the gun bore of the gun unit above. The detonator bore 4, as well as the passages 5, are made as small in diameter as possible.

'Ihe detonator bore of the uppermost gun unit is intersected by a top passage I4 which intersects the detonator bore at a point corresponding to the point o! intersection of the gun bores of the umts below. The top passage I4 extends upwardly and intersects the upper end of the gun body. The gun bore of the lowermost gun unit in the gun body is intersected by a centrally located, downwardly directed bottom passage I5 which intersects the lower end oi the gun body. The upper end of each gun body is reduced in diameter and externally threaded. while the lower end oi each gun body is provided with an internally threaded socket, so that when two gun.

bodies are screwed together a continuous pessageway is formed by the registering of passages I5 and I4 from the lowermost gun unit of the upper gun'body to the uppermost detonator bore 4 of the lower gun body, as indicated by dotted lines in the lower portion oi Figure 1.

The gun body I described hereinbefore, as well as the gunbody shown in Figures 7, 8 and 9, to be described hereinafter, is interchangeably suspended from an ignition sub 2l illustrated in Figures 1 and 7. The ignition sub is provided with a downwardly inclined cartridge bore which receives an ignition cartridge 22 containing a fuse wire andis closed by a plug 23, indicated by dotted lines in Figure 1.

A passage 24 corresponding to the bottom passage Ii is provided in the lower end of the ignition sub for connection to the top passage I4 of the upper gun body. 'I'he ignition sub is adapted to be screw-threaded to a cable head 25 which is provided with suitable means (not shown) for anchoring the end oi a cable or a single strand wire line W. The cable head is provided with an insulation ring 28 which is covered in Figure 1 but which is shown uncovered in Figure 7 carries several upwardly directed contact fingers 21. The contact fingers are connected by a conductor 28 to the ignition cartridge 22 shown in Figure 7. 'Ihe conductor and mounted portions oi.' the contact ngers may be protected by friction" tape or the like, as shown in Figure 1..

Operation of the gun perforator may be mitiated by a go-devil which comprises a pair of semi-cylindrical go-devil sections 3|. 'I'he two sections are complementary and are adapted to be bolted around the wire line W by bolts 32 and dene a longitudinal guide passage 33 which accommodates the wireline. The sections are provided with battery cavities 34 and their lower ends are tapered to form complementaryfriose pieces 35 which together may be. conical inform and flt into the ared upper end of the cable head 25 as shown in Figure 3. Above the nose pieces and insulated therefrom is a contact ring 38 formed of two complementary sections electrically connected with the battery cavities of the corresponding go-devil section. The contact ring is so positioned that when the go-devil engages the upper end oi the cable head 25 contact is made with the contact ngers 21, so that electric current can be furnished to the ignition cartridge.

Operation of my gun perforator is as follows: The gun perforator is lowered into position, the go-devil assembled around the wire line and bolted. When the go-devil strikes the upper end of the gun the electrical circuit is completed through the ignition cartridge 22 which, by reason of the fuse wire therein, ignites, generating sumcient pressure to drive the iiring pin II of the uppermost detonator bore 4 against the detonator or igniter element I2 which'either burns or explodes, or both, to provide the requisite ameand pressure to ignite the corresponding cartridge 8. Upon ignition of the cartridge 8 the corresponding bullet 3 is driven from the uppermost barrel, and in doing so exposes the iiring pin of the succeeding detonator bore 4 to the explosive pressures generatedv by the cartridge 8, causing the ring pin to, act against its detonator unit, the second detonator element in turn igniting the second cartridge, and so on.

The detonator or igniter element may be a conventional detonator cap with a small charge of powder or, preferably, may comprise only a small charge of black powder or T. N. T., or other 'explosive capable of being 'set oil.' by shock alone. 'I'he forces generated in the cartridge chamber and behind the bullet are extremely high, reaching as high as 100,000 pounds per square inch; consequently the ring pin is driven against its detonating unit with a force sufficient to ignite even.relatively insensitive explosives, thus eliminating the need of the comparatively dangerous fulminate of mercury detonator, or similar conventional detonators. This is of considerable practical importance for by the use of a comparatively insensitive detonator or igniter the dangers of loading and servicing are practically eliminated.

The ring pin also serves another function; it forms a seal between the succeeding gun units so that there is little or no actual transfer of burning gases which would erode open passage- Ways between the gun units. It will be noted that the firing pin need have but very little travel, so that the quantity of gas that enters the detting unit, as well as the pressure generated by` the gun units below. The detonator unit, in firing, does not need to generate the high pressures required of the gun cartridge, but does provide a rather substantial back pressure at the time the cartridge discharges to reduce back-flow and loss of gases through the passageway 5.

Reference is now directed to the structure shown in Figures 7, 8 and 9: This structure operates substantially identical to the -previously described structure, but is made for casing of somewhat larger diameter, permitting a more compact arrangement of the gun units. In the modied structure the gun body 4| is provided with a plurality of laterally directed barrel sockets 42 which are internally threaded. At the in' ner end of each socket is a cartridge chamber 43. The sockets are preferably displaced circumferentially from each other 90. Midway between each pair of cartridge chambers 43 and in a plane common thereto is a horizontally7 extending detonator bore 44. Each detonator bore is connected to the cartridge chamber above by a passage 45 and to the cartridge chamber below by a passage 46.

Each barrel socket 42 receives a gun barrel 41 having a gun bore 48 adapted to receive a bullet 49. The bullet 49 ispreferably secured to a seal disk 50 which is adapted to be clamped between the inner end of the gun barrel and the shoulder formed at the inner end of the barrel socket 42. The inner end of the gun bore is preferably chamfered or beveled and the seal disk conforms thereto to form a frusto-conical portion so as to support the bullet against fluid pressure.

Each cartridge chamber 43 receives an explosive cartridge I. The ends of each detonator bore 4I are enlarged and screw-threaded to receive sealing plugs 52. The passages 45 and 46 are offset from each other along the axis of the detonator bore. Opposite the intersection of passage 46 the detonator bore receives a detonator element 53, while opposite the passage 55 there is placed a ring pin 54.

'I'he ends of the gun body I may be reduced in diameter so that a single size cable head and ignition sub may be used for different sizes of guns. The upper end of each gun body is externally threaded while the lower end of each gun body is provided with an internally threaded socket. A passage 55 extends from the lowermost cartridge chamber 43 to the center of the socket in the lower end of the gun body, while another passage 56 communicates from the upper end of the gun body to the rst detonator bore, intersecting at a point corresponding to the intersection of passage 45 therewith.

Operation of the structure shown in Figures 7, 8 and 9 is the same as the previously described structure, that is, the pressure generated in one cartridge chamber is utilized t0 drive the corresponding ring pin 54 against the detonator unit 53, the discharge of the detonator unit being utilized to ignite the succeeding cartridge. As in the rst described structure, the firing pin servesI as a sealing means to prevent transfer in either direction, that is, either from the upper cartridgeV chamber to=V the lower one or from the lower one to the upper one depending upon which cartridge chamber has the higher pressure, so that there occurs no appreciable reduction in powder pressure. Also, as in the first described structure, the detonator or igniter element 53 may be comparatively insensitive so that the gun may be safely handled.

The structure shown in Figures 7, 8 and 9 permits closer positioning of the gun units so that a larger number of gun units may be provided per unit length of gun perforator than in thestructure shown in-Figures 1 through 6. On the other hand, the structure shown in Figures lvthrough 6 is more adaptable to guns of smaller diameter.

Various changes and alternate arrangements may be made within the scope of the appended claims, in which it is m'y intention to claim all novelty inherent in the invention.

I'claim: l. A gun perforator comprising: a plurality of gun units; means dening passageways connecting said gun units in series; a detonator element and a ring pin both wholly within each passage-V way said firing pin being responsive to explosive gas pressure in one gun unit to actuate the succeeding gun unit.

2. A gun perforator comprising: a plurality of gun units, each including a cartridge chamber and gun bore, a cartridge for said cartridge chamber, a bullet; for 'said gun' bore; means defining passageways connecting said gun units in series a pairof removable abutments confronting said passageway; a iluid responsive firing piston in each passageway betweensaidabutments sealing against appreciable transfer of iiuid between said gun units; and ignition means also between said abutments engaged by said firing pin upon discharge of one of said gun units for initiating the discharge of the succeeding gun unit. f

3. In a multiple unit gun perforator, apparatus for discharging the units of the gun perforator in sequence, comprising: means defining a detonator chamber and passageways connecting said chamber to adjacent gun units removable abutments forming the ends of said chamber; and a captive bullet and a detonator element in each detonator chamber between said abutments, said bullet adapted to be driven against said detonator unit by the pressure generated in one of said gun units to actuate the detonator, thereby to actuate the succeeding gun unit.

4. A gun perforator comprising: a pairof gun set off by said captive bullet when said captiv` bullet is driven by pressure from th other of said gun units. i

5. A gun perforator comprising: a gun body having a plurality of cartridge bores, major gun bores and minor bores the latter communicating between a succeeding gun unit; a cartridge for said cartridge bore; a dischargeable bullet'for said major bore: a captive bullet for said minor bore; and an explosive igniter also in said minor bore between said captive bullet and said succeeding gun unit.

6. A gun perforator construction, as set forth in claim 5, wherein said captive bullet forms a closure against the transfer of pressure from one gun unit to the next.

7. A gun perforator comprising: a body structure dening cartridge bores, gun bores, detonator bores and connecting passages; said cartridge bores and gun bores being connected in sets to form a plurality of gun units; bullets and explosive cartridges for said gun umts; said passages and detonator bores being interposed between pairs o! said gun units to connect said Igun units in series; said detonator bores being open at opposite ends and communicating with the corresponding' pair of gun units at longitudinally displaced pQints inwardly of its open en'ds; sealing plugs closing the open ends of said detonator bores; and a ring pin and an igniter charge in each detonator bore, the firing pin being disposed between the points of communication between said detonator bore and the associated gun units to form a partition closing communication between said gun units.

8. A gun perforator comprising: a plurality of gun units; means deiining passages serially connecting said gun units; movable partitions in said passages closing communication between said gun units; a shock sensitive igniter in each passage` on one side of said partition mechanically engaged thereby to ignite the gun unit on the corresponding side of said partition when the partition is subjected to explosive pressures originating in the gun unit on the other side of said partition; removable abutments between the gun units for limiting movement of said partitions and affording access to said igniters.

9. A gun perforator comprising: a plurality of gun units; means defining passages connecting vsaid gun units, each of said means incorporating a detonator bore open at its ends and communicating with the corresponding gun unit at longitudinally displaced points inwardly of its open ends: removable scali-ng plugs closing the ends of each detonator bore; a movable partition in each detonator bore between the points of communication of said bore with the corresponding gun units; and a shock sensitive igniter in each detonator bore on one side of said partition and engaged thereby to ignite and initiate discharge of the gun unit on the corresponding side of said partition, when said partition is sub- Jected to explosive pressure originating in the gun unit on the other side of said partition.

10. A gun perforator comprising: a gun body dening a plurality of laterally directed gun bores and an axially directed, inclined cartridge bore intersecting the inner end of each gun bore to form therewith a, gun unit and intersecting the surface of the gun body at a point axially displaced from its gun bore; said gun body defining further a plurality of passages serially connecting said gun units, each passage incorporating a detonator bore; a ilring pin in each detonator bore isolating said gun units from each other; and a shock sensitive igniter on one side of each gun unit adapted to initiate the operation of the gun unit on the corresponding side of said pin when said iiring pin is actuated by pressure originating in the gun unit on the other side of said ring pin.

11. A construction as set forth in claim 10,

wherein the gun units are located in circumferentially displaced planes. said detonator bores extend through said gun body and are openended, and wherein removable sealing plugs close the ends oi' said detonator bores.

12. A construction as set forth in claim 10, wherein the gun unitsare located in circumferentially displaced planes and each detonator bore extends substantially parallel with the cartridge bore oi' one gun unit and intersects the gun bore oi' the adjacent gun unit.

13. A gun periorator comprising: a gun body denning a pluralityof laterally directed sockets and cartridge;l chambers at the inner ends of said sockets; gun ,barrels for said sockets, bullets for said gun barrels and cartridges for said cartridge chambers; said gun body also defining passages connecting said cartridge chambers in series, said passages including a detonator bore; a ring pin in each detonator bore responsive to explosive pressures and separating said gun chambers from each other; and an igniter on one side of each pin adapted to 'initiate operation of the cartridge on the corresponding side of said pin when said pin is actuated by pressure originating in the chamber on the other side of said i-lring pin.

14. A gun perforator comprising: a gun body dening a plurality of laterally directed sockets and cartridge chambers at the inner ends of said sockets; gun barrels for said sockets; said gun body also defining passages serially connecting said cartridge chambers; a movable partition in each passage isolating said cartridge chambers but yieldable to explosive pressure therein; and an igniter on one side of each partiiton adapted to be set oil? by said partition when said partition is subjected to pressure originating on the other side thereof.

15.`A gun perforator comprising: a gun body dening a plurality of laterally directed sockets and cartridge chambers at the limer ends of said sockets; said gun body also defining a laterally disposed detonator bore .between each pair of cartridge chambers and passages extending from axially spaced points of said detonator bore to the adjacent cartridge chambers; a gun barrel for each socket and a cartridge for each chamber; a captive bullet and an igniter in said detonator bore adapted to be set off by said captive bullet to initiate operation of a cartridge in one of said cartridge chambers when said bullet is driven by discharge of a cartridge in the other of said cartridge bores.

16. A gun perforator comprising: a gun body deiining a plurality of laterally directed sockets a-nd cartridge chambers at the inner ends of said sockets; said gun body also defining a laterally disposed detonator bore between each pair of cartridge chambers and passages extending from axially spaced points of said detonator bore to the adjacent cartridge chambers; and a ring pin and igniter in said detonator bore isolating said cartridge chambers and adapted to initiate operation of an explosive cartridge in a succeeding cartridge chamber upon discharge of an exleosive cartridge in a. preceding cartridge cham- 17. A gun perforator comprising: a gun'body defining a plurality of laterally directed sockets and cartridge chambers at the inner ends of said sockets; said gun body also dening a laterally disposed detonator bore between each pair of cartridge bores and passages extending -from axially spaced points of said detonator bore to the adjacent cartridge chambers; gun barrels for said sockets; cartridges for said cartridge chambers; the extremities of said detonator bore intersecti-ng the sides of said gun body; removable plugs sealing the `ends of said detonator bore; and a rlng pin and igniter in said detonator bore isolating said cartridge chambers and adapted to initiate operation of an explosive cartridge in a succeeding cartridge chamber upon discharge of an explosive cartridge in a preceding cartridge chamber.

18. A construction as set forth in claim 17, wherein said sockets and cartridge chambers are displaced circumferentially lfrom each other to de'ne spiral paths along the gun body and each 5 detonator bore is located in a plane common to the cartridge chambers on either side thereof.

ILYD .SPENCERh

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