US2062974A

US2062974A - Well casing perforator

Info

Publication number: US2062974A
Application number: US642410A
Authority: US
Inventors: Wilfred G Lane
Original assignee: TECHNICRAFT ENGINEERING CORP
Current assignee: TECHNICRAFT ENGINEERING Corp
Priority date: 1932-11-12
Filing date: 1932-11-12
Publication date: 1936-12-01
Anticipated expiration: 1953-12-01

Description

Dec. 1, 1936. w. G. LANE A WELL CASING PERFORATOR 2 'Sheets-Sheet l Filed Nov. 12, 1952 Dec. l, 1936. wl G, LANE 2,062,974

WELL CASING PERFORATOR Filed Nov. 12, 1932 2 Sheets-Sheet 2 [46 [3? 3 atented Dec. l, 193

geen ateao'm wam. casino ranroaa'rca Wilfred G. Lane,

Los Angeles, Calif., assigner to The 'ieclinicraft Engineering Corporation, Los

Angeles, Calif., a corporation of California Application November 12, 1932, Serial No. 642,410

12 Claims.

The present invention is an improved casing perforator for oil wells and the like.

It is often desirable to peri'orate a casing, as for instance, where oil bearing sand strata have been drilled thru and cased off and the well extended to greater depth.

When production of the well has become exhausted to a degree rendering its operation unprotable said production can be augmented by perforating the casing to admit therethru oil from sands occurring at other levels.

My invention contemplatesr a gun structure, adapted to be lowered into a well casing on a wire cable, and so constructed that it can be safely and effectively operated and controlled from the mouth of the Well, and whereby a. number of projectiles can be iired, consecutively, either singly or in groups simultaneously, to perforate a surrounding casing and penetrate the formation'behind it.

As oil is usually encountered at great depths, and as the casings in deep wells often contain liquid, certain problems are presented which are not met with in ordinary gun iire practice. Again the diameter of tools capable of being run into v -Well casings is of such small dimension as to limitthe length of the barrel, thru which a projectile is iired,k to a minimum.

Means must be provided to increase the degree of penetration of a projectile discharged from a barrel of such relatively short dimension and the explosive charge `behind said projectile must beprotected against hydrostatic pressure from without. l

Solution of these problems constitutes the primary object of my invention.

Another object is the provision of a gun, of the nature disclosed, which it is impossible to discharge prematurely, or accidentally, when operated in conjunction with conventional well equipment, and one which will be serviceable for repeated use.

Other objects and advantages will become apparent as this description proceeds.

In the accompanying drawings Figure l represents a fragment of well casing shown in vertical central cross section and shows my improved perforating gun as it would appear while being lowered i through said casing.

` Figure 2 is a central vertical cross section of one tubular section of my gun and illustrates the removable connection therewith of an electricallg operated control unit for firing ci explosive charges contained in adjacent sections 55 of the Hgun.

Figure 3 is a fragmentary section of Figure 2, taken on the line III-III.

Figure 4 is a fragmentary section of Figure 2, taken on the line IV-IV.

Figure 5 is a central vertical cross section of a 5 fragment of casing and shows a body of cement4 as having been set around the casing to fill the space between it and the surrounding formation.

'Figure 6 is a view, similar to Figure 5, showing another condition demanding perforation, wherein two concentric strings of tubing are employed, with cement interposed between the two.

Figure 7 is a fragmentary vertical section of the body portion of the gun showing the removable barrel structure and wiring arrangement.

Figure 8 is a diagrammatic view illustrating the wiring and electrical equipment and remote control used in ring my device.

Figure 9 is a detached view of a form of the gun assembly.

Figures 10 and 11 are, respectively, a side elevation, (partly in section) and an end view of a cartridge for containing an explosive charge.

Figures 12 and 13 are, respectively, side and rear end views of a projectile and a retarding element associated therewith.

Figure 14 is a side View (partly in section) of the projectile shown in Figures 12 and 13, as it would appear after having been fired, illustrating the eilect of shearing said retarding element, and

Figure 15 is a vertical cross-sectional view of said retarding element after shearing has been eiected.

Referring to the drawings, the numeral I indicates a wall casing to be perforated. My improved perforating device is lowered into the casing I, as indicated in Figure 1, on a cable 2 unwound from a reel (not shown) at the mouth of the well.

The assembled device is comprised of a maior body portion 3, a hollow cylindrical sleeve member connected thereto, as by threads 6, and a head Threads 8 connect the sleeve 4 to head 1 which 45 is reduced to form a cylindrical extension li integral therewith, thru which extends the cable 2.

The cable 2 serves a dual purpose. It supports the weight of my device as it is run in and out 50 of the casing i and also transmits electrical energy from a source at the mouth of the well to the gun body 3. Said cable is insulated exteriorly as indicated at 2a, Figure 2, and the strands i2 @I which the cable is formed are frayed and emed terial is formed exteriorly to fit the cavity in head 1 and interiorly to t the cast body of babbitt I3. Said bushing is held in place within head 1 by a disc |6 which is held against a seat |1 by a ring I8 threaded at |9 into the open end of head 1.

When so assembled head 1 becomes an integral part or terminal for cable 2, which is securely hel-d in the cylindrical extension II, being embedded in a waterproof compound 2|.

Electrical energy conducted thru cable 2 is transmitted to a button 22, extending thru a hole in the center of insulating disc I6. Said button is urged to contact the cast babbitt body i3 in which the strands I2 of the cable 2 are embedded, by a spring 23. My device is maintained in concentric relation to the casing I by means of spring cages at both ends. Bow springs are attached at one end to head 1 and at the opposite end to a ring 24 slidable on the tubular extension II. Since these springs constantly contact the casing with a firm pressure, they serve the further purpose of.,y providing suitable electrical connection between gun body and casing when the casing is used as the ground or return lead for establishing an'electrical circuit.

The bottom end of body 3 is provided with a similar centering device, a. ring 24a sliding on an extension ||`a of said body.

The body 8'is provided with a yplurality of transverse sockets or recesses to receive separate preloaded electrically. nred gun units to be hereinafter more fully described. These sockets may occur alternately on opposite sides of the body, as shown in Figures 1 and 9. l A means for conducting current to said units for ring the same in,- cludes a. plurality of distributor wires 53, extending through a longitudinal bore |39 in the body, there being a wire provided for each unit. 'I'he end of each wire remote from the unit is connected to a terminal post 54. These terminal posts are mounted in spaced relation around and througha platform 51 of insulative material supported in the space between the body and control unit as clearly shown in Figures 2 and 9.

I will now describe a control unit, interposed between body 3 and head 1, within the sleeve 4, and removable as a unit therefrom, adapted to conduct electrical energy, in successive impulses, for sequential firing of the device.

A cylindrical tube 69, of bakelite or suitable insulative material, is closed at the bottom by a disc 1|, of insulative material, secured, as by screws 12, to said tube. Extending through said disc 1|, in spaced-apart relation are sockets 13 of slipjoint terminals, said members coinciding in number with the terminal posts 54 and positioned to register therewith, so that tube 69 can be inserted and removed from sleeve member 9 and contact established and brokenbetween all of terminal posts 54 and corresponding sockets 13, simultaneously.

Tube 69 isclosedat the end remote from said terminals by a cap 14, secured within said tube, as by screws 16. Secured to said cap by rivets 11 is a U-shaped finger-pull 18, through which slides a pin 19 secured tothe contact button 22.

Electrical energy from cable 2 is conducted through button 22, pin 19 and rivet 11 to a spring contact member 8| depending from the cap 1d.

fAt 82, Fig. 2, within the bottom of tube 89, I show a split ring, preferably of insulative material, adapted to spread when inserted in said tube and frictionally engage the inner wall thereof and, when so engaged, to form a support for a circular platform member 83, and further act as a spacer between said platform member 83 and terminal disc 1| to provide a compartment to receive the electrical control wiring connected to the terminals on disc 1|.

Secured, as by screws 84, to platform 83 is one end of a U shaped bracket member 86, to the opposite end of which is secured as by screws 81, a similar but shorter bracket 88, secured at the top. by screws 89, to a disc 9|, Figs. 2 and 3.

Extending through disc 9| are electrical contacts 92, corresponding in number with contact members 54 in base member 1| of tube 69.

Contacts 92 arc spaced apart and are equidistant from the center of disc 9| to lie in the path of travel of, and be successively energized by, a contact arm 93, secured to a shaft 94 which has its bearing through the center of disc 9|.

Secured to shaft 9d is a ratchet wheel 96. Step-by-step movement of ratchet-wheel 96 is imparted by a solenoid 91, secured to bracket 86 by rivets 98. One end 99 of the magnet coil is connected to spring contact 8| and the other end of said coll -is grounded on the body 3 of the gun.

A spring detent ||3 prevents return movement of ratchet wheel 96.

The step-by-step advance of ratchet wheel 96 moves contact arm 93, successively, into contact with contact members 92 in cap 9|.

To said members 92 are secured as by nuts II 4, ends of wires IIS, the remote ends of which are similarly secured to contact pins I|1 extending through a. terminal board or panel I|8 of insulative material supported on brackets II9 riveted at I2| to bracket 86.

Wires |22 connect the contacts I I1 in the panel 8 with the female members 13 of the slip joint between tube 69 and body 3, said wires passing through centrally disposed apertures |23 in bracket 86 and |24 in platform 83.

Having thus described the means for conducting electrical energy from cable 2 to the distributor wires 53 each of which res a projectile from a gun unit, I will now describe my electrically red gun units.

One of the principal features of novelty in my invention is an e1ectrically-operated remote control utilizing thermal elements instead of percussion or detonating caps, a provision which obviates necessity for mechanica-1 cooking, and makes the tool perfectly safe to operate.

The gun units can be fired only by the closing at the mouth of the well of an electrical circuit which includes said thermal elements. Accidental or premature discharge becomes impossible and means are also provided in said circuit which serve as a tell-tale aifording visual proof when said thermal elements are energized.

Each gun unit comprises a housing or barrel 28a, threaded throughout a portion of its length into asocketof the body 3, and having a portion extending across the bore |39. Suilcient clearance is'provided between the inner portion of the housing or barrel and socket to define a connecting passage for the bore through which wires 53 may pass to other units. A sealing gasket |46 `is interposed between the flanges formed on the housing and in the socket; as clearly shown in Figure 7. Each wire 53 is secured `to a resilient contact finger |4| mounted in the socket and insulated therefrom at |42.

Contact finger |4| is of spring material and presses against the reduced end of a firing contact pin |43 the enlarged head of which extends into a. correspondingly recessed cartridge receiving .explosive chamber |44.

Before the device is lowered in a casing each of the housings 28a is preloaded in the following manner:-

Firingv contact insulated as shown in Fig. 'l |43 is inserted through the cartridge chamber, a cartridge of explosive, of the type shown in Figs. 10 and 11, is inserted in chamber |64, a flanged projectile of the type shown in Figs. 12 and 13 is placed in an inner removable barrel 3| which is screwed into housing 28a.

The preloaded unit is screwed into body 3 compressing the gasket |46 for water seal.

The cartridge consists of a shell Ml closed at each end by wads |48 through which extend contacts |49, connected, one with the other, by a thermal coil |5| adapted when energized to ignite powder or other explosive |52 in said shell. Obviously if shell |41 is of electrically conductive material said shell could serve as ground terminal for said coil. Y l

The projectile consists of a cylindrical body |53 of hard steel conically pointed at one end as indicated at |54 and ilat at the opposite end.

A disc |56 is spot-welded to the ilat end of projectile |53 in` concentric relation thereto. Said disc serves as a gasket seal against water and as a retard in firing, greatly increasing the effectiveness of projectile |53 so far as penetration is concerned.

In the form shown in Figure 9, the body 3 of the gun is made in sections 3a, said sections comprising one or more gun unit assemblies and each section provided with means for detachable engagement with an adjacent section whereby an assembly can be made of any desired length and weight. In very deep wells the load imposed upon cable 2 would be excessive if a long gun barrel were employed. Another advantage of this sectional structure lies in the fact that the units can'be more easily machined. Each unit 3a is reduced and threaded as at |38 at one-end and counterbored and tapped at the opposite end in corresponding manner,

In perforating well casing the projectile must have more than sufficient force to penetrate casing In Figure 5 I show. a body of cement |56 surrounding said casing. Obviously, unless said cement be perforatedlno benet would result from perforating the casing.

In Fig. 6 I show concentric tubing strings and Ia with the cement |56 interposed. This requires even greater penetrative power to perforate.

As a concrete example of the utility of my device to perforate casing in a commercially profitable manner I wish to state that I have red the assembly shown in Fig. l and have caused prointermediate string 8%" outside diameter, A. P. I.

oil well casing, wall thickness .40": outer string 10%" outside diameter A. P. I. oil well casing, wall thickness .45".

Operation My invention is operated preferably from an automotive truck. Perforation service requires, in addition t0 transportation, a source of electrical energy, a reel for the cable 2 and a means for rotating said reel to lower and raise several thousand feet of cable and the weight of the gun.

Assuming this equipment to be positioned near the mouth of a well and that casing Fig. l, is to be perforated, the device is lowered through .the casing to a point where perforation is to be done. Spring cages 25 serve as a centering means and as an electrical contact for grounding the body 3.

Before lowering said body all of gun units 28 have been preloaded, and all of wires 53 have been connected to terminal posts 54 and through control unit 69 to cable 2 in head 1.

Referring to the wiring diagram, Fig. 8, cable 2 is connected at the end remote from the gun body 3 with a source of electrical energy (preferably a direct current generator driven by truck not shown) by positive and negative wires 16| and |62, the positive leading through the reeled cable 2 to the button 22 in the head 'l of the gun, and the negative being grounded to the casing The circuit thus established is broken by a switch |63, and the positive side includes an ammeter A.

If switch |63 be closed, contact 8|, Fig. 2, of the control unit is energized, and current passes thru contact arm 8|, energizing, through a wire |66, solenoid 91, grounded by a wire |66 connected through one slip joint connections 'i3 and 54 with a plate |61 through which extends a screw |68 serving to ground the solenoid 6l and to secure platform 51 to its support and body 3.

When so energized, the coil of magnet 3l moves the core ||l|, actuating elbow lever |63, and moving, through arm |06, the lever |61, causing pawl |69 to advance ratchet wheel 96 and contact arm 93 into engagement with one of contacts 32, current passing therethrough, and through wires ||6 to panel ||8, thence through wires |22, slip joint terminals 56 and 13, and wires 53. The current then passes to the thermal elements in the gun units and is grounded to the body through the sealing and re retarding discs.

This fires the charge in the explosive chamber destroying the thermal coil, and breaking the electrical circuit.

This operation can be repeated to fire successively the remaining charges, by repeated operation of switch |63.

Any number of said charges may be fired, in groups, simultaneously, if desired, by pre-arrangement, by connecting two or more o the terminal contacts on the panel ||8.

Firing contact |43 is insulated throughout its length from housing 28a, as shown at At i12, Fig. 8. I show, interposed between contact nger 8l and arm 93, current limiting resistance for the purpose of preventing the contacts 92 from becoming burned by overload.

5- The function of ammeter A is to provide visual proof` o f the rupturing of each off the thermal elements I5| and consequent tiring of each. ex- -plosive charge thereby. When switch |63 is closed the ammeter indicates the entire amount of current consumed by the device, which total f amount is decreased to the known value consumed by the solenoid 9i alone when that circuit in which the thermal element is connected is open-circuited by the rupture of said element.

When switch E63 is opened, and solenoid 1Si 'thus de-energlzed, a spring H3, Fig. 4, returns arm mi to its initial dotted-line position for repeated operation.

I wish to call particular attention to that phase of my invention illustrated in Figs. 12, 13, 14 and 15. I have found that spot-weld connection of disc ld is a. decided factor in increasing the velocity and hence the penetration of projectile 53. r 4

When the charge behind the disc is fired a portion of said disc, designated at lda, is sheared from the disc by gas pressure, adhering to projectile i53, and is carried away thereby.

This portion, ia, is larger in diameter than the projectile. and said portion exactly .fills said bore and forms as nearly a perfect seal against the dissipation of expansivegases as it is possible to make. The Welded portion lda parts from disc ld and 35 assumes the shape of a cup leather behind a piston, as indicated in Fig. 14. the skirt or trailing edge being exactly coincident with the bore diameter I(B D) and necessarily larger than projectile 553 and therefore a more perfect seal.

m I claim:-

1. Awell casing perforator including a body having a lateral recess therein, a conductor adapted to be connected with a source of electric energy and terminating Within said recess, and a L5 separate preloaded electrically fired gun nit removably positioned in said recess and electrically connected with the conductor by insertion therein.

2. A Well casing perforator' including a body i@ having a lateral recess therein, a conductor adapted to be connected with a source of electric energy and terminating within said recess, a separate preloaded electrically red gun unit Aremovably positioned in said recess, and resil- 5 ient contact means electrically connecting the conductor and gun unit upon insertion of the gun unit in said recess.

3. A well casing perforator including a body having a lateral recess, a contact Within said D recess adapted to be yconnected with a source of electric energy, a separate preloaded electrically fired gun unit comprising a housing removably positioned in said recess having an inner. explosive chamber andl an outer removable barrel ,5 carrying a projectile, and a firing conductor exigvtending through a wall of said housing from the `explosive chamber and engaging the recess contact when the housing is positioned therein.

4. A well casing perforator includinga body havi ing a plurality'of lateral recesses therein, a plu- -raiity of. conductorsl each terminating in a. separate recess, means for sequentially connecting each conductor with a source of electric energy, a separate preloaded electrlcallyred gun unit removably positioned in eachrecess, and contact The bore acts as a forming die' means on each gun unit engaging the conductor terminal in the recess upon positioning therein.

5. An electrically red well `perforator including a body having a plurality of gun units therein, conductors for each unit extending therefrom and terminating each in an individual terminal post at the top of said body, a sequential iire control unit arranged above said body, a plurality of connecting sockets in the bottom thereof each adapted to receive a body carried conductor post upon assembly, and a combined supporting .and conducting cable for the assembly in contact with the iring control unit. 6. An yelectrically fired well perforator including a having a plurality of gun units therein, conductors for each unit terminating adjacent the top of said body, a separate sequential hre control unit above said body, conductors therein terminating adjacent the bottom there.- of, slip joint contacts connecting the gun unit and control unit conductors, a combined supporting and conducting cable having a head in electrical contact with the upper end of the control unit, and a protecting sleeve for the control unit connecting the body with said head.

7. The combination with a gun type perforator including a gun body having laterally directed sockets, a plurality of laterally directed gun units mounted therein, Said sockets being at least in part diametrically larger than said gun units to denne passages therearound, and said body having an axially centered bore connecting said passages; of a wiring arrangement including distributor wires threaded through said bore and passages around the several gun units and branching one at a time to the rear ends of the gun units; 'and contact means assiated with each gun unit and branch of a distributor wire to connect electrically said aun unit therewith.

8. In a gun type Well casing perforator; a. gun body including laterally directed sockets and axially disposed apertures connecting said sockets; gun units tting said sockets and having portions spaced from the walls thereof to define therewith annular passages interposed between said apertures; each of said gun units having a cartridge chamber and an aperture extending from the inner end of the gun unit into said chamber and there enlarged; a contact means including an insulated contact pin iltting said aperture, a contact head tting said enlargement and insulated therefrom, vsaid contact head adapted to seat against the base of said enlargement to seal against pressures within said chamber, the opposite end of said Din projecting beyond the inner end of the gun unit; distributor wires threaded through said apertures andpassages, and a contact element disposed at the base end of each socket and engageable with of said contact pin, there being a wire for each contact element.

9. In a gun type wel] casing perforator; body having an axially directed bore and ally directed sockets intersecting said bore; distributor wires threaded through said bore and positioned contiguously to the walls of said sockets; gun units fitting said sockets and being sufiiciently smaller to clear the wires therein; and contact means connecting said gun units with the respective distributor wires.

10. In a gun type well casing perfcrator; a gun vbody having an axially directed bore and laterally directed sockets intersecting said bore; distributor wires threaded through said bore and SEUR positioned contiguously to the walls of said sockets, each of said sockets being threaded at its outer end and having a sealing flange inwardly of said threaded portion; a gun unit for each socket, each gun unit having a corresponding threaded portionl and a sealing ange, said gun unit beyond said flange being smaller than but conforming to the inner portion of said socket n to define therewith a sealed chamber for accommodating said wires; and contact means connecting said gun units with the respective distributor W1res.

11. In an electrically fired gun type Well casing perforator, a body having an axially directed bore and aplurality of lateral socketsrintersecting said bore, gun units in said sockets each including a barrel extending across said bore and having its periphery defining with thesocket a connecting passage for the bore, and re controlling means utilizing the bore and passages to connect the units to a source of electric energy to permit successive ring of said units.

12. In an electrically fired gun type well casing perforator, a body having an axially directed bore and a plurality of lateral sockets intersecting said bore, gun units in said sockets each including a barrel extending across said bore and having its periphery defining with the socket a connecting passage for the bore, re controlling means utilizing the bore and passages to connect the units to a source of electric energy to permit successive firing of said units, and coacting securing and sealing means incorporating the outer end of each socket and its gun barrel. WILFRED G. LANE.