US2169671A - Casing perforator - Google Patents

Description

Aug. 15, 1939. R. D. WALKER 2 cAsING PERFoRATcR Orginal'Filed June 22, 197256 2 Sheets-Sheet 1 Mue vvwy EIS 15, 1939. R. D. WALKER 2,169,671

CAS I NG PERFORATOR Original Filed June 22, 1936 2 Sheets-Sheet 2 Cal Patented Aug; 15, 1939 UNITED STATES PATENT OFFICE CASING PERFORATOR Robert D. Walker, Dallas, Tex., asslgnor of onehali to Vera, E. Tex.

Yarbrough, Harris County,

Apmiamlm June 22, 193s, serial No. '86,618 Y r ,Renewed .my zr, 193s 15 Claims.

in. which eliminates running the perforator into said casing on aY cable, or by other means, and also permits the well to ilow` immediately` after the casing is perforated, without the necessity of removing the perforator from the well casing.

Another object of the invention is to provide an improved device for perforating well casing which is arranged to be located in the well casing permanently, said device having means for perforating any desired portion of the casing so that any desired amount .ofV producing sand may be exposed, whereby the proper oil and gasV ratio of the production may be established.

Another obect of the invention is to provide an improved device for perforating a well casing which includes a plurality of cartridges arranged to be fired independently'of each other, whereby each cartridge may be red at any desired time. A further object of the invention is to provide an improved casing perforator which is permanently located in the well casing, and including a plurality of cartridges with means for adjusting the ring means for the cartridges, whereby after the device is lowered-into the casing the cartridges may be i-lred in any desired predetermined order, which perniits casing oi the entire producing sand strata, which eliminates the guesswork in setting the casing a proper distance above the rathole.

Still another object of the invention is to provide an improved easingperforator which properly perforates the casing without removing the device from the casing and which in the majority of cases also eliminates swabbing of the .which an example of the invention is shown, and

wherein:

Figure 1 is a view, partly in elevation and partly (Cl. 16d-0.5)

ln section, and showing a casing perforator, constructed in accordance with the invention, within a well casing,

Figure 2 is an enlarged vertical, sectional view of the perforator, A r

'Flgure isan enlarged vertical, sectional view of the contact housing.

Figure 4 is an enlarged, vertical, sectional view of one of the cartridge housings,

Figure 5 isa horizontal, cross-sectional view, A

taken on the line 5-5 of Figure 2,

taken on the line 8 6 of Figure 2, and

Figure 'l is a wiring diagram of the ring means for the cartridges.

In the drawings, the numeral I designates the usual casing of an oil well, which casing is cemented in the bottom of the hole A. The tubing I I extends downwardly through the length of casing in the usual manner. It has. been the usual practice to set the lower end of thev well casing a proper distance above the rathole of the well so as to expose the proper portion of the producing sand. It is the portion of producing strata which is exposed which controls the gas and oil ratio of the production, and therefore, if the casing is set toohigh, a high gas to oil ratio is had whereby the total oil possible is notI produced; if the casing is set too low, then the lifting power of the gas is not completely utilized, thereby necessitating the earlier use of pumps. The proper setting of the casing to obtain the proper gas and oil ratio is more or less guesswork on the part of the operator, and in the majority of cases, said casing is improperly set.

Inperforating the casing after the same has been set', it is possible to case the entire producing sand or area by setting the casing on bottom. Then by perforating said casing at desired points along said producing area the proper oilgas ratio of the production may be had.

In carrying out the invention, an elongate housing B is threaded onto the lower end of the tubing I I, whereby it may be lowered into the casing with the tubing. The housing comprises a plurality of superimposed cartridge collars I (Figure 4) which are connected to each other by suitable screw threads. The uppermost collar` has the lower end of a sleeve I6 connected thereto and the upper end of this sleeve is threaded into the lower end of the tubing II. The lower 'end of the housing B, formed by theY collars and sleeve, is closed by a plug I'I which is threaded into the lowermost collar, while the upper end of the housing is closed by a transverse plate Figure 6 is a horizontal, cross-sectional view,V

I8 extending across the upper end of .the sleeve I6 and preferably made integral therewith.

'I'he upper end of each collar I5 is provided with an externally threaded nipple I9, and the lower end is formed with an internally threaded socket 20. With this arrangement, it will be seen that a flush joint is provided when the collars are connected together. If desired, the collars may be provided with registering key slots I3 in their outer surface which slots receive keys I4 to lock the collars in their connected position.

Each collar contains a cartridgefZI which extends diametrically across the same, and each cartridge includes a cylindrical shell 22 Which has one end threaded into an opening 23 in the wall of the collar. The opposite end of the shell is rounded, as shown in Figure 4, and terminates short of the opposite wall of the collar. This rounded end of the shell is held in position by `a plug 24 which is screwed into an opening 25 in the wall of the collar. The inner end of the plug is recessed to snugly engage the rounded end of the shell and firmly hold the same in its horizontal position within the collar.

The shell of each cartridge has gun powder, or other explosive material 26 packed in its inner end and a slug 21 is located within the shell forwardly of the powder. It is noted that the slug is mounted approximately midway Within the shell, whereby the empty portion of said shell forwardly of the slug forms a barrel for directing the slug when the powder is fired. The outer or open end of the shell is closed by a disk 28', which is preferably made of a thin metal, or other light material. The purpose of the disk is to close the shell and prevent the well fluids from entering the same before the cartridge is fired. The light material of which the disk is constructed does not, however, interfere with the exit of the slug when the powder is exploded.

For exploding the powder to eject the slug 21, a pair of electrical contacts 28 and 29 are mounted diametrically opposite each other in the wall of the shell. The' contacts are suitably insulated from the shell and are located in that portion of said shell which contains the powder 26, whereby the inner end of the contacts are in said powder. 'Ihe contacts have their inner ends connected by a fusible wire 30, and electrical wires 28a and 29a connected to a source of suitable electrical supply lead irom the contacts.

W'hen electrical current is directed through the wires 28a and 29a, it will be seen that the current flows through the wire 30, fusing the same and causing a spark. This spark ignites the powder 26 which explodes, directing its force, against the slug 21. This force ejects the slug from the end of the shell, or barrel, and due to the disposition of the cartridge, the slug is directed through the well casing I0, thereby perforating the same. It is noted that the cartridge of each collar is located out of radial alignment with the next adjacent cartridge, whereby each cartridge directs its slug into the well'casing at a different radial point than the others (Figure 5).

Any desired number of cartridge collars I5 may be employed, and by ring said cartridges in a desired order, it will be seen that any portion of the casing may be perforated and therefore, any section of the producing area, exposed, whereby the proper oil-gas ratio of the production may be had. The cartridges are connected to and carried by the lower end of the tubing and are lowered into the casing therewith. After the desired number of cartridges have been iired, the

production-immediately starts, as the well iluids enter the casing and then the tubing through openings II' in said tubing. The uniired cartridges remain in the well and may be fired at a later time.

With this arrangement, it is not necessary to lower the perforating device on a cable, or other lowering tool, fire the cartridges, then remove the tool and then insert the well tubing. The device is lowered once and remains until the tubing is removed. If one or two cartridges are red and the proper gas-oil ratio is not obtained, itis only necessary to lire additional cartridges until it is obtained. 'Ihis results in a great saving of time and labor.

Any suitable means may be employed for conducting the electrical current to the cartridges and for ring said cartridges in any desired order. However, it is preferable to employ a means such as is shown in the drawings. This means in-I cludes an elongate vertical shank 3| which extends upwardly from the plate I8 which closes the upper end of the housing B, being preferably threaded thereinto. The shank is made of hard rubber, or other electrical insulating material and is formed with an axial bore 3| which terminates near its upper end. A trio of annular heads 32, 33 and 34 are spaced vertically on the shank being integral therewith. -Each head has a rounded top while its underside is at forming an annular shoulder, and ilat electrical contact rings 32', 33' and 34 are secured to these annular shoulders.

For conducting electrical current to the annular rings, an annular body 35, made of a suitable insulating material and having its lower end open is adapted to be lowered over the heads, is shown in Figure 2 The head is provided with a trio of electrical contact rings 36, 31 and 38 located within the body. Each ring has inwardly curved flexible spring fingers extending therefrom and when the body is positioned over the heads, the flngers of each ring engage one of the contact rings of the heads, whereby electrical connection is made between the rings 32', 33 and34' and the rings 36, 31 and 38 respectively. The body 35 may be lowered over the heads by a cable 39, or other means, and due to the rounded heads, it is obvious that the curved fingers vwill readily pass thereover and engage the rings on said heads. rI'he body isordinarily lowered within the tubing after the housing B has been positioned Within the casing, although it could be positioned before said housing is lowered. The body may be removed at any time by merely pulling the same upwardly, and the inherent resiliency of the fingers permit them to be bent so as to disengage the heads.

For controlling the current to the rings of the lbody 35, a double throw knife switch 40 is provided. This switch is located at the top of the well and includes four contacts 4I, 42, 43 and 44, the former two ycompleting one electrical circuit while the latter two close another circuit. One side of the blade 45 of the knife switch is electrically connected by a wire 45a with one si'de of the electrical supply, while the other side of said blade is connected by a wire 45h with the other side of said supply, whereby the current Hows through the blade.

Assuming the blade 45 to be in engagement with the contacts and 42, the electrical current flows from the contact 4I, through a wire 4Ia which has its other'end connected to the ring 36. From the ring the current `flows to the ring 32', andthen through the wire 28a which leads to the contact 28 of the cartridge 2l. From the contact 23 the current passes to the contact 29, then through the wire 23a to a contact 46 which is located within an insulated case 41 (Figure 2). The case is mounted within the upper end of the housing B and depends axially from the plate i8, being threaded into a collar I8 formed on the underside of said plate. An electric motor 46 is mounted within the case and the motor shaft extends axially therethrough. The shaft has a plurality of metallic disks 49 mounted thereon and one of these disks is provided for each cartridge. That is, the uppermost disk controls the uppermost cartridge, and -so on. The uppermost disk has a. contact 49 adapted to engage the contact 46 which is connected with the uppermost cartridge by the wire When the contacts 43' and 46 are engaged the current flows through the disk and to one side of the motor 48, from which it passes through a wire 48a. to the contact ring 33' of the intermediate head 33. From the ring 33', the current ilows to the ring 31 and then nally, through a wire 42a. which leads to the contact 42 of the switch 40, whereby the electrical cir- 'cuit is completed. Thus, it is obvious that when the contact 49' of the uppermost disk is engaging the contact 46 on the inner wall of the'case 41, and the switch blade 45 is thrown to engage the contacts 4l and 42, the uppermost cartridge is fired.

At the same time that the wire 30 is fused to re the cartridge, the electric motor is energized momentarily which causes the motor shaft to rotate a predetermined number of degrees. The actual number of degrees which the motor shaft rotates is controlled by the particular construction of the motor. A moton having contact disks mounted on its shaft and adapted to be energized momentarily to move the disks a number of degrees, such as is herein described, is manufactured by the Sangamo Electric Company of Springeld, Ill., and may be purchased on the open market.

As the motor shaft is rotated, the contact 49' is moved off of the contact 46 andthe contact of the disk next therebelow moves into engagement with a contact 50 mounted on the inner wall of the case 41. by a wire 29o with the contact 29 of the next cartridge. The other contact 28 of this cartridge is connected by a wire 28h with the contact ring 34' of the lowermost head 34. The ring 34 is, of course, electrically connected with the ring 38, which is, in turn directly connected by a wire 44a to the switch contact 44. The other switch vcon-tact 43 of this circuit is connected by a wire 43a with the contact 42.

After the rstcartridge has been iired, the contact 49' of the uppermost disk 49 disengages the contact 46, and "the contact of the next disk moves into engagement with the contact 50 leading to the next cartridge. The blade 45 of `the switch 40 is then swung to engage the contacts 43 and 44. When this occurs, the current ows from the contact 44, through the wire 44a, rings 38, and 34', vWire 28h, cartridge contacts 28 and 29, wire 29h, contacts 5U, disk 49 and to the motor 48. Then from the motor through wire 48a, rings 33 and 31, wire 42a, contact 42 and nally through the wire 43a to the switch contact 43, whereby the circuity is complete. 4This res the second cartridge and at the same time The contact 50 is connected energizes the motor to disengage the contacts 50 with the contact of its control disk. The rotation of the motor`shaft, upon disengaging the lcontact 60, moves ther next disk into engagement with a contact (not shown) which connects 'to the next cartridge to be tired. This next cartridge would have one side connected to the wire 28a, while its other side lis connected to its contact within the case, and therefore, as the blade 45 of the switch 40is again swung back to engage the contacts 4I and 42, this next cartridge would be red. Y p

Similarly, the fourth cartridge to be iired would have a contact within the case connected thereto, while its other side is connected to the wire 28h, whereby it is fired as the switch blade 45 engages the contacts 43 and 44. Therefore, the cartridges, in the order of their firing, are connected alternately to the wires 28a. and 28h. As one cartridge is fired, the next cartridge is made ready because its control disk moves into engagement with the contact, located in the case 41, which. is connected therewith. Then as the switch is thrown from one set of switch contacts 4I and 42 to the other set of contacts 43 and 44, the cartridges are fired.

The uppermost cartridge need not be fired first for it is obvious that by adjusting the disks 49 with relation to the contacts within the case, the cartridges may be fired in any desired order. It may be possible to fire two of the cartridges and obtain the proper gas-oil ratio of production. In such cases, the remaining cartridges remain unred. It may occur that after some time, it is desirable to perforate more of the casing, and then it is only necessary to swing the switch blade of the switch 40 and nre one or more additional shots. Once the device has been lowered into the well on the lower end of the tubing il, it remains therein and need never be removed. It does not, in any way, interfere with the well flow. Although only two cartridges have beenshown and described in detail, any desired number may be employed. It is noted that any suitable switch means may be employed in place of the disks, and also the particular means of conducting the current to the cartridge may be varied. It would be possible to connect each cartridge individually to the current supply and provide a switch for controlling the ring of the same.

It is noted that the threads of the cartridge collars are screwed up tight so as to prevent well fluid entering the housing. Also, the heads 32, 33 and 34 on the shank 3l, as well as the casling 35 may be submerged in heavy grease, or

other similar substance, whereby salt water cannot enter the housing to contact the electrical connections` What I claim and desire to secure by Letters Patent is:

1. A device for perforating well casing including, a housing adapted to-be connected to a well tubing and loweredtherewith into said casing, said tubing having a fluid inlet above the housing, a plurality of explosive charges mounted within the-housing, means adapt-ed to be lowered through the tubing and arranged to be detachably connected with the housing for ring each charge individually, the. detachability of said means permitting its removal thro-ugh the tubing after said charge is iired, whereby said means will not interfere with the flow through the tubing,` andl means for directing thel force of each charge against the well casing to perforate the same.

2. A device for perforating well casing including, a housing adapted to be connected to a well tubing and lowered therewith into said casing, said tubing having a fluid inlet above the housing, a plurality of explosive charges mounted within the housing, mea ns adapted to be lowered through thetubing and arranged to be detachably connected with the housing for firing each charge individually, the detachability of said means permitting its removal through the tubing after said charge is-iired, whereby said means will not interfere with the iiow through the tub- 1- ing, means for directing the force of each charge against the well casing to perforate the same, and means for selectively iirig the charges in any desired predetermined order.

3. A device for perforating well casing including, a housing adapted to be connected to a well tubing and lowered therewith into said casing, said tubing having a uid inlet above the housing, an explosive charge mounted transversely within the housing and adapted to be red electrically, means within the housing for conducting electrical current to the charge and terminating in an electrical contact at the upper end of the housing, means adapted to be lowered through the tubing and arranged to bedetachably attached to the housing and engaging the contact for conducting electrical current thereto whereby the charge may be fired, and means for directing the force of the charge against the casing to perforate the same.

4. A device for perforating well casing including, a housing adapted to be connected to a Well tubing and lowered therewith into said casing, said tubing having a iiuid inlet above the housing, a plurality of explosive chargesY mounted within the housing and adapted to be red electrically, a plurality of contacts on the housing, each contact having electrical connection with one of the charges, means adapted to be lowered through the tubing and arranged to be detachably connected to the housing and having electrical connection with said contacts for ring said charges, and means for directing the force of said charges against the casing to perforate the same.

5. A device for perforating well casing including, a housing adapted to be connected to a well tubing and lowered therewith into said casing, said tubing having a fluid inlet above the housing, a plurality ofV explosive charges mounted within the housing and adapted to be fired electrically, a plurality of contacts on the housing, each contact having electrical connection with one of the charges, means adapted to be lowered through the tubing and arranged to be detachably connected to the housing and having electrical connection with said contacts for firing said charges, means for directing the .force of said charges against the casing to perforate the same, and means for selectively nring the charges in any desired predetermined order. f

6. A device for perforating a well casing including, a tubing string adapted to be lowered into the well casing and having means in its lower portion for establishing communication between the interior of the well tubing and the casing, a housing secured -to the tubing below said means, whereby said housing does not interfere with the ow upwardly through the tubing, an explosive charge mounted within the housing and arranged to be red. by electrical current, said charge being positioned to perforate the casing when fired, and means adapted to be lowered through the tubing into contact with the housing for conducting current to the tiring means, said means being located substantially out of the path of the ilow through the tubing when in engagement with the housing.

7. A device for perforating a well casing including, a tubing string adapted to be lowered into the well casing and having means in its lower portion for establishing communication between the interior of the well tubing and the casing, a housing secured to the tubing below said means, whereby said housing does not interiere with the flow upwardly through the tubing, an explosive charge mounted within the housing and arranged to be iired by electrical current, said charge being positioned to peri'orate the casing when fired, electrical conducting means carried by the housing and connected to said charge, and means adapted to be lowered through the well tubing into contact with the conducting means for carrying current to the charge to fire the same and perforate the casing.

8. A device for perforating a well casing including, a tubing string adapted to be lowered into the well casing and having means in its lower portion for establishing communication between the interior of the well tubing and the casing, a housing secured to the tubing below said means, whereby said housing does not interfere with the ow upwardly through the tubing, an explosive charge mounted within the housing and arranged to be red by electrical current, said charge being 'positioned to periorate the casing when fired, electrical conducting means carried by the housing and connected to said charge,. and meansadapted to be lowered through the well tubing into contact with the conducting means for carrying current to the charge to fire the same and perforate the casing, said last named means being readily removable from the tubing so that after the charge has been iired, it may be removed from the tubing to permit an unrestricted ilow through the tubing.

9. A device for perforating a Well casing including, a tubing string adapted to be lowered into the well casing andhaving a well fluid inlet in its lower portion for establishing communication between the casing and tubing, a housing secured to the lower end of the tubing below said inlet, a plurality of explosive charges mounted within the housing and positioned so as to exert their force against the well casing to perforate the same when said charges are fired, electrically operated means within the housing for firing said charges in a predetermined order, and means adapted to be lowered through the Well tubing into contact with the housing for conducting electrical current to the electrically operated means, and means at the surface of the well for controlling said electrically -operated means to lire the charges and perforate the well casing.

` 10. A device for perforating a well casing including, a tubing string adapted to be lowered into the well casing and having a well iluid inlet in its lower portion for establishing communicaltion between the casing and tubing, a housing secured to the lower end of the tubing below said inlet, a plurality of* explosive charges mounted within the housing and positioned so as to exert their force against the Well casing to perforate the same when said charges are red, electrically operated means within the housing for iiring said charges in aypredetermined order, and a contact 13. A device for perforating a well casing iny head adapted to be lowered through the tubing and arranged to be electrically connected to the electrically operated means to conduct electrical current thereto, whereby .the charges may be fired to perforate the casing, said head being removable from the tubing so that after the charges have `been red the head may be removed to permit an unrestricted iiow through the tubing.

1l. A device for perforating a`well casing including, a tubing string adapted to be lowered into the well casing and having perforations in its lower portion for establishing communication between the interior of the casing and tubing, a housing adapted to'be connected to the tubing below said perforations, an explosive charge mounted within said housing and arranged to be iired by electrical current to perforate the well casing, and means adapted to be lowered through the tubing for conducting electrical current to the housing to re the charge and removable after the charge has been red, whereby uid may ow from the casing into the tubing and to the surface without removing the housing from the tubing and without pulling the tubing.

12. A device for perforating well casing including, a housing adapted to be connected in a well tubing and lowered therewith into the casing, said tubing having an inlet above the housing to establish communication between the casing and tubing, a cartridge mounted laterally within the housing and directed toward the casing whereby when red it perforates the casing, said cartridge being arranged to be fired electrically, means adapted to beiowered through the well tubing on a cable into contact with the housing for conducting electrical current to the cartridge within the housing, whereby said cartridge may be nred, the last named means being removable from the tubing after the cartridge has been red, whereby an unrestricted iiow upwardly through the tubing is permitted.

cluding, a tubing having a uuid inlet, a housing secured to the tubing below the inlet. the housing comprising a plurality of collars connected together, an explosive charge mounted in each collar and directed toward the well casing so as to perforate said casing when ilred, electrically operated means within the housing for iring said charges, and means adapted to be lowered through the well tubing into contact with the housing for conducting electrical current to the firing means.

14. A device for perforating a well casing including, a. tubing having a fluid inlet, a housing secured to the tubing below the inlet, the housing comprising a plurality of collars connected to gether, an explosive charge mounted in each collar and directed toward the well casing so as to perforate said casing when red, electrically cperated means within the housing for ring said charges, means adapted to be lowered through the well tubing into contact with the housing for conducting electrical current to the ring means.

and means for selectively iiring the charges in.

any predetermined order.

15. A device for perforating well casing including a housing adapted to be connected to a well tubing and lowered therewith into said casing, said tubing having a iluid inlet' above the housing, an explosive charge mounted within the housing, means adapted to be passed through thel tubing and arranged to be detachably connected with the housing for iiring said charge. the detachability of said means permitting its removal through the tubing after said charge is red, whereby said means will not interfere with the ow through the tubing, and means for directing the force of said ycharge against 'the well casing to perforate the same.

ROBERT D. WALKER.

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