US2140813A - Well casing perforator - Google Patents

Description

F, R. RUTHER @ET AL WELL CASING PERORAIIOR 2A Sheets-Sheet 1 Filed Feb. 25, 1938 All?.

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F. RRUTHER ETAL WELL CASING PERFORATOR 2 Sheets-Sheet 2 Filed Feb. 25, 1938 vNvENToRs Frank P Pu'her lRalph Ll @Wwf ATTORNEY M. Ridi@ Patented Bec. 20, 1938 man Frank R. Ruther and Ralph M. Ridley, Whittier, Calif.

Application February 25, 1938, Serial No. 192,532`

15 Claims.

This invention relates to mechanism for perforating the casing in a well bore, and more particularly to a perforating gun which discharges projectiles by detonating a charge of explosive with sucient force to pass through the casing and into the formation outside thereof.

It is common practice incident to placing oil wells on production, to perforate the Well casing in the productive zone. This is frequently done by lowering some form of mechanical perforating device into the casing to the place where the perforations are desired, and then manipulating the machine from the surface of the ground to perform the perforating operation. Due to the necessity of remotely controlling such devices, satisfactory operation is difcult. For this reason, and also because to more effectively start production, it is desirable to break up the formation surrounding the casing, perforating guns which are readily controllable from the surface of the ground and which nre a bullet or projectile through the wall of the casing and into the formation, have been suggested.

Such guns have usually been characterized by an electrical ring mechanism, and one or more bores for directing the projectiles through the casing.- These perforating guns have also been lacking in flexibility, that is, they were capable of making a denite number of perforations only, 30 and if more were required, the gun had to be removed from the well and another one inserted. It is a principal object of this invention to provide a perforating gun which covers a zone of considerable depth, and which comprises sections which may be successively lowered into the well and fired as conditions dictate, Without the necessity oi any withdrawals.

Another object of this invention is the provision of a perforating gun in winch the explosive 40 discharging the projectile is detonated by a firing pin, operating by impact on the gun.

It is another object of this invention to provide a multi-section perforating gun, in which the successive sections are adapted to slide downprovision of means, whereby a perforating gun of one size may be used to perforate various size casings.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the act companying drawings, which form part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood' that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best dened by the appended claims.

Referring to the drawingsz' Figure 1 is a longitudinal section taken along a. plane passing through the axis of one form of gun;

Figs. 2 and 3 are sections taken along correspondingly numbered planes of Fig. 1;

Fig. 4 is a diagram, showing the periorator in use in a well;

Fig. 5 is a view similar to Fig. 1, but of a modied form of the invention;

Fig. 6 is a cross-section as seen on plane 6 6 of Fig. 5; y

Fig. 7 is a section similar to Fig. 6, but of another modification of the invention;

Fig. 8 is a longitudinal section of an adaptor sleeve;

Fig. 9 is a plan view of the adaptor sleeve; and

Figs. 10 and 11 are details of the projectile.

Referring to Figs. 1, 2 and 3, a form of perforating gun is shownv therein having a cylindrical body I5 providedwith a pair of oppositely directed barrels I6 and I'I, oblique to the vertical axis of the body.' The ends of the body are provided with detachable caps I8 and I9 which serve to confine cartridges 20 and 2l in the barrels I6 and I1 respectively. Each cap carries iii-ing mechanism, indicated by 22, which is adapted to discharge the associated cartridge upon receiving a blow directed generally in axial direction with respect to the body. An opening or passage 23 is provided in the body to accommodate a cable or sand line 2li which serves to guide the apparatus when it is being placed in the well casing, and also to remove it when desired. The entire gun is enclosed in a iluid tight casing 25 of light sheet metal, which serves to exclude air and water from the cartridges and the ring apparatus until such time as the gun is discharged.

In Figure 4, the well casing 28 is to be perforated, and a perforating gun 21 ls shown suspended' in the casing at the place where the lowermost perforations are wanted by means of the cable 24 which may conveniently be the usual sand line of a drilling outfit. The cable has a member 28 secured to it for supporting the gun 21, and suitable weights 29 may be also attached to the cable if desirable, to assist in lowering it into the well.

The perforating gun may be placed on support 28 and lowered into the well along with the cable 24 to the desired level, in position to be later discharged. Or the cable and supportl may be positioned in the well first, after which the gun is placed on the cable and allowed to follow it down- Wardly until it reaches member 28. Due to the well liquid which is always present, the gun will not fall with excessive speed, but will, nevertheless, strike member 28 with enough force to distort the casing 25 and operate the firing mecha.- nism 22 at the lower end.

An additional gun, such as 30, may then be placed on the sand line and allowed to ride into the well. When this gun strikes the gun 21, the ring mechanism in its lower end, as well as that in the upper end of gun 21, will be actuated to iire their associated cartridges. In case the gun 21 has been lowered with the sand line, the impact of the succeeding gun 30 will also cause the lower cartridge in gun 21 to be red. Additolnal guns may be placed on the sand line and allowed to fall in the well, operating the firing mechanism in contacting ends in the same way until a desired length of casing has been perforated, or until the well production indicates a. suicient amount of perforating. After this, all of the guns can be removed together from the well with the same sand line. From the foregoing it will be apparent that there is great flexibility of operation, since the extent of the perforating desired can be determined as the work progresses. Further, it is not necessary to remove the cable or any of the guns from the well until the work is completed.

Reverting to the details of construction, each of the barrels i6 and i1 which are pressed into the body I 5 has a bore 33 which may be suitably rifled. The cartridges 2!! and 2i may be of any type usually employed for this class of work, but are provided with a novel type of projectile 34, as shown in Figs. l0 and 11, having a relatively sharp advancing point 35. For better penetrative ability, this point is placed preferably at or near the edge of the projectile or bullet 34. The adjacent sloping surfaces 3| that define the point, may intersect along the line 32.

Caps i8, i9 are secured to the body by a tapered thread 36 and engage the frusto-conical ends 43 of the body, serving asbreech blocks to hold the cartridges in position. They may be easily removed and replaced, permitting the insertion of new cartridges. The ring mechansms 22 each include a tiring pin 31 slidable in the cap, and a rectangular tiring block 38 having a convex outer surface. The firing block 38 is accommodated in a rectangular recess in the cap and is urged outwardly by a pair of ilat springs 39, screw 40 serving to limit outward movement of block 38. It will be apparent that a blow on block 38 will drive the block inwardly, causing pin 31 to explode the cartridge. Inlorder that the gun may be caused to closely follow cable Ztl as it drops in the well, a closure 4i is provided for recess 23. It may be conveniently secured to the body by screws 52.

aimais It will be noted that casing 25 follows the conguration of the body as far as this recess is concerned, whereby all openings in the casing are eliminated, and at the same time the gun may be readily placed on the cable. lt is to be understood that this casing is of suiiciently light material to be readily distorted by the impact of the falling gun so that the ring mechanism will operate. Further, it will easily rupture when the cartridge is discharged, so as not to impede the gases formed thereby, or the passage of the projectile.

For the most eiective operation of the gun, the place where the projectile leaves the bore of the barrel should be fairly close to the wall of the casing. Obviously this can be readily accomplished by having a gun with a body of suitable diameter for each size casing. However, by the use of an adaptor, as shown in Figs. 8 and 9, a

'small size gun may be eiectively used in large sized casing. By providing a variety of adaptors having diierent external diameters but common internal diameters, a small diameter gun may-be used in a number of larger casings. This is a decided advantage, since the adaptors are simple and inexpensive. The adaptor is used to form an extension barrel.

The adaptor may take the form of a ring t5, divided in halves d6 and t1 along an axial plane.

-The inside of the ring ts closely around the casing 25 of the gun, the outside diameter of the ring being such as to give proper clearance between the adaptor and well casing t8. Each halt` of the ring is provided with an oblique hole such as 49, which forms a'continuation or extension of the corresponding bore 33. The adaptor ring is assembled around the gun after the latter has been placed on the line 2d, screws 5i! accommodated in tapped holes lill formed in gun body i5 serving to accurately secure the adaptor in position.

It may be desirable to have a gun unit capable of handling more cartridges than the form just described. Figs. 5 and 6 show such a form having three barrels', but this is illustrative only, as there may be more than three. The body 5I is cylindrical as before, and has the pressed in barrels 52, 53 and 513, provided with riiie bores, making a less acute angle with the body axis. Each barrel is adapted to receive a cartridge 63, 64 or 65 which may be of the same type as before and is held in place by a breech block 55, 56 or 51. Each breech block is detachably secured to the body by screws 58, thus 'providing access to the y gun barrel for reloading. The upper breech block 55 provides a vertical guide for a ring pin 59 adapted to re the upper cartridge 63 upon downward'vertical movement of the pin relative thereto. This movement may be imparted to it by head 6G, slidably mounted in, a recess 82 formed in the upper end of the body 5 l. Springs S2 urge the head outwardly, screw 6l serving to limit.: this outward movement; Breech block 55 also has a ring pin 66 sliding supported therein and adapted to re cartridge 661 upon being forced downwardly. Firing pin 66 has .a head 83 with a dat upper surface l which is at substantially a right angle with the axis of the body. When the inclined face of the projectile discharged from cartridge 63 strikes the projecting surface 84, the projectile forces the pin 66 downwardly and fires cartridge 615, after which it passes outwardly to perforate the casing. Breech block 51 has a similar firing pin 61 pressed downwardly by the projectile from cartridge 64 thus ring cartridge 65. Thus the initial impact on head 60 is effective to cause the cartridges to be discharged in succession. As many barrels as desired may be provided, each barrel having ring mechanism operated by the projectile of the preceding barrel. A fluid tight casing 68 encloses the gun, which is arranged to be guided by a cable or sand line 24, all as in the iirst form.

When the perforating gun is of sumciently large diameter it may be formed of two similar halves 10 and 1 I, as shown in Fig. 1. The barrels 12 in part 10 for example, can be arranged as in Fig. 5, being' provided with breech blocks 13. These breech blocks each may be held in place by screws 14 and have firing pins 15, all as before. The arrangement of the bores and breech blocks in the other part 1| is identical; thus when they are assembled, the bores will be inclined in opposite directions. In this form the two parts are to be assembled with the cable 24 in axial space between them, and accordingly each part is in a fluid tight casing 16. The two parts may be conveniently held in assembled relation by screws 18, provided with rubber washers 19, 8B to prevent leakage of the well uid into the casing about them.

What is claimed is:

1. In a Well casing perforator, a cylindrical body member, and means forming a gun bore having a straight axis oblique to the axis of the body.

2. In a well casing perforator, a cylindrical body member, means forming a gun bore having a straight axis oblique to the axis of the body, and means forming a breech block adapted to retain a cartridge in said bore.

3. In a well casing perforator, a cylindrical body member, means forming a gun bore oblique to the axis of the b'ody, means forming a breech block adapted to retain a cartridge in said bore, and firing mechanism associated with the breech block adapted to iire the cartridge, and operable by impact.

4. In a well casing perforator, a cylindrical body member, means forming a plurality of gun bores oblique to the axis of the body, means forming a breech block for each of the bores to retain a cartridge in the associated bore, ring mechanism supported by each breech block, and means to cause successive actuation of the ilring mechanism.

5. In a well casing perforator, a cylindrical body member, means forming a gun bore oblique to the axis of the body, and means whereby the body may be amxed on a cable to slide axially thereon.

6. In a well casing perforator, a cylindrical body member, means forming a gun bore oblique to the axis of the body, a cartridge secured in the bore, impact ring mechanism at the end of the body adapted to discharge the cartridge, and a casing enclosing the body to exclude well uid from the bore and ring m 7. The method of perforating well casing which comprises, positioning on a line at the point to be perforated a perforator including a cartridge adapted to be fired by impact, placing a similar perforator on said line so as to fall in the casing until it engages the preceding perforator, said engagement serving to re a cartridge in at least one of the perforators, and placing successive perforators on the line to repeat the operation until the desired amount of perforation is obtained.

8. An adaptor for use with a well casing perforator of the type which discharges a projectile through a bore to penetrate the casing, said adaptor including means providing an extension for said bore.`

9. An adaptor for use with a well casing perforator of the type having a gun bore through which a projectile is discharged to penetrate the casing, comprising a member adapted to iit the outside of the perforator and to be attached to the perforator, said adaptor fitting closely the inside of the casing and having a bore adapted to form a continuation of the gun bore.

10. In a device of the character described, a body adapted to be inserted in well casing, said body having a bore for firing a projectile, and a fluid tight covering for the entire body.

11. In a device of the character described, a gun perforator adapted to be inserted in well casing, and adapted to accommodate one or more cartridges, and means adapted to be dropped onto the device from the top of the well casing for providing an impact force detonating said cartridges.

12. A cartridge for well perforators, characterized by the provision of a projectile having an acute penetrating point, in the form of a tip occurring adjacent the outer edge of the bullet, and all other parts of the. projectile being below said tip.

13. In a device of the character described, a body member having a pair of inclined parallel gun bores, the open ends being located on opposite sides of the member, and means for accom` modating cartridges in the other ends of the bores.

14. In a device of the character described, a body member having a series of gun bores, the cartridge end of one of a pair of adjacent bores being disposed near the discharge end of the other bore, and a ring device for said cartridge end, and in the path of the projectile passing through said discharge end.

15. A. cartridge for well perforators, characterized by the provision of a projectile that has a penetrating point adjacent the edge of the projectile, and a pair of surfaces sloping transverse to the projectile and deilning the point, said sloping surfaces intersecting along a line sloping from the point to the opposite edge of the projectile.

FRANK R. RUTmR.

H M. RIDLEY.

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