US2388938A

US2388938A - Firing head for gun perforators

Info

Publication number: US2388938A
Application number: US552165A
Authority: US
Inventors: James G Smylie
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-08-31
Filing date: 1944-08-31
Publication date: 1945-11-13
Anticipated expiration: 1962-11-13

Description

Nov. 13, 1945.

J. G. SMYLIE FIRING HEAD FOR GUN PERFORATORS 2 Sheets- Sheet 1 Filed Aug. 51, 1944 INVENTOR.

'J'AHES 6.5mm E BTTOR/VEY.

NOV. 13, 1945. J s l 2,388,938

FIRING HEAD FOR GUN PERFORATQRS Filed Aug. 31, 1944 2 Sheets-Sheet 2 Patented Nov. 13, 1945 FIRING HEAD FOR GUN PERFORATORS James G. Smylie, Houston, Tex.

Application August 31, 1944, Serial No. 552,165

14 Claims.

The invention relates to a firing head for gun perforators of the type which are lowered into a well bore in order to perforate a well casing.

Considerable difiiculty is encountered with gun perforators due to the fact that they are lowered many thousands of feet into a well bore in the column of liquid in the well and are subjected to the pressure of the static head of such column of liquid. This pressure often affects the firing mechanisms which have been used heretofore andv in some instances has caused the premature firing of the gun, thus damaging the well or the firing mechanism has failed to operate when the proper location has been reached.

It is, therefore, one of the objects of the present invention to provide a firing mechanism which is normally locked against operation until the desired elevation ha been reached and the tool subjected to a predetermined number of revolutions by rotating the operating pipe o which it is connected, all of which operations must be per formed before it is possible to fire the gun.

It is another object of the invention .to provide a safety firing head for gun perforators.

Another object of the invention is to provide a firing head for gun perforators for operation upon rotation of the body relative to an anchor disposed in the well bore.

Still another object of the invention is to provide a combination firing head and fiowpipe for gun perforators so that the flow of fluid entering the well after the perforations are made can pass upwardly through the firing head to the surface.

A still further object of the invention is to provide a firing head for'gun perforators which may remain in the well bore after the perforations are accomplished and serve as a flow pipe for the-fluid from the formation.

Still another object of the invention is to provide a firing head which can be utilized to fire a gun perforator and thereafter manipulated to anchor the firing head in the well as a flow head.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings wherein:

Fig. 1 is a vertical section of the tool in the position in which it is lowered into the well with the firing mechanism locked against operation.

Fig. 2 is a-side elevation of the construction of Fig. 1.

Figs. 3 and 4 are sections taken on the lines 3-3 and 4-4 of Fig. 1 respectively.

Fig. 5 is a vertical sectional view of the tool in the well after having been operated to unlock the firing mechanism and showing the upp r portion of the firing head in such position.

Fig. 6 is a sectional View which is a continuation of Fig. 5 and illustrates the firing-mechanism about to be released. M H

Fig. '7 is a section taken on the line Fig. 5. Fig. 8 is a section taken on the line 8.l8- of Fig.6. 'f j The firing head or tool is made up ofa body 2 which has a nipple 3 threaded at 4 in its lower end. This nipple has a'reces's 5 in which the plug 6 carries a plurality of primers or detonators 8 disposed in position to fire into the con duits or passages 9 whichextend down into the gun perforating mechanism not shown. There are preferably four ,of these detonators, all of which are fired to insure the eXplosion'o-f the gun perforator. I p

The plug 6 is formed with atapered socket or IFW]. u in which the hammers l2 are-arrangedto' seat. These hammers form a circular member having the tapered surfaces 13 thereon to (:0 operate with the bowl II. The lower ends ,of the hammers have a rid e l4 thereonto' strike the detonators 8.

pref

These hammers are normally urged toward detonators by a spring [6 arranged in the recess 5. The hammers, however, are restrained from movement against the detonators by means of the plunger ll engaging the tapered surfaces l8 on the inner lower portion of the hammers .l 2. The spring I6 urges all of the hammers downwardly, but they are limited in this movement by abutk ment against the plunger I! which preferably bears against the plug 6 at the point 20 so-as to insure the locking of the hammers against further downward movement.

This plunger I! is carried by a rod 22 extends through a series of packing or stuffing boxes 23 toinsure that there will be no leakage into the chamber 5 around the detonators 8. .This

rod 22 has a nut 24 adjustably arranged on its upper end and the rod passes through the opening 26 in a plate 21 carried by the rods 23' which pass through the openings 29 in the upper ..p i-f tion of the body 2. A cap 3!) serves to enclose the upper end of the rod 22 injury.

of slots 39 therein which receive the shoes 40 and protect it against The rods 28 are connected to a collar 35 which is mounted in the anti-friction bearings 35 in the body 31 of a cage 38. This cage has a plurality.

on the inside of the cage. These shoes normally bear against the inside of the casing 45 as best seen in the top of Fig. 5.

The inside of this body 31 has the recess 46 therein which carries a split spring ratchet nut 51- having the ratchet threads 48 therein. The two halves of this nut are held together by the springs 49 as best seen in Figs. 1 and 2.

A mandrel 50 is threaded at in the upper end of the body 2 of the firing ,head, lbutiis iboth slidable and rotatable in the body 31 of the firing head and the sleeve 42 thereof. This mandrel has ratchet threads 52 thereon to latch the I ratchet threads 48 in the nut 4-! .so that the-entire cage 38 may move upwardlyrelative to the mandrel, or if the cage is held stationary rthe mandrel will move downwardly with .respect thereto. These threads face in one direction, however. so that rotation of the mandrel will cause axial movement in one direction, but a sharp pull on the 'mandrel in the other direction will cause the threads onthe mandrel to slide throughthe threads onthenut by expanding against 'thetension of'the springs 49 so that .themandrel may be resetmreturned to its orig inal position relative tot'he cage by such a sharp ,pull.

In actual operation-the 'partswill'be assembled as shown in Figs. 1 and 2 and the tool will be lowered into the well bore through the casing 45 to nearly "the "elevation where the perforating is to be accomplished. In fact it will be lowered so that thebtille'ts to 'be discharged areprobztbly somewhat above "the intended perforation. During this lowering operation the "drag shoes '40 .w'ills'lide along the'inside ,of'the casing and when the mandrel is rotated they will tend to hold the cage 38 against rotation. its the rotation proceeds the mandrel 5D andthe body 2 will move downwardly 'as the threads 52 on the mandrel move through the threads 48 in the nut 41 to the position shown in Fig. 5. This relative movement between the *body and'the cage causes an identical relative longitudinal movement between the plate '21 and the body 2 0f the firing head. This movement is sufiicient to cause the plate "to move against the nut to the position shown in Fig. 6 whereupon continued movement of the cage and the fir-ing 'head away from each other causes the *rod 2-2 to move relative to the body 2. This *movement picks up the hammers ['2 due to movement of the plungers l andcauses the hammers tofoe lifted against the :compression of the spring 4% so as to cook thespring and urge the hamme i2 downwardly.

"Il'le hammers are not released, however, until they have been raised suflieierftly to expand laterally and permit the plunger =1"! "to pass upwardly through the taperedarea 1'8 which has become enlarged'as seen in Fig.6.

'Dnlya slight additional movement beyond shown in Fig. *6 will allow the hammers to slide downwardly around the plunger 11 due to the force of .thespring I15 so that'they'willbe snapped against the detonators 8 to effect the firing thereof.

'It seems obvious from this arrangement that there can be no accidental or premature firing of the detonators and the operator can obviously set the tool so that he knows the number of rotaltions of the mandrel 5B which will be required inorder to effect the firingo'f the detonators. In this 'manner the operator knows precisely when the 'firing .is to take place and he knows that the movement of the parts is such that the buillets will perforate the casing at the intended elevation and that the tool is now in position to receive a flow of fluid from the perforations. Such flow will enter the window 60 in the body 2 and may move into the passage 6! which extends upwardly through the mandrel into the operating pipe which may be a tubing, drill stem or production string of pipe. In this manner a. sample of the fluid may be obtained at the surface if desired.

Another feature or combination 'of the firing head is that the rods 64 connected to the sleeve 42 of the cage may have connected thereto any conventional type of slips or slips and packer so rthat the firing head may be anchored in the well and form a seal inside of the casing to compel the :fiow of zfiuid upwardly through the passage 6| in themandrel.

The slips may be of a suitable type which can he set by raising up on the mandrel 50 and then setting down the weight of the pipe thereon .and the packer may be similarly set as .is well understood'in the art. The anchoring device has not been shown because they may be any conventional equipment, but the invention contemplates the combination of such slips and packer with the firing "head so as .to permit the firing of the gun perforator, the sampling of the fluid, or the permanent location :of the tool in the well for flowing or pumping'purposes.

What is claimed is:

1. A'firingmechanism for gun perforators comprising -a body, a detonator cap therein aIhammer to strike said cap, spring means to be cocked to snap said hammer, means to retractsaidhamm'eragainst said spring including arod movable axially to lift said hammer axially, and .means movable relative to said body upon rotation .of said body relative thereto to release saidrod.

'2. Airing mechanism for gun perlorators comprising a body, a detonator cap therein, .ahammer to strike said cap, springmeans to be cooked to snap said hammer, means toretraotsaid hamer against said spring including a .nod movable axially to lift said hammer axially, and means movable relative to said body upon rotation of said body relative thereto, and additional means to release said hammer after a predetermined movement thereof.

3. A firing head for gun .perforators including a body, a cage slidably connected thereto, a .mandrelfixed to said body and extending through said cage, a threaded connection between said cage and mandrelso that rotation of the mandrel and body relative to the cage eifects sliding movement of the cage, .and firing means to .be cocked and released by such movement.

'4. A firing head for gun perforators including a body, a cage slidably connected thereto, .a mandrel fixed to said body .and extending throughsaid cage, .a. threaded connection between said cage and mandrel so that rotation of the mandrel andbody relative to the cage effects sliding movement of the cage, and firing means to be cocked and released by such movement, and additional means on the cage to drag on the well casing to hold the cage against rotation.

5. A firing head for gun perforators including a body, a cage slidably connected thereto, a mandrel fixed to said body and extending through said cage, a threaded connection between said cage and .mandrel so that rotation of the mandrel and body relative to the cage .eifects sliding movement of the cage, and firing means to be cooked and released by such movement, said threaded.

connection including a split spr'ingnut andratchet thread so as to allow return of said mandrel.

6. A firing head for gun perforators including a body, a cage slidably connected thereto, a man drel fixed to said body and extending through said cage, a threaded connection between said cage and mandrel so that rotation of the mandrel and body relative to the cage efiects sliding move ment of the cage, and firing means to be cocked and released by such movement, said threaded connection including a split spring nut and ratchet thread so as to allow return of said mandrel to set slips or a packer in the well.

7. A firing head for gun perforators including a body, a cage slidably connected thereto, a mandrel fixed to said body and extending through said cage, a threaded connection between said cage and mandrel so that rotation of the mandrel and body relative to the cage effects sliding movement of the cage, and firing means to be cocked and released by such movement, said mandrel being hollow so as to permit a flow of fluid therethrough which results from the perforation.

8. A firing head for gun perforators including a body, a cage slidably connected thereto, a mandrel fixed to said body and extending through said cage, a threaded connection between said cage and mandrel so that rotation of the mandrel and body relative to the cage efiects sliding movement of the cage, and firing means to be cocked and released by such movement, said firing means including a pull rod, firing hammer to be retracted thereby and a spring to be compressed by the retracting hammer.

9. A firing head for gun perforators including a body, a cage slidably connected thereto, a mandrel fixed to said body and extending through said cage, a threaded connection between said cage and mandrel so thatrotation of the mandrel and body relative to the cage effects sliding movement ofthe cage, and firing means to be cocked and released by such movement, said firing means including a pull rod, firing hammer to be retracted thereby and a spring to be compressed by the retracting hammer, and a tapered face on which said hammer slides so as to release for firing after a predetermined movement.

10. A combination firing and flowing head for wells comprising a body, a cage, means to effect relative longitudinal movement of said head and cage to effect firing of a gun perforator, an operating mandrel connected to said body and having a flow passage therethrough to'allow flowing of the well after firing of the head.

11. A combination firing and flowing head for wellscomprising a body, a cage, means to effect relative longitudinal movement of said head and cage to efiect firing of a gun perforator, an operating mandrel connected to said body and having a flow passage therethrough to allow flowing of the well after firing of the head, said cage being adapted for connection to slips and a packer to direct the flow through said mandrel.

12. The combination firing and flowing tool for wells including an operating pipe having a hollow mandrel thereon and a gun perforator firing head body having a passage therein and connected to the mandrel, a cage on the body movable to effect firing of the gun perforator so that fluid may flow through said mandrel and 13. The combination firing and flowing tool for wells including an operating pipe having a hollow mandrel thereon and a gun perforator firing head body having a passage therein and connected to the mandrel, a cage on the body movable to efiect firing of the gun perforator by rotation of the pipe and body relative thereto so that fluid may flow through said mandrel and pipe.

14. The combination firing and flowing tool for wells including an operating pipe having a hollow mandrel thereon and a gun perforator firing head body having a passage therein and connected to the mandrel, a cage on the body movable to effect firing of the gun perforator so that fluid may flow through said mandrel and pipe, and means to anchor and seal said tool in the well bore by manipulation of said pipe and cage after firing.

JAMES G. SMYLIE.