US3176770A - Perforator initiating device - Google Patents

Description

April 6,1965 H. c. EHLERT PERFORATOR INITIATING DEVICE 3 Sheets-Sheet 1 Filed Sept. 2B, 1962 INVENTOR.

/IT'ORNEV bf. C. Vf/erf April 6, 1965 H. c. EHLERT 3,176,770

PERFoRAToR INITIATING DEVICE Filed Sept. 28, 1962 3 Sheets-Sheet 2 ATTORNEY April s, 1965 Filed Sept. 28, 1962 H. C. EHLERT PERFORATOR INITIATING DEVICE 3 Sheets-Sheet 3 H. C". f77/erf IN VENTOR.

A fr0/wf y United States Patent O 3,176,770 lJERFURATOR HWITHATING DEVICE Harry Cern Ehlert, Houston, Tex., assigner to Camco, Incorporated, Houston, Tex., a corporation of Texas Filed Sept. 28, 1962, Ser. No. 226,898 l Claim. (Cl. 16d-55.1)

This invention relates to an improved wire line tool to be run through oil and gas well tubing and for perforating the tubing wall at a preselected depth.

At various times throughout the life of a producing well, there will be occasions to perforate or to install an orifice button at some given depth in the tubing wall to establish communication between opposite sides of the tubing wall. Common practice is to employ a perforator tool whose actuating power is supplied by an explosive charge and to lower the tool into the tubing to approximately the desired perforating location on a flexible line which can be manipulated for a jarring action to lire the charge. Misfiring from attempts to free a stuck tool, with sudden changes in line tension, and accidental jarring often open the tubing wall at an undesired location and neces sitate costly remedial measures and in any event there are many well equipment conditions which make for dificulties in accurately locating the conventional perforating tools at the point to be perforated.

An object of the present invention is to provide an improved means for precisely positioning perforations and within as little as one-half inch from the selected depth point and at regions spaced from tubing end connections.

A further object is to provide the tubing string with marker stations at known depths and which offer no interference to well tool passage but which can be preselected to effect automatic response of the tool equipment incident to traverse of the particular station.

Another object is to provide a tubing perfcrator tool which is insensitive to both upward and downward jarring and to banging laterally against the tubing wall so that perforation control is better assured even in crooked and partially obstructed tubing.

A still further object is to provide a tool comprised of separable subassemblies frangibly joined in end to end succession, one as a perforator unit and the other as a marker responsive running tool unit, so that if the more simple and less costly perforator unit should become stuck, its disconection at the frangible joint will enable the separated and more valuable running tool to be retrieved and then accommodate fishing operations to recover the stuck lower portion.

Other objects and advantages will become apparent from the following speci'lication taken in connection with the accompanying drawings, wherein:

FIG. l is a vertical section of a `portion of a well tubing in -which is being run the perforating equipment of which parts are shown in section and in elevation respectively;

` FIG. 2 is a view similar to FIG. l but with the parts shown immediately following completion of a perforating operation; i

FIG. 3 is a view like FIGS. l and 2 but shows the perforating tool being run upwardly in the tubing and also embodying certain modifications;

FIGS. 4A and 4B are companion vertical sectional views illustrating a fragmentary part of the tool shown in FIG. l immediately adjoining the releasably coupled ends of the two separable subassemblies and on a larger scale; and j FIGS. A5A and 5B are companion vertical sectional views of a fragment of the modified tool of FIG. 3 and on a larger scale.

In FIGS. l and 2 there is illustrated a wire line susl'ifl'id Patented Apr. 6, i965 lCC pended tool equipment consisting of a lower perforator subassembly unit P and an upper running tool subassembly unit R releasably coupled in end to end succession for travel through a well tubing string T to a selected depth at which the tubing wall is to be pierced into the surrounding annular space between the tubing and the well bore wall which usually is lined by tubular casing C.

The perforator unit is made up of a hollow tubular main body 1 housing a longitudinally slidable driver rod 2 terminating downwardly in an inclined wedge face co-operatively fitted to the back of a laterally projectable piston 3 which is movable outwardly through a mating opening in the wall of the tubing 1. Optionally, the piston 3 may be locked by a shearable element, not shown, in the retracted position illustrated in FIG. 1 and it has releasably fitted to its forward face a punch or orifice button 4. Above the sldable wedge pin 2 there is mounted within the top of the housing 1 a cartridge 5 containing an explosive charge of lpowder and a detonator cap. Firing of the charge, as by a downwardly directed hammer blow on the detonator cap, will release the stored energy of the charge in the form of a rapidly ,expanding gas and push the wedge pin 2 downwardly for projecting the piston 3 to drive the punch or orifice button l through the tubing wall. An instantaneous action occurs and thereafter further movement of the piston 3 breaks its mounting connection with the orifice button 4.

The expendable cartridge 5 has an external locating top liange 5a, as best seen in FIG. 4B, .and is held against an upwardly facing shoulder of an internally threaded counterbore upper end portion of the main body 1 by means of a fitting. la threaded downwardly within the counterbore end portion. This end tting la terminates upwardly in a reduced diameter projection having a necked and headed fishing formation 1b.

At the time of iinal assembly of the units P and R, a bottom terminal skirt portion 6 is sleeved over the fishing head end portion A)lb and the interiitted parts are releasably secured together by one or more frangible elements or shear pins 7.

Located within the hollow fitting 1a is` a short length firing pin 8 for transmitting downward force on the firing cap of the cartridge S and also slidably located within the iitting la and in end to end abutment with the firing pin 8 is the lower end of a motion transmitting pin or plunger 9. This plunger extends upwardly into and forms a part of the running tool R and terminates upwardly in a head 9a and has a slight lost motion slot and pin connection lil with a tubular sleeve portion 1l which forms a downward continuation of and has a screw threaded connection with the lower end of a plunger stem 11a. A shear pin 12 initially joins the plunger sleeve 1l with the tubular housing 6a which is a sectional part of the main body or housing of the running tool R.` This shear pin connectionlZ is effective to immobilize the plunger assembly including the parts 9, il and 11a against slide movement and the imposition of unintentional downward force on the tiring pin 8. The shear pin l2 will yield or be broken under stress imposed in opposite directions on the main body Vof the'tool and on the upper end of the plunger stem lla upon the tiring of an explosive charge contained within the cartridge 13 located within the housing immediately above the upper end of the plunger 11a. By reason of the lost motion connection lil, down travel of the lower plunger section 9 in unison with the upper plunger section 11a for firing the cartridge 5 is delayed until after the shear pin l2 has first been broken. j

The cartridge 13 contains an electrically actuated detonator or squib contained within an electric` circuit which includes batteries and control switches protectively enai closed within the upper portion of the main body of the running tool R together with control means which upon presentation within a magnetic iield will be actuated and effect ,the closing of thenormally open electric circuit containing the squib whereby to fire the cartridge 13 and thereby depress the slide plunger assembly after irst breaking the shear pin l2 and then delivering the necessary hammer blow through the lost motion connection 1d to the tiring pin 8 for effecting the perforating operation. The circuitry under control of the magnetic eld sensing means is more fully disclosed in Patent No.

Y 3,105,547. Accordingly, there is shown in FIGS. l and 2 in broken lines a pair of field sensing or magneto devices 14 and 15 enclosed within the housing of the running tool R in longitudinally spaced apart relation. The pole Ypieces of the magneto devices are aligned with field expositioned while the uppermost magneto device is mounted for longitudinal adjustment to present its poles selectively with any horizontal row of field extender plugs 16. Each magneto device when infiuenced by a magnetic ield, responds to close a pair of normally open switch contacts and both sets .of switch contacts are in series circuit relation so that the circuit involved will remain open except When both magneto devices are concurrently inluenced by magnetic fields.

The closing of an actuating circuit for a perforating operation can take place only at a selected location within the tubing andas related to a marker containing station forming a part of the tubing string. Thus, there is contemplated that the tubing string will be made up with a number of special nipples 17 each having a counterbored internal pocket to receive a stack of rings ld. As best seen in FIG. 5A, the stack of rings includes two rings of nonmagnetic material, in each of which are located a pair of longitudinally spaced apart rows of circularly spaced apart magnets 19. The magnets will be arranged so that the inner faces of magnets in one row will be of opposite polarity to the inner faces of the magnets in the other rowV for the protrusion of a fairly strong magnetic field interiorly of the tubing string. The remaining rings of the stack will be spacers and will enable the longitudinal spacing between the two magnet carrying rings to be varied in each of the nipple sections )17. Thus a pair of inwardly protruding magnetic fields provide a marker station at each of the several nipples incorporated in the tubing string and the fields will be separated longitudinally at distances diiering from one another at the several stations. Accordingly, when a perforation is to be made in the tubing string below any one nipple whose depth is known, the magneto devices ld and of the running tool will be adjusted to a spaced apart relation which corresponds to whatever the,V

:iield spacing isin the particular nipple. ln FIGS. l and 2 the magneto devices have their spacing selectively set to correspond to the spacing of the magnetic iields of the nipple shown. Accordingly,.when thetool is lowered into the tubing string and as each magneto device traverses any magnetic field, the-switch contacts controlled by that magneto device will close. inasmuch as the switches are connected in series, their circuit will remain open until pboth magneto devices concurrently traverse the magnetic fields to which the selected spacing is coded or in correspondence. immediately thathappens, the cartridge 13 Iwillbe fired and furnish the necessary jar to detonate the cartridge 5 and power the perforating tool for the wall piercing operation.

ln the-.modified embodiment of FIGS. 3, 5A and 5B,

" provision is made for providing a much longer over-all wire line tool for effecting a perforating operation at considerable distance below a marker station. The perforator subassembly, including the tubular housing t,

the slidable wedge 2 and the laterally projectable piston 3, is slightly modified at its upper end in that the fishing head portion 2l encloses a conductor 2.7. enclosed within an insulator sleeve 23 and provided at opposite ends with sockets for electrical connections. The lowermost connection is joined to an electrically responsive vsquib `for detonating the powder charge within the cartridge unit 2d. The ring of the cartridge 24 provides the force for driving the wedge 2 downwardly and the transference of that motion to the piston 3 in order to set the orifice button d in the wall of the tubing. y

Current is delivered to the cartridge 2d through a long conductor cable 25 having detachable connection at its lower end with the conductor 22 and connection at its upper end with a bulkhead conductor 25a and the long length cable is protectively enclosed within an elongate spacer tube 26 of a length unlimited except for practical consideration, such as the distance between succeeding marker stations in the tubing string. At its lower end, the spacer tube 26 carries a tubular skirt 27 lwhich is sleeved on the shing head 2l of the perforator unit and is releasably secured thereto by one or more frangible or shear pins 28. At its upper end, the spacer tube 26 is joined to the tubular housing 29 of the running tool and which also encloses the energy supplyingmeans, Vsuch as batteries and the circuit control devices. FIG. 5A

shows a pair of magnetic eld sensing devices protectiveiy Y selected tubing nipple, by insertion between them of interchangeable spacers Si? of proper length.

Each sensing device involves Va pair of longitudinally spaced apart pole pieces 3l., shown in FlG.'5A as being in alignment with two sets of nipple mounted magnets so as to be simultaneously within the respective magnetic fields for concurrently closing a pair of series connected switches and efecting instantaneous firing of the carridge 2/3. Between each pair of poleypieces is located'a permanent magnet 32 pivoted on a trans erse rocker axis intermediate the ends of the bar magnet. The rock axis is closer to one of the pole pieces 3l than to the other and hence magnetic attraction acts to bias or rock the magnet to a rest position, but should the pole pieces move into the influence of a magnetic field of opposite polarity,

Vthe magnet will rock away from its position of rest. One

modified forms as come Within the scope of the appended.

claim.

What is claimed is: ln combination, a tubing string having marker means roviding an inwardly protruding magnetic field, perforating equipment to be lowered in the tubing string and including housing means, a laterally projectable member mounted by the housing means and carrying a tubing wall punch, a force transmitting wedge engageable with the member, means for imposing force on said wedge including a first explosive charge positioned by the housing means to be tired for furnishing said force, another explosive charge in the housing means, a rstl plunger slidably itted within the housing means and exposed to direct action thereon of the explosive force of the secondV mentioned charge upon firing of the same, a frangible member initially anchoring said plunger to the housing means, a second plunger slidably fitted within the housing 5 means for transmitting force to re the first mentioned charge, a lost motion connection joining said plungers and compelling breakage of said frangible member in advance of unison slide travel of said pungers, electrically actuated means to `lire said second mentioned charge in- 5 cluding a normally open electric connection, a connection closing switch and a magneto device operative on the switch to close the same and positioned by the housing for operation under influence of said magnetic eld upon traverse thereof.

Kinley 166-55.1 Kinley 166-55.1 Jobe 166-55.3 Ownby et al. 166-55.1 Ownby 166,-65 Ownby 166-65 Raulins l6665 CHARTE; E. @"CONNELL, Primary Examiner.

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