US2662474A - Well casing perforator - Google Patents

Description

Dec. l5, 1953 G. F. TURECHEK ETAL 2,662,474

WELL CASING PERFORATOR Filed July 25. 194.9

Y Lmle @TTOIQNEV Patented Dec. 15, 1953 2,662,474 WELL CASING PERFORATOR George F. Turechek, Los Angeles, and Will H.

Lindsay, Jr.,

Lawndale, Calif., assgnors to Lane-Wells Company, Los Angeles, Calif., a.

corporation of Application July 25, 1949, Serial No.

Delaware Claims. (Cl. 102-20) This invention relates to perforators adapted to be lowered into boreholes, particularly oil and gas well boreholes, for the purpose of piercing or perforating the casing therein or surrounding formations or both, at one or more points. More particularly it pertains to perforators of the aforesaid type, adapted and intended to use detonating explosives of high velocity and of the general character and form known as shaped charges, as, for example, the type disclosed in U. S. Patent No. 2,399,211 to C. O. Davis et al., issued April 30, 1946.

Early perforators employing either one shaped charge, as in the beforementioned patent, or a number of such shaped charges, were expendable structures, being entirely destroyed when fired, with only the ring line or supporting conductor cable being recovered from the borehole. Such perforators, adapted to hold the shaped charges, were constructed of various materials such as sheet metal, cement or suitable plastics. Expendable perforator devices such as these had a number of disadvantages, among them being high cost, the leaving of debris in the borehole, the subjecting of the surrounding casing to high stresses, and also the inability to selectively lire less than all of the shaped charge units contained in them simultaneously, lest the unred charges be destroyed by those fired.

It soon was evident that the beforementioned disadvantages could be obviated and other advantages realized by employing retrievable perforator devices for containing the shaped charges and which would be reloaded repeatedly and could be constructed in separate units capable of being separately red.

In subsequent attempts to develop a retrievable `perforator device, the body thereof was formed of a relatively thick walled steel tube having a plurality of longitudinally spaced, laterally directed ports,

However, it was found that, after one or several rings, the perforator body, which Was subject to the general explosive force extending in all directions from the shaped charge unit, became elongated or otherwise distorted to such an extent that upon reloading with a new shaped charge liner assembly, at least some of the charges failed to register accurately with the body ports and were, in frequent instances, misaligned therewith suiciently to cause the blast or jet reduced, to some extent, its desirable penetrating qualities.

It is therefore an object of the invention to pro" in the perforator device.

Still another object is to position and to maintain the shaped charge units accurately located and positively held in alignment relative to the ports in the perforator body even after the body may have undergone distortion from the detona-v tion of prior charges.

Still another object is to provide an improved method and apparatus for loading and mounting shaped charge units individually in a perforator body.

The objects of the present invention are accomplished in general, type perforator having a heavy walled, cylindrical body containing a plurality of radially di-V rected ports therein and in which the shaped charge or charges are each individually and i ndependently mounted in accurately aligned position with respect to the center of each port and by means cooperating with each port in the perforator, independent of the overall dimensions of the perforator body, thereby minimizing if not entirely avoiding the ill effects from distortion created by prior and repeated use of the perforator.

`Other objects, advantages and features of nov-v elty of the invention will be evident hereinafter.

In order to illustrate one preferred embodiment` of the invention and the manner of its use, at-

by providing a shaped charge:

tention is now directed to the accompanying drawings, in which:

Figure 1 is a view, partly in elevation and partly in longitudinal section, of a completely assembled perforator ready to be lowered into a well borehole.

Figure 2 `is a transverse sectional view, on an enlarged scale, taken on line 2-2 of Figure l but showing a typical shaped charge unit therein partly in plan view and partly in section; and

Figure 3 isv an exploded view in perspective of the parts for 'securing a shaped charge unit in place in the perforator body.

The perforator apparatus comprises a perforator body I0, as shown in Figures 'l and 2., in the form of a thick walled, elongated tube or cylinder, closed at its lower end by a tapered bull plug 1II, The thick wall of the body II! has a series oi longitudinally spaced, radially directed openings or ports I2 extending therethrough to the inside of the central bore or chamber I3, each por-t being enlarged on the outside by a short counterbcre l5. Such series oi ports i2 enl-y two oi `are shown ,in Figure l :for the reason that `for convenience of illustration the View of the gun body .I .is :shortened by cutting away, for the ,most 'part duplicate portions thereof) rmay be arranged along the body Il) in any desired pattern. One suitable arrangement which is frequently used 1s to place the ports :I2 in a spiral pattern along body Ml.

At each port I2 a shaped charge unit such as shown at i6 is Vadapted to be mounted so that the `iet `shaped blast projected .from the forward end thereof will issue through the To assist in positioning and accurately maintaining each such charge .I6 in centered relation to its respective port I2, the inner wall of gun body I0, dametrally opposite each port, is provided with suitable charge unit, Preferably such means takes the form of a radially directed cylindrical recess l1, and the adjacent rear end I8 of the vcharge is cooperatively shaped to lit within the recess I1.

To support the other end lof the shaped charge unit l5, securing means are inserted through port I2 to .retain .charge IB in place and to maintain end I8 seated in recess I1, such securing means also serving to support and to center the .adjacent forward end of charge I6 in axial alignment ,relative to the center of its port I2. Such securing means comprises an annular charge aligner diaphragm or ring member 20, of suitably rigidmaterial, such as for example, thin sheet aluminum, brass or steel. The aligner diaphragm is adapted to iit snugly within a short counterbore 22 formed in the forward or larger :end of the shaped charge unit and to be pressed in engagement with .an internal abutment shoulder 23 formed at :the bottom or inner end of the said counterbore as best shown .in Figure 2. The aligner diaphragm 20 is formed with an integral approximately conical outer marginal portion 25 and an inwardly turned, inner marginal portion 26 terminating in a narrow transversely or radially extending iianged portion 21, thereby providing an inner annular recess terminated by the annular seat formed by said flanged portion 21. The aligner ring member 2li is pressed into counterbore 22 of charge unit I6 before the latter is inserted into the axial bore I3 of gun body Iii and when the shaped charge unit I is properly positioned opposite its port I2, and the rear end portion thereof seated in recess I1, seat 21 of aligner ring 2li will be directly in axial alignment center 'of the port.

means to engage the rear end or the with .the center o 77,5 mounted and its container port I2. An annular expansible member or sleeve 30 is adapted to be inserted through port I2 into recess 25 and seated against shoulder 21 to secure charge unit I5 in place. Member 3i) preerably takes the form of a sleeve as best shown at 30 in Figure 3 of any suitable material such as nbre or plastic and of an external diameter to nt, with slight clearance, the inside diameter of the port I2. Sleeve 30 is slotted longitudinally at a plurality of circumerentially spaced points as shown at .3l and the tongues 32 so formed may, in some cases, have an outward or radial set or bias in Aorder to securely grip the wall about :port I2.V However, in order to make'the sleeve member 3B adaptable for securing charge units IS lin piace after-the gun body has been used a number of times and the blasts of the charges may have expanded and slightly distorted port I2, the wall of the split member or sleeve 30 is preferably tapered in thickness by an increasing internal .diameter toward its vslotted fend yas indicated in Figure 2, .and a mating inner sleeve 33 is termed with the lwall similarly tapered bye. decreasing outside diameter 'toward the inner end, and this sleeve 35 is adapted tc be thrust into sleeve `30 and thus utilized positively to Aexpzmrl the slotted portion mi .sleeve 30 into gripping en' gagement lwith the inside surface of the 'port IIR. The tapers lon these two sleeves 30 and 33 are the same and zare :such as to be frictionally self flocking upon yone another so .that when sleeve 33 .is forcibly pressed or hammered into split sleeve 30 the tongues of the latter are expanded radially and locked inpositicn in frictionalengagement with inside surface of the wall of port I2 and the sleeves 36 and 33 not separate axially 'with respect to one another .under the vvver'laging force thus applied. 'The ,splits or slots 31 in sleeve 3B permit 'wide expansion ci .the tnusformed ltongues 32 of this sleeve so that it will `fnnctinn ,equally well after ports i2 have become considerably ex panded through extended use. vThe thin metal of which the aligner ring 2D is preferably con-- structed gives this ring a certain axial flexibility so 'that it may 'maintain a spring-like axial `ferne on .charge -unit IS urging'it rearwardly suinciently to keep the small end I8 vthereof irmly seatedin recess I1. The close lit .of aligner ring 20 in counterbore 22 of charge unit IB and of sleeve 3l in recess .2B maintains cha'rge vunit I5 at all times in rigid axial Valign-ment with port I2.

For convenience, reference c racter heretofore been utilized to indicate the charge unit as a whole including the explosive contents but it actually indicates the casing for the charge of explosive A, which may be of the dctonating typedescribecl in the abovementioned Davis .et al, Patent No. 2,393,211., shaped or Vmolded with conical depression therein racing toward port i2 as shown in partial section in Figure 2. The casing t6 for the shaped explosive charge may be of any suitable material such as Bakelite, Lucita etc, The small or rearward end I3 of the charge unit Il; has an opening or passage 35 extending transversely therethrough to receive a detonating fuse or cord vas shown at 36. `As shown, theforward end of charge unit 1.6 is IAofgreater diameter than that of port I2 and has its forward face rounded as viewed in Figure 2 t0 conform generally to v,the inside `surface of bore I3 of body l0.

In loading the perforator body, charge units .I6 are insertedcne at a time, and each is individually in accurately pos-tioned relation to its a suitable concavity or respectiveY port as hereinafter described. The method is as follows:

Fuse cord 36 is rst passed through the fuse passage 35 of the first charge unit and an aligner 2Q is pressed into the counterbore 22 in the forward end of the charge unit casing; the charge unit is then preferably inserted through the upper open end of the perforator body and lowered or moved longitudinal- 1y therein to the level of the lowest or bottom port in the body. Tongs to grip the charge unit may be utilized for this purpose and a. suitable form of such tongs are shown and described in the copending application of Will H. Lindsay, Jr. and Robert A. Phillips, Serial No. 106,567, filed July 25, 1949.

The charge is manipulated by the tongs and through port I2 to align rear end I8 thereof with the lowest inner body recess I1 and to push the end of the charge into the said recess. Split sleeve 30 is then inserted through port I2 and forced into seating engagement against flanged seat 21 on the aligner diaphragm 20, thereby centering charge unit I 5 relative to the port I2 and putting diaphragm under slight axial compression to maintain rear end I8 of the charge unit, forced into' recess I I in the inner opposite wall of gun body I 0. If needed, inner tapered sleeve 33 is then forced into the split end of sleeve to expand the latter and positively lock it in place in the port opening, sleeve 33 being always used when port I2 has been enlarged or distorted from the ring of previous charges. With the lowest charge securely in place a sealing disc or cap 31, of copper, brass or other suitable material, is forced into counterbore I5 of the port I2 to prevent ingress of any uid which may surround gun body I!) when the apparatus is lowered into and submerged in fluid in a borehole. The above steps are repeated with each succeeding charge unit, fuse 36 being threaded through the bores and aligning diaphragm 20 being mounted in each charge I6 in succession before the charge is inserted into the axial bore I3 of the perforator body I0.

When the perforator body I0 has been completely loaded and all ports sealed by seal discs as shown at 31, a cap supporting washer 34 carrying a blasting cap union 38 which is crimped to the end of the ignition cord 3B, is placed in the open end of body I0 and is secured in place, as shown, by threaded bushing sleeve 40 which makes threaded engagement at 4I with the inner, upper end portion of the wall of the perforator body I0. A detonating cap 42 to which a exible insulated conductor 43 is secured, is fastened to the upper end of the blasting cap union 38 before casing 44 and cable head 45 are secured in place. Fluidtight packings are provided at 46 and 41 to seal the upper end of body I0 against entrance of fluid. A conductor cable 49 of conventional design attached to the top of the cable head serves as a means to lower the perforator into the well and to conduct the firing current to the firing mechanism. The electrical connections between conductor 43 and the conductors in the conductor cable 43 are of conventional design and are contained in the cable head assembly 45, the lower end of which fits within the bushing sleeve 40 and makes threaded engagement with the latter as shown at 50.

From the foregoing it will be apparent that the present invention provides an improved form of perforator apparatus adapted to repeated use with high explosive shaped charge units, that the individually mounted charges are always accurately positioned and centered relative to the discharge ports regardless of distortion of the perforator body, and that the invention provides a novel method and apparatus for loading a shaped charge perforator.

While the invention has been herein described in what are now believed to be the preferred forms of its method and apparatus aspects, it is to be understood that the invention is not limited to the specific details of such forms but covers all modifications, changes and adaptations within the scope of the appended claims.

What is claimed is:

l. In apparatus for perforating well casings the combination comprising: a body having an axial bore therein; a series of radial ports extending from said bore through the wall of said body and disposed at intervals longitudinally of said body; a series of shaped charges within said bore, each charge being directed toward one of said ports; interengaging means on each charge and on the wall of said body diametrall'y opposite each port in said body; and aligning means extending from each said port to each said charge for securing the charge in place accurately centered as to its port, said aligning means comprising a ring engaging the forward end of each charge, an expansible sleeve inserted through the port and against said ring, and an inner tapered sleeve forced into said expansible sleeve to expand the same into frictional engagement against the inner walls of the port.

the wall of said body and disposed at intervals longitudinally of said body; charges within said bore, each charge being difor directing the blast from the charge through the center of the port, said aligning means c omprising an annular member fitting the forward end of each charge and formed with a concentric inner recess, a split sleeve extending from within the port and into seating engagement in said recess in said ring, and a tapered inner sleeve forced into said split sleeve to expand the said split sleeve against the walls of the port.

3. Apparatus for securing a shaped charge within a perforator body having an axial bore and a radial port extending from said bore through the wall of said body, said charge being insertable through said bore to a position to fire through said port, said apparatus comprising: an aligning ring to be fixed coaxially to said charge before insertion into said bore, said ring providing a coaxial, cylindrically shaped recess therein; an outer split sleeve making a slidable rit within said port and positioned in endwise seating engagement within said recess, said split outwardly increasing inside diameter; an inner sleeve having an inwardly decreasing outside diameter matching the inside of said outer split sleeve and adapted to be forced into said outer split sleeve to expand said outer sleeve into frietional engagement with the walls said bore through' the wall of said body, said of said port. apparatus comprising an aligning ring. to be xed 4. Apparatus for securing a shaped charge tothe circular forward end of saidY shaped charge within av pe'rorator body having an axial bore unit at theI concave end' thereof between such and a radial port extending from said bore concave end of the charge unit and the innerfwall through the wall of said body, the borewall havof said bore, said aligning ring having a central ing a recess formed in the inner surface thereof opening coaxial with said charge unit and `an diametrlically opposite said port, said charge being outwardly facing circular shaped recess conceninsertable through said bore to a position to nre tric with said central opening, a ltubular sleeve through said port, said apparatus comprising: io having an inner end arranged to be received in Cil:

an aligning ring tov be fixed coaxially to the forsaid recess with the` body of the sleeve spanning Ward end portion of said charge and providing the distance between said ring and the inner wall a coaxial, cylindrically shaped recess therein; of said bore and with the outer end of saidsleeve an expans'ible sleeve member adapted to make a being expansible and extending into` Ysaid port, slidable nt within said port and positioned in i5 and tubular means insertable intothe outer end end-wise seating engagement with said last of said sleeve for expanding said sleeve into bindirecess ;and an inner cylindrical member having a ing engagement with the wall of said port. tapered outside diameter, positioned in said outer GEORGE F. TURECHEK. split sleeve to* expand said outer expansible sleeve WILL H. LINDSAY,A J R; into frictional engagement with the walls of said '2o' port whereby Said charge may be port Refe'els the fue Of patent! alignment position with the rear end thereof UNITED STATES PATENTS seated in said rst recess. T f

5. Apparatus for supporting the forward end 2133528535 Tdqn'g; J B21361935. 'of a concave shaped charge unit, circular in cross- 25 2 402153 an' section within a perforated body which body has EH10 June 18' 1946 2,494,256 Muskat Jan. 10, 1950' an axial bore and a radial port extending from

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