Multiple wire scratcher for wells

April 14, 1953 κ. a. wright 2,634,813

MULTIPLE WIRE SCRATCHER FOR WELLS Filed Aug. 14, 1948

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Patented Apr. 14, 1953

2,634,813

UNITED STATES PATENT OFFICE

2,634,813 MULTIPLE WIRE SCRATCHER FOR WELLS Kenneth A.. Wright, Los Angeles, Calif.

Application August 14,1948, Serial No. 44,373 (CI. 166—18) away showing a multiple wire seratcher embodying my invention, and positioned, on a pipe- extending into, a well bore.

Figure 2. is a perspective, view showing one ⁵ of; the. multiple wire seratcher fingers on, an. enlarged scale.

Figure 3 is a perspective? view showing the underside of the retainer.

Figure 4 is a sectional view partly broken, away 10 taken substantially on the lines 4—4, as shown in. Figure. 2.,

Figure 5 is, a sectional detail taken substantially on the lines 5—5 as shown in Figure 2.

Figure 6 shows a modified form of my in15 vention in which the individual seratcher fingers, are mounted, on strips? carried on the external surface af a well pipe.

Figure 7 is a. sectional view illustrating a further modification in which the? reenforce20 ment at the. inner end of the shank is received, in telescopic relation with the forward end of the retainer to provide a. bearing surface.

Figure 8 is- a sectional detail taken substantially on the lines 8,-8 as shown in Figure 7.. 25 Referring to the drawings, the carrier element, or sleeve ID- is. adapted to encircle a well pipe such as the casing 11.. The sleeve may- be fixed to the casing IL by welding or by any other conventional, means, or may be loosely mounted30 on the casing and positioned between the stop lugs (not shown) carried on the external, surface of the casing ί I. The sleeve 10 may comprise a single integral ring or it may be. split, for installation on casing having enlarged _3g threaded connections at each end.

A plurality of multiple wire, seratcher fingers, generally designated 12 are fixed on the ring, 19 and extend upwardy- and outwardly, therefrom. Each of these fingers 12 includes a. re40 tainer 13 having a channel 14 along its underside to receive a plurality of individual spring wires 15. Tbe wires 15 are each, doubled, at their inner end 1’6. after the manner of a hairpin, and these wires project outwardly and up45 wardly in a group or bundle to form: the shank, IT and tip 18. A tubular reenforcing collar 19. is positioned on the wire bundle between, the, tip 18. and shank IT and is bent after assembly on the wire bundle so that a permanent set. 50 is effected, whereby, the tip 13 extends at an angle to the shank as shown. A similar tubular reenforcing collar. 20- is bent after assembly onthe? wire bundle, so that a permanent set? is· developed and so that the shank IT extends at55 an angle to the attachment section 21. This angle is clearly shown in Figure 4,

Claims.

This invention relates to the; well drilling; art and: is particularly directed, to. a. cleaner¹ or seratcher.· adapted, tn be carried: on a pipe- insertable· into; a well. bore_;.

This; application constitutes a. continuation.in-part: of: my co-pending applications,. “Finger, for Well Cleaners: or Scratchers,” Serial No:. 709,489;: “Mud. Cleaners Applicable: to Well Casing: or the. Like;” Serial No. 709,490; and “Well Gleaning; and Centering Tool,” Serial No. 709,491; all filed, November. 13; 1946,. and all now? abandoned;.

The principal object of the present invention, is: tn; provide an. improved, form, of seratcher for wells employing: multiple: wire fingers and adapted to: minimize disturbance of the mud. cake while going: into, the well, but to provide eff ective means, for removing the mud cake when raised, upwardly within, the well bore. An important: use: of this, device is in connection with well cementing: operations, in which, it serves to remove the mud; cake: and prevent its reform:ing,. so that the cement; may directly contact the wall of the hole and prevent channeling in the- cement sheath;

Another, object is to provide a seratcher device of this type having flexible fingers formed of wire bundles.

Another object is ta provide such a. device in which: the flexibility of the fingers minimizes damage to: the: device, which would, otherwise be caused by the usual rough handling of scratcher-equipped well pipe, prior to insertion into. a. well. bore'..

A. related, object is?, to: provide a sleeve adapted to: be: carried: on the: external; surface, of a? well pipe: such: as a: casing,., and having: a. plurality of multliplewirescratcherfingersfixedon the: outer periphery of the sleeve and; extending upwardly and;, outwardly from the sleeve; for contact with the- walk of: a well:, bore.

Another object is, to provide? reenforcement means for: such; multiple: wire, seratcher fingers positioned at: the? inner, end. of the multiple wire shank adjacent, the retainer or body which secures the finger to the sleeve.

A. further object is to. provide a reenforcement at the: inner end: of: the? multiple: wire, shank: and which projects¹ within· a. recess: provided, at the, forward end of the retainer, whereby the retainer and reenforcement cooperate to provide a bearing, surface, adjacent the·, inner.· end: of the shank.

Other objects and advantages will· appear hereinafter.

In the? drawings:

Figure 1 is an elevation view partly broken

2,634,813

The loop 16 on each pair of spring wires included in the bundle is positioned within an enlarged recess 22 provided within the retainer 13 at one end of the channel 14. A tongue 23 formed integrally with the body of the retainer i3 extends upwardly into the recess 22 and through the loop 16 of each of the spring wires. The channel 14 is proportioned so that the spring wires substantially fill the channel and rest against the external surface 24 of the sleeve IG. Enlarged looped ends 16 of the wires are wider than the width of the channel. 14, and accordingly cannot be pulled out of the channel in an axial direction. The tongue 23 acts further to anchor the wires and prevents the doubled end of each -wire from turning relative to the retainer 13.

Opposite ends of the retainer 13 are provided with pairs of tabs 25 and 26 which provide means for securing the retainer to the sleeve i 0. Any suitable form of attachment may be used, but I prefer to spot weld the tabs 25 and 26 to the sleeve 10 as indicated at 27. Since the retainers are mounted in an inclined position on a cylindrical sleeve they are shaped after the manner of a helix and the tabs 25 and 26 are not positioned in the same plane.

The retainers 13 are mounted in inclined nested relation on the sleeve 10. Since it is desirable to employ a relatively large number of scratcher fingers on the sleeve and thus insure maximum cleaning ability of the tips 18 against the wall 28 of the well bore, the retainers 13 are mounted as close as possible to each other on the sleeve 10. One of the upper tabs 26 on each retainer projects between the upper and lower tabs on the next adjacent retainer as shown in Figure 1, and by this nesting arrangement a larger number of retainers may be secured on the periphery of the sleeve than could be accommodated if the parts were not nested. The angle of mounting of the retainers on the sleeve 10 and the angle of bend at the collars 19 and 20 is so chosen that when the fingers are deflected inwardly into contact with the well bore 28 from their normal free condition as indicated by the dotted lines 29 in Figure 1, the tip 18 of each of the fingers extends substantially vertically upwardly. In this way minimum resistance is offered to the mud cake which builds up within the bore hole during drilling operations when the sleeve 10 is moved downwardly in the bore hole.

When the sleeve 10 is moved upwardly within the bore hole the fingers 12 flex outwardly and the tips 18 engage the mud cake and remove it from the wall of the well bore. The flexing of the finger 12 occurs primarily along the shank 17 and the extending portion of the attachment section 21 and rotary movement of the bundle occurs within the forward portion of the channel i4 at the opposite end from the tongue 23. The reenforcing collar 20 performs the highly desirable function of maintaining the wires in assembled relation as a group adjacent the point of greatest stress on the wires. This serves to prevent separation of the individual wires adjacent the extending portion of the attachment section 21 and thus contributes toward reliable operation of the finger 12 under repeated flexing.

A single wire having a cross-section equal to the combined cross-sections of the bundle of wires illustrated and possessing the same physical properties would be incapable of flexing to the extent provided by the multiple wire bundle. This is true because the wires making up the shank 17 flex individually and hence the entire bundle may be deformed to the extent permitted by each of the relatively small wires, rather than to the lesser extent which would be permitted by a single wire having a cross-section equivalent to the total of the individual smaller wires. The provision of the reenforcing collar 20 insures that the individual wires shall not spread adjacent the attachment section 21, but on the contrary shall flex from a common location and thus provide flexing movement which is as uniform as would be provided by a single heavy wire.

In the modified form shown in Figure 6 the individual fingers 12 may be of the same form described above, but each of the retainers 13 is mounted on a vertically extending carrier element or strip 50 secured to the external surface of a well pipe 51. The retainers 13 are preferably mounted in nested relation in order to provide as many fingers as possible on the strip 50. Other strips 52 may be mounted on the pipe 51 and located at a different point on the circumference. These strips 50 and 52 are preferably positioned'· in overlapping relationship so that when the well pipe 51 is rotated no gap is left between the groups of fingers. The well pipe 51 may be raised' and lowered in the hole during the cementing operations and simultaneously rotated if desired.: In this way the mud cake is removed and prevented from reforming while the cement is sealing the annular space between the well pipe 51 and the bore hole 28.

In the modified form of my invention shown in Figures 7 and 8 the forward end 60 of the retainer 13α is extended and is adapted to receive a tubular projection 61 on the collar 20α in overlapping relationship. The bearing surface 62 is thereby provided between the retainer (3α and: the reenforcing collar 20α. This inter-engage-.: ment and bearing surface contribute to the stability of the lower end of the shank 17 under flexing action and further insures reliable action of the finger under repeated flexing operations. The tubular projection 61 is maintained in contact with the forward end 60, since the projection 61 lies against the outer surface 24 of the sleeve 10.